Version 2.3.0

To fix a crash "Layout.swift: Fatal error: Attempted to read an unowned reference but the object was already deallocated"  which is reported at issue #440.

.github/FUNDING.yml

@@ -0,0 +1 @@
+github: SCENEE

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,40 @@
+> Please fill out this template appropriately when filing a bug report.
+>
+> Please remove this line and everything above it before submitting.
+
+### Description
+
+### Expected behavior
+
+### Actual behavior
+
+### Steps to reproduce
+
+**Code example that reproduces the issue**
+
+
+**How do you display panel(s)?**
+
+* Add as child view controllers
+* Present modally
+
+**How many panels do you displays?**
+
+* 1 
+* 2+
+
+### Environment
+
+**Library version**
+
+**Installation method**
+
+* CocoaPods
+* Carthage
+* Swift Package Manager
+ 
+**iOS version(s)**
+
+
+**Xcode version**
+

.github/workflows/ci.yml

@@ -0,0 +1,81 @@
+name: ci
+
+on: 
+  push:
+    branches: 
+      - master
+  pull_request:
+    branches: 
+      - '*'
+
+jobs:
+  build:
+    runs-on: macOS-10.15
+    steps:
+    - uses: actions/checkout@v1
+    - name: "Swift 5.1"
+      run: xcodebuild -scheme FloatingPanel SWIFT_VERSION=5.1 clean build
+      env:
+        DEVELOPER_DIR: /Applications/Xcode_11.3.1.app/Contents/Developer
+    - name: "Swift 5.2"
+      run: xcodebuild -scheme FloatingPanel SWIFT_VERSION=5.2 clean build
+      env:
+        DEVELOPER_DIR: /Applications/Xcode_11.7.app/Contents/Developer
+    - name: "Swift 5.3"
+      run: xcodebuild -scheme FloatingPanel SWIFT_VERSION=5.3 clean build
+      env:
+        DEVELOPER_DIR: /Applications/Xcode_12.3.app/Contents/Developer
+
+  testing:
+    runs-on: macOS-10.15
+    steps:
+    - uses: actions/checkout@v1
+    - name: "Testing in iOS 13.7"
+      run: xcodebuild clean test -scheme FloatingPanel -workspace FloatingPanel.xcworkspace -destination 'platform=iOS Simulator,OS=13.7,name=iPhone 11 Pro'
+      env:
+        DEVELOPER_DIR: /Applications/Xcode_11.7.app/Contents/Developer
+    - name: "Testing in iOS 14.3"
+      run: xcodebuild clean test -scheme FloatingPanel -workspace FloatingPanel.xcworkspace -destination 'platform=iOS Simulator,OS=14.3,name=iPhone 12 Pro'
+      env:
+        DEVELOPER_DIR: /Applications/Xcode_12.3.app/Contents/Developer
+
+  example:
+    runs-on: macOS-10.15
+    env:
+      DEVELOPER_DIR: /Applications/Xcode_12.3.app/Contents/Developer
+    steps:
+    - uses: actions/checkout@v1
+    - name: "Build Maps"
+      run: xcodebuild -workspace FloatingPanel.xcworkspace -scheme Maps -sdk iphonesimulator clean build
+    - name: "Build Stocks"
+      run: xcodebuild -workspace FloatingPanel.xcworkspace -scheme Stocks -sdk iphonesimulator clean build
+    - name: "Build Samples"
+      run: xcodebuild -workspace FloatingPanel.xcworkspace -scheme Samples -sdk iphonesimulator clean build
+
+  swiftpm:
+    runs-on: macOS-10.15
+    env:
+      DEVELOPER_DIR: /Applications/Xcode_12.3.app/Contents/Developer
+    steps:
+    - uses: actions/checkout@v1
+    - name: "Swift Package build"
+      run: swift build -Xswiftc "-sdk" -Xswiftc "`xcrun --sdk iphonesimulator --show-sdk-path`" -Xswiftc "-target" -Xswiftc "x86_64-apple-ios14.3-simulator"
+
+  carthage:
+    runs-on: macOS-10.15
+    env:
+      # Carthage doesn't fix issues on Xcode 12: https://github.com/Carthage/Carthage/releases/tag/0.36.0
+      DEVELOPER_DIR: /Applications/Xcode_11.7.app/Contents/Developer
+    steps:
+    - uses: actions/checkout@v1
+    - name: "Carthage build"
+      run: carthage build --no-skip-current
+
+  cocoapods:
+    runs-on: macOS-10.15
+    steps:
+    - uses: actions/checkout@v1
+    - name: "CocoaPods: pod lib lint"
+      run: pod lib lint --allow-warnings
+    - name: "CocoaPods: pod spec lint"
+      run: pod spec lint --allow-warnings

.gitignore

@@ -17,11 +17,13 @@ DerivedData/
 *.perspectivev3
 !default.perspectivev3
 xcuserdata/
+IDEWorkspaceChecks.plis
 
 ## Other
 *.moved-aside
 *.xccheckout
 *.xcscmblueprint
+*.xcsettings
 
 ## Obj-C/Swift specific
 *.hmap
@@ -29,6 +31,9 @@ xcuserdata/
 *.dSYM.zip
 *.dSYM
 
+## Swift Package Manager Specific
+.swiftpm/
+
 ## Playgrounds
 timeline.xctimeline
 playground.xcworkspace

.swiftformat

@@ -0,0 +1,3 @@
+--header "// Copyright 2018-Present Shin Yamamoto. All rights reserved. MIT license."
+--disable andOperator,anyObjectProtocol,blankLinesAroundMark,blankLinesAtEndOfScope,blankLinesAtStartOfScope,blankLinesBetweenScopes,braces,consecutiveBlankLines,consecutiveSpaces,duplicateImports,elseOnSameLine,emptyBraces,hoistPatternLet,indent,isEmpty,leadingDelimiters,linebreakAtEndOfFile,linebreaks,numberFormatting,redundantBackticks,redundantBreak,redundantExtensionACL,redundantFileprivate,redundantGet,redundantInit,redundantLet,redundantLetError,redundantNilInit,redundantObjc,redundantParens,redundantPattern,redundantRawValues,redundantReturn,redundantSelf,redundantVoidReturnType,semicolons,sortedImports,spaceAroundBraces,spaceAroundBrackets,spaceAroundComments,spaceAroundGenerics,spaceAroundOperators,spaceAroundParens,spaceInsideBraces,spaceInsideBrackets,spaceInsideComments,spaceInsideGenerics,spaceInsideParens,specifiers,strongOutlets,strongifiedSelf,todos,trailingClosures,trailingCommas,trailingSpace,typeSugar,unusedArguments,void,wrapArguments,yodaConditions
+

.travis.yml

@@ -1,45 +1,20 @@
-language: swift
+language: objective-c
 branches:
   only:
     - master
-    - next
-cache:
-  directories:
-  - build
-  - vendor
-  - /usr/local/Homebrew
-  - $HOME/Library/Caches/Homebrew
 env:
   global:
   - LANG=en_US.UTF-8
   - LC_ALL=en_US.UTF-8
-skip_cleanup: true
 jobs:
   include:
-  - stage: carthage
-    osx_image: xcode10
-    before_install:
-    - brew update
-    - brew outdated carthage || brew upgrade carthage
-    script:
-    - carthage build --no-skip-current
-
-  - stage: podspec
-    osx_image: xcode10
-    script:
-    - pod spec lint
-
-  - stage: check Maps example
-    osx_image: xcode10
-    script:
-    - xcodebuild -scheme Maps -sdk iphonesimulator clean build
-
-  - stage: check Stocks example
-    osx_image: xcode10
-    script:
-    - xcodebuild -scheme Stocks -sdk iphonesimulator clean build
-
-  - stage: check Samples example
-    osx_image: xcode10
-    script:
-    - xcodebuild -scheme Samples -sdk iphonesimulator clean build
+  - stage: "Tests"
+    script: xcodebuild clean test -scheme FloatingPanel -workspace FloatingPanel.xcworkspace -destination 'platform=iOS Simulator,OS=10.3.1,name=iPhone SE (1st generation)'
+    osx_image: xcode11.6
+    name: "iPhone SE (iOS 10.3)"
+  - script: xcodebuild clean test -scheme FloatingPanel -workspace FloatingPanel.xcworkspace -destination 'platform=iOS Simulator,OS=11.4,name=iPhone 7'
+    osx_image: xcode11.6
+    name: "iPhone 7 (iOS 11.4)"
+  - script: xcodebuild clean test -scheme FloatingPanel -workspace FloatingPanel.xcworkspace -destination 'platform=iOS Simulator,OS=12.4,name=iPhone X'
+    osx_image: xcode11.6
+    name: "iPhone X (iOS 12.4)"

Documentation/FloatingPanel 2.0 Migration Guide.md

@@ -0,0 +1,294 @@
+# FloatingPanel 2.0 Migration Guide
+
+FloatingPanel 2.0 is the latest major release of FloatingPanel. As a major release, following Semantic Versioning conventions, 2.0 introduces API-breaking changes.
+
+This guide is provided in order to ease the transition of existing applications using FloatingPanel 1.x to the latest APIs, as well as explain the design and structure of new and updated functionality.
+
+## Updated Minimum Requirements
+
+* Swift 5.0
+* iOS 11 (iOS 10 is still the deployment target, but not tested well)
+* Xcode 11.0
+
+## Benefits of Upgrading
+
+* __Top, left and right positioned panel__
+  * FloatingPanel is not just a library for a bottom positioned panel, but also top, left and right positioned ones.
+* __Objective-C compatibility__
+  * The entire APIs are exposed in Objective-C. So you can use them in Objective-C directly.
+* __Flexible and explicit layout customization__
+  * `FloatingPanelLayout` is redesigned. There is no implicit rules to lay out a panel anymore.
+* __New spring animation without UIViewPropertyAnimator__
+  * The new spring animation uses [Numeric springing](http://allenchou.net/2015/04/game-math-precise-control-over-numeric-springing/) which is a very powerful tool for procedural animation. Therefore a library consumer is easy to modify a panel behavior by 2 paramters of the deceleration rate and response time.
+* __Handle the panel position anytime__
+  * `floatingPanelDidMove(_:)` delegate method is also called while a panel is moving. The method behavior becomes same as `scrollViewDidScroll(_:)` in `UIScrollViewDelegate`. And in the method a library consumer is able to change a panel location.
+* __Update the removal interaction's invocation__
+  * Now you can invoke the removal interaction at any time where you want. There is no restrictions in the library.
+* __Fix many issues depending on API design__
+  * See the following sections for details.
+
+## API Name Changes
+
+* `FloatingPanelPosition` is now `FloatingPanelState`.
+  * `FloatingPanelPosition` in v2 is used to specify a panel position(top, left, bottom and right) in a screen.
+* `FloatingPanelSurfaceView` is `SurfaceView` only in Swift.
+* `FloatingPanelBackdropView` is `BackdropView` only in Swift.
+* `FloatingPanelGrabberHandleView` is `GrabberView` only in Swift.
+* "decelerate" term is replaced with "attract" because the panel's behavior is not unidirectional, but going back and forth so that it is settled to a location.
+
+## `FloatingPanelController`
+
+* `layout` and `behavior` properties can be changed directly without using the delegate methods.
+
+```swift
+fpc.behavior = SearchPaneliPadBehavior()
+fpc.layout = SearchPaneliPadLayout()
+fpc.invalidateLayout() // If needed
+```
+
+* The second argument of `addPanel(toParent:)` changes to specify an index of subviews of a view in which a panel is added.
+
+```diff
+- public func addPanel(toParent parent: UIViewController, belowView: UIView? = nil, animated: Bool = false) {
++ public func addPanel(toParent parent: UIViewController, at viewIndex: Int = -1, animated: Bool = false) {
+```
+
+* `surfaceOriginY` is now `surfaceLocation`.
+* `updateLayout` is now `invalidateLayout`.
+* The scroll tracking API is changed a bit to support multiple scroll view tracking in the future.
+  * Now `untrack(scrollView:)` is used to disable the scroll tracking.
+
+## `FloatingPanelControllerDelegate`
+
+* `floatingPanelDidEndDragging(_ vc:willAttract:)` is added to check whether a panel will continue to move after dragging.
+* `floatingPanelDidMove(_:)` behavior changes. The method is also called in the spring animation.
+* The removal interaction delegate is updated.
+  * `floatingPanel(_:shouldRemoveAt:with:)` is added to determine whether it invokes the removal interaction in any state.
+  * `floatingPanelWillRemove(_:)` is added.
+* `floatingPanel(_: FloatingPanelController, layoutFor size: CGSize)` is added to respond to a layout change in regular size classes on iPad.
+
+```swift
+func floatingPanel(_ fpc: FloatingPanelController, layoutFor size: CGSize) -> FloatingPanelLayout {
+    if aCondition(for: size) {
+        return SearchPanelLayout()
+    }
+    return SearchPanel2Layout()
+}
+```
+
+* The `targetState` argument type of `floatingPanelWillEndDragging(_:withVelocity:targetState:)` is changed from `FloatingPanelState` to  `UnsafeMutablePointer<FloatingPanelState>` to modify a target state on demand.
+
+```swift
+func floatingPanelWillEndDragging(_ vc: FloatingPanelController, withVelocity velocity: CGPoint, targetState: UnsafeMutablePointer<FloatingPanelState>) {
+    switch targetState.pointee {
+        case .full:
+          // do something...
+        case .half:
+            if aCondition {
+                targetState.pointee = .tip
+            }
+        default:
+            break
+    }
+}
+```
+
+### Deprecated APIs
+
+* `floatingPanel(_:behaviorFor:)`
+  * Please update `FloatingPanelController.behavior` directly.
+* `floatingPanel(_:shouldRecognizeSimultaneouslyWith:)`
+  * Please use `FloatingPanelController.panGestureRecognizer.delegateProxy`.
+
+## `FloatingPanelLayout`
+
+* `position` property is added to determine a panel position.
+* `initialPosition` is now `initialState`.
+* `supportedPositions` and `insetFor(position:)` are replaced with `anchors` property.
+* `backdropAlphaFor(position:)` is now `backdropAlpha(for:)`.
+
+```swift
+class SearchPanelPadLayout: FloatingPanelLayout {
+    let position: FloatingPanelPosition  = .top
+    let initialState: FloatingPanelState = .tip
+    var anchors: [FloatingPanelState : FloatingPanelLayoutAnchoring] {
+        return [
+            ...
+        ]
+    }
+    func backdropAlpha(for state: FloatingPanelState) -> CGFloat {
+        return 0.3
+    }
+    ...
+}
+```
+
+### New `FloatingPanelLayoutAnchoring` classes
+
+The following objects adopting `FloatingPanelLayoutAnchoring` protocol are added to configure the flexible and explicit layout.
+
+#### `FloatingPanelLayoutAnchor`
+
+This class is used to specify a panel layout using insets from a rectangle area of the superview or safe area.
+
+* `FloatingPanelFullScreenLayout` is replaced with anchors using `.superview` reference guide.
+* `FloatingPanelLayoutAnchor(fractionalInset:edge:referenceGuide:)` lets you lay out a panel at a relative position in a reference rectangle area.
+
+```swift
+// Before:
+class MyPanelLayout: FloatingPanelLayout {
+    var initialPosition: FloatingPanelPosition {
+        return .half
+    }
+
+    func insetFor(position: FloatingPanelPosition) -> CGFloat? {
+        switch position {
+        case .full: return 16.0
+        case .half: return 262.0
+        case .tip: return 44.0
+        case .hidden: return nil
+        }
+    }
+}
+
+// After:
+class MyPanelLayout: FloatingPanelLayout {
+    var position: FloatingPanelPosition = .bottom
+    var initialState: FloatingPanelState { .half }
+    var anchors: [FloatingPanelState : FloatingPanelLayoutAnchoring] {
+        return [
+            .full: FloatingPanelLayoutAnchor(absoluteInset: 16.0, edge: .top, referenceGuide: .safeArea),
+            .half: FloatingPanelLayoutAnchor(fractionalInset: 0.5, edge: .bottom, referenceGuide: .superview),
+            .tip: FloatingPanelLayoutAnchor(absoluteInset: 44.0, edge: .bottom, referenceGuide: .safeArea)
+        ]
+    }
+}
+```
+
+#### `FloatingPanelIntrinsicLayoutAnchor`
+
+This class is used to specify a panel layout using offsets from the intrinsic size layout.
+
+* This replaces `FloatingPanelIntrinsicLayout`.
+* This is also able to configure a fractional layout in the intrinsic size.
+
+```swift
+// Before:
+class MyPanelIntrinsicLayout: FloatingPanelIntrinsicLayout {
+    var initialPosition: FloatingPanelPosition {
+        return .half
+    }
+    func insetFor(position: FloatingPanelPosition) -> CGFloat? {
+        switch position {
+        case .full: return 16.0
+        case .half: return 262.0
+        case .tip: return 44.0
+        case .hidden: return nil
+        }
+    }
+}
+
+// After:
+class MyPanelIntrinsicLayout: FloatingPanelLayout {
+    var position: FloatingPanelPosition = .bottom
+    var initialState: FloatingPanelState { .full }
+    var anchors: [FloatingPanelState : FloatingPanelLayoutAnchoring] {
+        return [
+            .full: FloatingPanelIntrinsicLayoutAnchor(absoluteOffset: 16.0, referenceGuide: .safeArea),
+            .half: FloatingPanelIntrinsicLayoutAnchor(fractionalOffset: 0.5, referenceGuide: .safeArea),
+            .tip: FloatingPanelLayoutAnchor(absoluteInset: 44.0, edge: .bottom, referenceGuide: .safeArea)
+        ]
+    }
+}
+```
+
+### Deprecated APIs
+
+* `.topInteractionBuffer` and `.bottomInteractionBuffer`.
+  * Please control the max/min range of the motion in `floatingPanelDidMove(_:)` delegate method as below.
+
+```swift
+func floatingPanelDidMove(_ fpc: FloatingPanelController) {
+    if fpc.isAttracting == false {
+        let loc = fpc.surfaceLocation
+        let minY = fpc.surfaceLocation(for: .full).y - 6.0
+        let maxY = fpc.surfaceLocation(for: .tip).y + 6.0
+        fpc.surfaceLocation = CGPoint(x: loc.x, y: min(max(loc.y, minY), maxY))
+    }
+}
+```
+
+## `FloatingPanelBehavior`
+
+* `.springDecelerationRate` and `.springResponseTime` properties are added to control the new spring effect of Numeric springing.
+
+### Deprecated APIs
+
+* `addAnimator(_:to:)`, `removeAnimator(_:from:)`
+  * They are moved into `floatingPanel(_:animatorForPresentingTo:)` and  `floatingPanel(_:animatorForDismissingWith:)` of `FloatingPanelControllerDelegate` because they are used for view transitions.
+* `interactionAnimator(_:to:with:)`, `moveAnimator(_:from:to:)`
+  * They are removed because the animators are replaced with the new spring effect.
+* `removalVelocity`, `removalProgress`
+  * They are replaced with `floatingPanel(_:shouldRemoveAt:with:)` of `FloatingPanelControllerDelegate`
+* `removalInteractionAnimator(_:with:)`
+  * It is integrated with `floatingPanel(_:animatorForDismissingWith:)` of `FloatingPanelControllerDelegate`.
+
+## `SurfaceView`
+
+* `SurfaceAppearance` class and `SurfaceView.appearance` property are added to specify the rounding corners, shadows and background color.
+  * `SurfaceView.appearance` property avoids `Ambiguous use of 'cornerRadius'` error, for instance.
+  * `SurfaceAppearance` enables to apply layered box shadows into a surface to materialize it.
+
+```swift
+// Before:
+fpc.surfaceView.cornerRadius = 6.0
+fpc.surfaceView.backgroundColor = .clear
+fpc.surfaceView.shadowHidden = false
+fpc.surfaceView.shadowColor = .black
+fpc.surfaceView.shadowOffset = CGSize(width: 0, height: 16)
+fpc.surfaceView.shadowRadius = 16.0
+
+// After:
+let appearance = SurfaceAppearance()
+appearance.cornerRadius = 8.0
+appearance.backgroundColor = .clear
+
+let shadow = SurfaceAppearance.Shadow()
+shadow.color = .black
+shadow.offset = CGSize(width: 0, height: 16)
+shadow.radius = 16
+shadow.spread = 8
+appearance.shadows = [shadow]
+
+fpc.surfaceView.appearance = appearance
+```
+
+* These properties are changed for the top, left and right positioned panel.
+  * `grabberTopPadding` is now `grabberHandlePadding`.
+  * `topGrabberBarHeight` is now `grabberAreaOffset`.
+  * `grabberHandleWidth` and `grabberHandleHeight` are replaced with `grabberHandleSize`.
+
+## `BackdropView`
+
+* The dismissal action of the backdrop is disabled by default.
+  * You can enable it to set `BackdropView.dismissalTapGestureRecognizer.isEnabled` to `true`.
+
+## `FloatingPanelPanGestureRecognizer`
+
+* `delegateProxy` property is added to intercept the gesture recognizer delegate.
+
+```swift
+func layoutPanelForPad() {
+    fpc.behavior = SearchPaneliPadBehavior()
+    fpc.panGestureRecognizer.delegateProxy = self
+}
+
+func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRequireFailureOf otherGestureRecognizer: UIGestureRecognizer) -> Bool {
+    return false
+}
+```
+
+## Miscellaneous
+
+* `UISpringTimingParameters(decelerationRate:frequencyResponse:initialVelocity:)` initializer is added.
+* The directory structure and file names in the Xcode project changes.

Examples/Maps/Maps.xcodeproj/project.pbxproj

@@ -7,13 +7,17 @@
 	objects = {
 
 /* Begin PBXBuildFile section */
+		543844BD23D2BE2000D5EDE4 /* MapKit.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 543844BC23D2BE2000D5EDE4 /* MapKit.framework */; };
+		549A5F59244673FE0025F312 /* SearchViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 549A5F58244673FE0025F312 /* SearchViewController.swift */; };
+		549D23D2233C77D5008EF4D7 /* FloatingPanel.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 549D23D1233C77D5008EF4D7 /* FloatingPanel.framework */; };
+		549D23D3233C77D5008EF4D7 /* FloatingPanel.framework in Embed Frameworks */ = {isa = PBXBuildFile; fileRef = 549D23D1233C77D5008EF4D7 /* FloatingPanel.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
 		54B5112A216C3D840033A6F3 /* AppDelegate.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54B51129216C3D840033A6F3 /* AppDelegate.swift */; };
 		54B5112C216C3D840033A6F3 /* ViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54B5112B216C3D840033A6F3 /* ViewController.swift */; };
 		54B5112F216C3D840033A6F3 /* Main.storyboard in Resources */ = {isa = PBXBuildFile; fileRef = 54B5112D216C3D840033A6F3 /* Main.storyboard */; };
 		54B51131216C3D860033A6F3 /* Assets.xcassets in Resources */ = {isa = PBXBuildFile; fileRef = 54B51130216C3D860033A6F3 /* Assets.xcassets */; };
 		54B51134216C3D860033A6F3 /* LaunchScreen.storyboard in Resources */ = {isa = PBXBuildFile; fileRef = 54B51132216C3D860033A6F3 /* LaunchScreen.storyboard */; };
-		54B5113F216C407F0033A6F3 /* FloatingPanel.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 54B5113E216C407F0033A6F3 /* FloatingPanel.framework */; };
-		54B51140216C407F0033A6F3 /* FloatingPanel.framework in Embed Frameworks */ = {isa = PBXBuildFile; fileRef = 54B5113E216C407F0033A6F3 /* FloatingPanel.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
+		54E26CB624A989090066C720 /* Utils.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54E26CB524A989090066C720 /* Utils.swift */; };
+		54E26CB824A98E310066C720 /* DetailViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54E26CB724A98E310066C720 /* DetailViewController.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXCopyFilesBuildPhase section */
@@ -23,7 +27,7 @@
 			dstPath = "";
 			dstSubfolderSpec = 10;
 			files = (
-				54B51140216C407F0033A6F3 /* FloatingPanel.framework in Embed Frameworks */,
+				549D23D3233C77D5008EF4D7 /* FloatingPanel.framework in Embed Frameworks */,
 			);
 			name = "Embed Frameworks";
 			runOnlyForDeploymentPostprocessing = 0;
@@ -31,6 +35,9 @@
 /* End PBXCopyFilesBuildPhase section */
 
 /* Begin PBXFileReference section */
+		543844BC23D2BE2000D5EDE4 /* MapKit.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = MapKit.framework; path = System/Library/Frameworks/MapKit.framework; sourceTree = SDKROOT; };
+		549A5F58244673FE0025F312 /* SearchViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SearchViewController.swift; sourceTree = "<group>"; };
+		549D23D1233C77D5008EF4D7 /* FloatingPanel.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; path = FloatingPanel.framework; sourceTree = BUILT_PRODUCTS_DIR; };
 		54B51126216C3D840033A6F3 /* Maps.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = Maps.app; sourceTree = BUILT_PRODUCTS_DIR; };
 		54B51129216C3D840033A6F3 /* AppDelegate.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AppDelegate.swift; sourceTree = "<group>"; };
 		54B5112B216C3D840033A6F3 /* ViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ViewController.swift; sourceTree = "<group>"; };
@@ -38,7 +45,8 @@
 		54B51130216C3D860033A6F3 /* Assets.xcassets */ = {isa = PBXFileReference; lastKnownFileType = folder.assetcatalog; path = Assets.xcassets; sourceTree = "<group>"; };
 		54B51133216C3D860033A6F3 /* Base */ = {isa = PBXFileReference; lastKnownFileType = file.storyboard; name = Base; path = Base.lproj/LaunchScreen.storyboard; sourceTree = "<group>"; };
 		54B51135216C3D860033A6F3 /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
-		54B5113E216C407F0033A6F3 /* FloatingPanel.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; path = FloatingPanel.framework; sourceTree = BUILT_PRODUCTS_DIR; };
+		54E26CB524A989090066C720 /* Utils.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Utils.swift; sourceTree = "<group>"; };
+		54E26CB724A98E310066C720 /* DetailViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DetailViewController.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -46,19 +54,29 @@
 			isa = PBXFrameworksBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
-				54B5113F216C407F0033A6F3 /* FloatingPanel.framework in Frameworks */,
+				543844BD23D2BE2000D5EDE4 /* MapKit.framework in Frameworks */,
+				549D23D2233C77D5008EF4D7 /* FloatingPanel.framework in Frameworks */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
 /* End PBXFrameworksBuildPhase section */
 
 /* Begin PBXGroup section */
+		543844BB23D2BE1F00D5EDE4 /* Frameworks */ = {
+			isa = PBXGroup;
+			children = (
+				543844BC23D2BE2000D5EDE4 /* MapKit.framework */,
+			);
+			name = Frameworks;
+			sourceTree = "<group>";
+		};
 		54B5111D216C3D840033A6F3 = {
 			isa = PBXGroup;
 			children = (
-				54B5113E216C407F0033A6F3 /* FloatingPanel.framework */,
+				549D23D1233C77D5008EF4D7 /* FloatingPanel.framework */,
 				54B51128216C3D840033A6F3 /* Maps */,
 				54B51127216C3D840033A6F3 /* Products */,
+				543844BB23D2BE1F00D5EDE4 /* Frameworks */,
 			);
 			sourceTree = "<group>";
 		};
@@ -75,6 +93,9 @@
 			children = (
 				54B51129216C3D840033A6F3 /* AppDelegate.swift */,
 				54B5112B216C3D840033A6F3 /* ViewController.swift */,
+				549A5F58244673FE0025F312 /* SearchViewController.swift */,
+				54E26CB724A98E310066C720 /* DetailViewController.swift */,
+				54E26CB524A989090066C720 /* Utils.swift */,
 				54B5112D216C3D840033A6F3 /* Main.storyboard */,
 				54B51130216C3D860033A6F3 /* Assets.xcassets */,
 				54B51132216C3D860033A6F3 /* LaunchScreen.storyboard */,
@@ -155,8 +176,11 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				549A5F59244673FE0025F312 /* SearchViewController.swift in Sources */,
 				54B5112C216C3D840033A6F3 /* ViewController.swift in Sources */,
+				54E26CB824A98E310066C720 /* DetailViewController.swift in Sources */,
 				54B5112A216C3D840033A6F3 /* AppDelegate.swift in Sources */,
+				54E26CB624A989090066C720 /* Utils.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -305,14 +329,14 @@
 				CODE_SIGN_STYLE = Automatic;
 				DEVELOPMENT_TEAM = "";
 				INFOPLIST_FILE = Maps/Info.plist;
-				IPHONEOS_DEPLOYMENT_TARGET = 10.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 11.0;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/Frameworks",
 				);
 				PRODUCT_BUNDLE_IDENTIFIER = com.scenee.Maps;
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 4.2;
+				SWIFT_VERSION = 5.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 			};
 			name = Debug;
@@ -324,14 +348,14 @@
 				CODE_SIGN_STYLE = Automatic;
 				DEVELOPMENT_TEAM = "";
 				INFOPLIST_FILE = Maps/Info.plist;
-				IPHONEOS_DEPLOYMENT_TARGET = 10.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 11.0;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/Frameworks",
 				);
 				PRODUCT_BUNDLE_IDENTIFIER = com.scenee.Maps;
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 4.2;
+				SWIFT_VERSION = 5.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 			};
 			name = Release;

Examples/Maps/Maps/AppDelegate.swift

@@ -1,10 +1,4 @@
-//
-//  AppDelegate.swift
-//  Maps
-//
-//  Created by Shin Yamamoto on 2018/10/09.
-//  Copyright © 2018 Shin Yamamoto. All rights reserved.
-//
+// Copyright 2018 the FloatingPanel authors. All rights reserved. MIT license.
 
 import UIKit
 

Examples/Maps/Maps/Base.lproj/Main.storyboard

@@ -1,11 +1,9 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="14313.18" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" useSafeAreas="YES" colorMatched="YES" initialViewController="BYZ-38-t0r">
-    <device id="retina5_9" orientation="portrait">
-        <adaptation id="fullscreen"/>
-    </device>
+<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="17506" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" useSafeAreas="YES" colorMatched="YES" initialViewController="BYZ-38-t0r">
+    <device id="retina5_9" orientation="portrait" appearance="light"/>
     <dependencies>
         <deployment identifier="iOS"/>
-        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="14283.14"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="17505"/>
         <capability name="Safe area layout guides" minToolsVersion="9.0"/>
         <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
     </dependencies>
@@ -27,9 +25,10 @@
                                     <rect key="frame" x="0.0" y="0.0" width="375" height="44"/>
                                     <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                                 </view>
-                                <blurEffect style="light"/>
+                                <blurEffect style="prominent"/>
                             </visualEffectView>
                         </subviews>
+                        <viewLayoutGuide key="safeArea" id="6Tk-OE-BBY"/>
                         <color key="backgroundColor" red="1" green="1" blue="1" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
                         <constraints>
                             <constraint firstItem="5Jw-n2-Cpw" firstAttribute="trailing" secondItem="8bC-Xf-vdC" secondAttribute="trailing" id="1Fg-Be-qfh"/>
@@ -41,7 +40,6 @@
                             <constraint firstItem="6Tk-OE-BBY" firstAttribute="top" secondItem="d9i-3g-8Ja" secondAttribute="bottom" id="Y1G-hr-aEX"/>
                             <constraint firstItem="d9i-3g-8Ja" firstAttribute="leading" secondItem="6Tk-OE-BBY" secondAttribute="leading" id="diB-Ij-HN3"/>
                         </constraints>
-                        <viewLayoutGuide key="safeArea" id="6Tk-OE-BBY"/>
                     </view>
                     <connections>
                         <outlet property="mapView" destination="5Jw-n2-Cpw" id="WVC-rU-mLe"/>
@@ -51,18 +49,18 @@
             </objects>
             <point key="canvasLocation" x="136.80000000000001" y="133.00492610837438"/>
         </scene>
-        <!--Search Panel View Controller-->
+        <!--Search View Controller-->
         <scene sceneID="kXy-li-p3C">
             <objects>
-                <viewController storyboardIdentifier="SearchPanel" useStoryboardIdentifierAsRestorationIdentifier="YES" id="0S1-Lk-JgE" customClass="SearchPanelViewController" customModule="Maps" customModuleProvider="target" sceneMemberID="viewController">
+                <viewController storyboardIdentifier="SearchViewController" useStoryboardIdentifierAsRestorationIdentifier="YES" id="0S1-Lk-JgE" customClass="SearchViewController" customModule="Maps" customModuleProvider="target" sceneMemberID="viewController">
                     <view key="view" contentMode="scaleToFill" id="Ncl-E9-yRn">
                         <rect key="frame" x="0.0" y="0.0" width="375" height="812"/>
                         <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                         <subviews>
                             <visualEffectView opaque="NO" contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="Ye3-uU-bq3">
-                                <rect key="frame" x="0.0" y="0.0" width="375" height="900"/>
+                                <rect key="frame" x="0.0" y="0.0" width="375" height="812"/>
                                 <view key="contentView" opaque="NO" clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="center" insetsLayoutMarginsFromSafeArea="NO" id="ED1-gT-FBj">
-                                    <rect key="frame" x="0.0" y="0.0" width="375" height="900"/>
+                                    <rect key="frame" x="0.0" y="0.0" width="375" height="812"/>
                                     <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                                     <subviews>
                                         <searchBar contentMode="redraw" searchBarStyle="minimal" translatesAutoresizingMaskIntoConstraints="NO" id="Zcj-SE-gb8">
@@ -70,7 +68,7 @@
                                             <textInputTraits key="textInputTraits"/>
                                         </searchBar>
                                         <tableView clipsSubviews="YES" contentMode="scaleToFill" alwaysBounceVertical="YES" showsHorizontalScrollIndicator="NO" showsVerticalScrollIndicator="NO" dataMode="prototypes" style="plain" separatorStyle="default" rowHeight="-1" estimatedRowHeight="-1" sectionHeaderHeight="28" sectionFooterHeight="28" translatesAutoresizingMaskIntoConstraints="NO" id="D7r-re-InH">
-                                            <rect key="frame" x="0.0" y="66" width="375" height="748"/>
+                                            <rect key="frame" x="0.0" y="66" width="375" height="746"/>
                                             <color key="backgroundColor" white="0.0" alpha="0.0" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
                                             <view key="tableHeaderView" contentMode="scaleToFill" id="u28-LY-hIh" customClass="SearchHeaderView" customModule="Maps" customModuleProvider="target">
                                                 <rect key="frame" x="0.0" y="0.0" width="375" height="116"/>
@@ -173,7 +171,7 @@
                                                     <rect key="frame" x="0.0" y="144" width="375" height="70"/>
                                                     <autoresizingMask key="autoresizingMask"/>
                                                     <tableViewCellContentView key="contentView" opaque="NO" clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="center" insetsLayoutMarginsFromSafeArea="NO" tableViewCell="LzC-B9-Adb" id="evr-60-laS">
-                                                        <rect key="frame" x="0.0" y="0.0" width="375" height="69.666666666666671"/>
+                                                        <rect key="frame" x="0.0" y="0.0" width="375" height="70"/>
                                                         <autoresizingMask key="autoresizingMask"/>
                                                         <subviews>
                                                             <imageView userInteractionEnabled="NO" contentMode="scaleToFill" horizontalHuggingPriority="251" verticalHuggingPriority="251" image="like" translatesAutoresizingMaskIntoConstraints="NO" id="GEk-yE-lLq">
@@ -185,7 +183,7 @@
                                                                 </constraints>
                                                             </imageView>
                                                             <stackView opaque="NO" contentMode="scaleToFill" axis="vertical" distribution="fillEqually" spacing="2" translatesAutoresizingMaskIntoConstraints="NO" id="Gfl-Oy-rsy">
-                                                                <rect key="frame" x="57" y="11.999999999999996" width="303" height="45.666666666666657"/>
+                                                                <rect key="frame" x="57" y="12" width="303" height="46"/>
                                                                 <subviews>
                                                                     <label opaque="NO" userInteractionEnabled="NO" tag="1" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Favorites" textAlignment="natural" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="Spf-8L-Ne6">
                                                                         <rect key="frame" x="0.0" y="0.0" width="303" height="22"/>
@@ -194,7 +192,7 @@
                                                                         <nil key="highlightedColor"/>
                                                                     </label>
                                                                     <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="0 Places" textAlignment="natural" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="gyo-3V-7U8">
-                                                                        <rect key="frame" x="0.0" y="24" width="303" height="21.666666666666671"/>
+                                                                        <rect key="frame" x="0.0" y="24" width="303" height="22"/>
                                                                         <fontDescription key="fontDescription" type="system" pointSize="13"/>
                                                                         <color key="textColor" red="0.57647058819999997" green="0.57647058819999997" blue="0.57647058819999997" alpha="1" colorSpace="calibratedRGB"/>
                                                                         <nil key="highlightedColor"/>
@@ -227,22 +225,22 @@
                                         <constraint firstAttribute="trailing" secondItem="D7r-re-InH" secondAttribute="trailing" id="BES-GA-Btp"/>
                                         <constraint firstItem="D7r-re-InH" firstAttribute="leading" secondItem="ED1-gT-FBj" secondAttribute="leading" id="UTe-YL-17h"/>
                                         <constraint firstItem="Zcj-SE-gb8" firstAttribute="top" secondItem="ED1-gT-FBj" secondAttribute="top" constant="6" id="apU-Pd-PEO"/>
-                                        <constraint firstAttribute="bottom" secondItem="D7r-re-InH" secondAttribute="bottom" constant="86" id="vfS-Lx-TXz"/>
+                                        <constraint firstAttribute="bottom" secondItem="D7r-re-InH" secondAttribute="bottom" id="vfS-Lx-TXz"/>
                                         <constraint firstItem="D7r-re-InH" firstAttribute="top" secondItem="Zcj-SE-gb8" secondAttribute="bottom" constant="4" id="vro-cd-B9c"/>
                                         <constraint firstItem="Zcj-SE-gb8" firstAttribute="leading" secondItem="ED1-gT-FBj" secondAttribute="leading" id="wMb-L2-Z0W"/>
                                     </constraints>
                                 </view>
-                                <blurEffect style="extraLight"/>
+                                <blurEffect style="prominent"/>
                             </visualEffectView>
                         </subviews>
+                        <viewLayoutGuide key="safeArea" id="G74-X7-Za8"/>
                         <color key="backgroundColor" white="0.0" alpha="0.0" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
                         <constraints>
                             <constraint firstItem="Ye3-uU-bq3" firstAttribute="leading" secondItem="G74-X7-Za8" secondAttribute="leading" id="Kr2-sU-ZWZ"/>
-                            <constraint firstItem="Ye3-uU-bq3" firstAttribute="bottom" secondItem="Ncl-E9-yRn" secondAttribute="bottom" constant="88" id="aWM-s3-3o4"/>
+                            <constraint firstItem="Ye3-uU-bq3" firstAttribute="bottom" secondItem="Ncl-E9-yRn" secondAttribute="bottom" id="aWM-s3-3o4"/>
                             <constraint firstItem="Ye3-uU-bq3" firstAttribute="trailing" secondItem="G74-X7-Za8" secondAttribute="trailing" id="fEL-8y-Acc"/>
                             <constraint firstItem="Ye3-uU-bq3" firstAttribute="top" secondItem="Ncl-E9-yRn" secondAttribute="top" id="w77-ba-FrJ"/>
                         </constraints>
-                        <viewLayoutGuide key="safeArea" id="G74-X7-Za8"/>
                     </view>
                     <connections>
                         <outlet property="searchBar" destination="Zcj-SE-gb8" id="BH7-Gy-RG5"/>
@@ -254,6 +252,44 @@
             </objects>
             <point key="canvasLocation" x="789.60000000000002" y="133.5832083958021"/>
         </scene>
+        <!--Detail View Controller-->
+        <scene sceneID="5tH-Ya-PzB">
+            <objects>
+                <viewController storyboardIdentifier="DetailViewController" id="Tp2-MF-IFz" customClass="DetailViewController" customModule="Maps" customModuleProvider="target" sceneMemberID="viewController">
+                    <view key="view" contentMode="scaleToFill" id="FmO-AT-4Y7">
+                        <rect key="frame" x="0.0" y="0.0" width="375" height="812"/>
+                        <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
+                        <subviews>
+                            <visualEffectView opaque="NO" contentMode="scaleToFill" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="c3d-2e-0b1">
+                                <rect key="frame" x="0.0" y="0.0" width="375" height="812"/>
+                                <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
+                                <view key="contentView" opaque="NO" clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="center" insetsLayoutMarginsFromSafeArea="NO" id="9fL-a5-0LS">
+                                    <rect key="frame" x="0.0" y="0.0" width="375" height="812"/>
+                                    <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
+                                    <subviews>
+                                        <tableView clipsSubviews="YES" contentMode="scaleToFill" alwaysBounceVertical="YES" showsHorizontalScrollIndicator="NO" showsVerticalScrollIndicator="NO" dataMode="prototypes" style="plain" separatorStyle="default" rowHeight="-1" estimatedRowHeight="-1" sectionHeaderHeight="28" sectionFooterHeight="28" translatesAutoresizingMaskIntoConstraints="NO" id="kP7-56-wlG">
+                                            <rect key="frame" x="0.0" y="0.0" width="375" height="812"/>
+                                            <color key="backgroundColor" white="0.0" alpha="0.0" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
+                                        </tableView>
+                                    </subviews>
+                                    <constraints>
+                                        <constraint firstItem="kP7-56-wlG" firstAttribute="leading" secondItem="9fL-a5-0LS" secondAttribute="leading" id="6gf-GO-cnv"/>
+                                        <constraint firstAttribute="bottom" secondItem="kP7-56-wlG" secondAttribute="bottom" id="WrH-tz-UQF"/>
+                                        <constraint firstItem="kP7-56-wlG" firstAttribute="top" secondItem="9fL-a5-0LS" secondAttribute="top" id="aJk-bz-lVc"/>
+                                        <constraint firstAttribute="trailing" secondItem="kP7-56-wlG" secondAttribute="trailing" id="sE0-9V-Rot"/>
+                                    </constraints>
+                                </view>
+                                <blurEffect style="extraLight"/>
+                            </visualEffectView>
+                        </subviews>
+                        <viewLayoutGuide key="safeArea" id="ctv-Dd-JUc"/>
+                        <color key="backgroundColor" white="0.0" alpha="0.0" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
+                    </view>
+                </viewController>
+                <placeholder placeholderIdentifier="IBFirstResponder" id="EDp-D2-xcT" userLabel="First Responder" customClass="UIResponder" sceneMemberID="firstResponder"/>
+            </objects>
+            <point key="canvasLocation" x="1447" y="133"/>
+        </scene>
     </scenes>
     <resources>
         <image name="food" width="60" height="60"/>

Examples/Maps/Maps/DetailViewController.swift

@@ -0,0 +1,7 @@
+// Copyright 2018 the FloatingPanel authors. All rights reserved. MIT license.
+
+import UIKit
+
+class DetailViewController: UIViewController {
+    var item: LocationItem?
+}

Examples/Maps/Maps/SearchViewController.swift

@@ -0,0 +1,184 @@
+// Copyright 2018 the FloatingPanel authors. All rights reserved. MIT license.
+
+import UIKit
+
+// MARK: - UITableViewDelegate
+
+extension ViewController: UITableViewDelegate {
+    func setUpSearchView() {
+        searchVC.loadViewIfNeeded()
+        searchVC.tableView.delegate = self
+        searchVC.searchBar.placeholder = "Search for a place or address"
+        let isPad = (traitCollection.userInterfaceIdiom == .pad)
+        searchVC.items = [
+            .init(mark: "mark", title: "Marked Location" + (isPad ? " (Left panel)" : ""), subtitle: "Golden Gate Bridge, San Francisco"),
+            .init(mark: "mark", title: "Marked Location"  + (isPad ? " (Right panel)" : ""), subtitle: "San Francisco Museum of Modern Art"),
+        ]
+        searchVC.items.append(contentsOf: (0...98).map {
+            .init(mark: "like", title: "Favorites", subtitle: "\($0) Places")
+        })
+    }
+
+    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
+        tableView.deselectRow(at: indexPath, animated: true)
+
+        deactivate(searchBar: searchVC.searchBar)
+
+        // Show a detail panel
+        switch indexPath.row {
+        case 0:
+            detailVC.item = searchVC.items[safe: 0]
+
+            // Show detail vc in the left positioned panel
+            switch traitCollection.userInterfaceIdiom {
+            case .pad:
+                detailFpc.layout = DetailPanelPadLeftLayout()
+                detailFpc.surfaceView.containerMargins = UIEdgeInsets(top: 0.0, left: 16.0, bottom: 0.0, right: 0.0)
+            default:
+                detailFpc.layout = DetailPanelPhoneLayout()
+                detailFpc.surfaceView.containerMargins = .zero
+            }
+            detailFpc.addPanel(toParent: self, animated: true)
+        case 1:
+            detailVC.item = searchVC.items[safe: 1]
+
+            // Show detail vc in the right positioned panel
+            switch traitCollection.userInterfaceIdiom {
+            case .pad:
+                detailFpc.layout = DetailPanelPadRightLayout()
+                detailFpc.surfaceView.containerMargins = UIEdgeInsets(top: 0.0, left: 0.0, bottom: 0.0, right: 16.0)
+            default:
+                detailFpc.layout = DetailPanelPhoneLayout()
+                detailFpc.surfaceView.containerMargins = .zero
+            }
+            detailFpc.addPanel(toParent: self, animated: true)
+        default:
+            break
+        }
+    }
+}
+
+// MARK: - Models
+
+struct LocationItem {
+    let mark: String
+    let title: String
+    let subtitle: String
+
+    init(mark: String, title: String, subtitle: String) {
+        self.mark = mark
+        self.title = title
+        self.subtitle = subtitle
+    }
+}
+
+// MARK: -
+
+class SearchViewController: UIViewController, UITableViewDataSource {
+    @IBOutlet weak var tableView: UITableView!
+    @IBOutlet weak var searchBar: UISearchBar!
+    @IBOutlet weak var visualEffectView: UIVisualEffectView!
+
+    var items: [LocationItem] = []
+
+    // For iOS 10 only
+    private lazy var shadowLayer: CAShapeLayer = CAShapeLayer()
+
+    override func viewDidLoad() {
+        super.viewDidLoad()
+        tableView.dataSource = self
+        searchBar.setSearchText(fontSize: 15.0)
+
+        hideHeader(animated: false)
+    }
+
+    override func viewDidLayoutSubviews() {
+        super.viewDidLayoutSubviews()
+        if #available(iOS 11, *) {
+        } else {
+            // Exmaple: Add rounding corners on iOS 10
+            visualEffectView.layer.cornerRadius = 9.0
+            visualEffectView.clipsToBounds = true
+
+            // Exmaple: Add shadow manually on iOS 10
+            view.layer.insertSublayer(shadowLayer, at: 0)
+            let rect = visualEffectView.frame
+            let path = UIBezierPath(roundedRect: rect,
+                                    byRoundingCorners: [.topLeft, .topRight],
+                                    cornerRadii: CGSize(width: 9.0, height: 9.0))
+            shadowLayer.frame = visualEffectView.frame
+            shadowLayer.shadowPath = path.cgPath
+            shadowLayer.shadowColor = UIColor.black.cgColor
+            shadowLayer.shadowOffset = CGSize(width: 0.0, height: 1.0)
+            shadowLayer.shadowOpacity = 0.2
+            shadowLayer.shadowRadius = 3.0
+        }
+    }
+
+    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
+        return items.count
+    }
+
+    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
+        let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath)
+        if let cell = cell as? SearchCell, let item = items[safe: indexPath.row] {
+            cell.iconImageView.image = UIImage(named: item.mark)
+            cell.titleLabel.text = item.title
+            cell.subTitleLabel.text = item.subtitle
+        }
+        return cell
+    }
+
+    func showHeader(animated: Bool) {
+        changeHeader(height: 116.0, aniamted: animated)
+    }
+
+    func hideHeader(animated: Bool) {
+        changeHeader(height: 0.0, aniamted: animated)
+    }
+
+    private func changeHeader(height: CGFloat, aniamted: Bool) {
+        guard let headerView = tableView.tableHeaderView, headerView.bounds.height != height else { return }
+        if aniamted == false {
+            updateHeader(height: height)
+            return
+        }
+        tableView.beginUpdates()
+        UIView.animate(withDuration: 0.25) {
+            self.updateHeader(height: height)
+        }
+        tableView.endUpdates()
+    }
+
+    private func updateHeader(height: CGFloat) {
+        guard let headerView = tableView.tableHeaderView else { return }
+        var frame = headerView.frame
+        frame.size.height = height
+        self.tableView.tableHeaderView?.frame = frame
+    }
+}
+
+class SearchCell: UITableViewCell {
+    @IBOutlet weak var iconImageView: UIImageView!
+    @IBOutlet weak var titleLabel: UILabel!
+    @IBOutlet weak var subTitleLabel: UILabel!
+}
+
+class SearchHeaderView: UIView {
+    required init?(coder aDecoder: NSCoder) {
+        super.init(coder: aDecoder)
+        self.clipsToBounds = true
+    }
+}
+
+extension UISearchBar {
+    func setSearchText(fontSize: CGFloat) {
+        if #available(iOS 13, *) {
+            let font = searchTextField.font
+            searchTextField.font = font?.withSize(fontSize)
+        } else {
+            let textField = value(forKey: "_searchField") as! UITextField
+            textField.font = textField.font?.withSize(fontSize)
+        }
+    }
+}

Examples/Maps/Maps/Utils.swift

@@ -0,0 +1,19 @@
+// Copyright 2018 the FloatingPanel authors. All rights reserved. MIT license.
+
+import UIKit
+
+extension Collection {
+    subscript (safe index: Index) -> Element? {
+        return indices.contains(index) ? self[index] : nil
+    }
+}
+
+extension UIViewController {
+    var isLandscape: Bool {
+        if #available(iOS 13.0, *) {
+            return view.window?.windowScene?.interfaceOrientation.isLandscape ?? false
+        } else {
+            return UIApplication.shared.statusBarOrientation.isLandscape
+        }
+    }
+}

Examples/Maps/Maps/ViewController.swift

@@ -1,42 +1,51 @@
-//
-//  Copyright © 2018 Shin Yamamoto. All rights reserved.
-//
+// Copyright 2018 the FloatingPanel authors. All rights reserved. MIT license.
 
 import UIKit
 import MapKit
 import FloatingPanel
 
-class ViewController: UIViewController, MKMapViewDelegate, UISearchBarDelegate, FloatingPanelControllerDelegate {
-    var fpc: FloatingPanelController!
-    var searchVC: SearchPanelViewController!
+class ViewController: UIViewController {
+    typealias PanelDelegate = FloatingPanelControllerDelegate & UIGestureRecognizerDelegate
+
+    // Search Panel
+    lazy var fpc = FloatingPanelController()
+    lazy var fpcDelegate: PanelDelegate =
+        (traitCollection.userInterfaceIdiom == .pad) ? SearchPanelPadDelegate(owner: self) : SearchPanelPhoneDelegate(owner: self)
+    lazy var searchVC =
+        storyboard?.instantiateViewController(withIdentifier: "SearchViewController") as! SearchViewController
+
+    // Detail Panel
+    lazy var detailFpc = FloatingPanelController()
+    lazy var detailFpcDelegate: PanelDelegate =
+        (traitCollection.userInterfaceIdiom == .pad) ? DetailPanelPadDelegate(owner: self) : DetailPanelPhoneDelegate(owner: self)
+    lazy var detailVC =
+        storyboard?.instantiateViewController(withIdentifier: "DetailViewController") as! DetailViewController
 
     @IBOutlet weak var mapView: MKMapView!
 
     override func viewDidLoad() {
         super.viewDidLoad()
-        // Do any additional setup after loading the view, typically from a nib.
-        // Initialize FloatingPanelController
-        fpc = FloatingPanelController()
-        fpc.delegate = self
-
-        // Initialize FloatingPanelController and add the view
-        fpc.surfaceView.backgroundColor = .clear
-        fpc.surfaceView.cornerRadius = 9.0
-        fpc.surfaceView.shadowHidden = false
-
-        searchVC = storyboard?.instantiateViewController(withIdentifier: "SearchPanel") as? SearchPanelViewController
-
-        // Set a content view controller
+        fpc.contentMode = .fitToBounds
+        fpc.delegate = fpcDelegate
         fpc.set(contentViewController: searchVC)
         fpc.track(scrollView: searchVC.tableView)
 
+        detailFpc.isRemovalInteractionEnabled = true
+        detailFpc.set(contentViewController: detailVC)
+
+        switch traitCollection.userInterfaceIdiom {
+        case .pad:
+            layoutPanelForPad()
+        default:
+            layoutPanelForPhone()
+        }
+
         setupMapView()
+        setUpSearchView()
     }
 
     override func viewDidAppear(_ animated: Bool) {
         super.viewDidAppear(animated)
-        //  Add FloatingPanel to a view with animation.
-        fpc.addPanel(toParent: self, animated: true)
 
         // Must be here
         searchVC.searchBar.delegate = self
@@ -47,6 +56,338 @@ class ViewController: UIViewController, MKMapViewDelegate, UISearchBarDelegate,
         teardownMapView()
     }
 
+    func layoutPanelForPad() {
+        fpc.behavior = SearchPaneliPadBehavior()
+        fpc.panGestureRecognizer.delegateProxy = fpcDelegate
+
+        // Not use addPanel(toParent:) because of the Auto Layout configuration of fpc.view.
+        view.addSubview(fpc.view)
+        addChild(fpc)
+        fpc.view.frame = view.bounds // Needed for a correct safe area configuration
+        fpc.view.translatesAutoresizingMaskIntoConstraints = false
+        NSLayoutConstraint.activate([
+            fpc.view.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 0.0),
+            fpc.view.leftAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leftAnchor, constant: 0.0 ),
+            fpc.view.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: 0.0),
+            fpc.view.rightAnchor.constraint(equalTo: view.safeAreaLayoutGuide.rightAnchor, constant: 0.0),
+        ])
+        fpc.show(animated: false) { [weak self] in
+            guard let self = self else { return }
+            self.didMove(toParent: self)
+        }
+
+        fpc.setAppearanceForPad()
+        detailFpc.setAppearanceForPad()
+    }
+
+    func layoutPanelForPhone() {
+        fpc.track(scrollView: searchVC.tableView) // Only track the tabvle view on iPhone
+        fpc.addPanel(toParent: self, animated: true)
+        fpc.setAppearanceForPhone()
+        detailFpc.setAppearanceForPhone()
+    }
+}
+
+extension FloatingPanelController {
+    func setAppearanceForPhone() {
+        let appearance = SurfaceAppearance()
+        if #available(iOS 13.0, *) {
+            appearance.cornerCurve = .continuous
+        }
+        appearance.cornerRadius = 8.0
+        appearance.backgroundColor = .clear
+        surfaceView.appearance = appearance
+    }
+
+    func setAppearanceForPad() {
+        view.clipsToBounds = false
+        let appearance = SurfaceAppearance()
+        appearance.cornerRadius = 8.0
+        let shadow = SurfaceAppearance.Shadow()
+        shadow.color = UIColor.black
+        shadow.offset = CGSize(width: 0, height: 16)
+        shadow.radius = 16
+        shadow.spread = 8
+        appearance.shadows = [shadow]
+        appearance.backgroundColor = .clear
+        surfaceView.appearance = appearance
+    }
+}
+
+// MARK: - UISearchBarDelegate
+
+extension ViewController: UISearchBarDelegate {
+    func activate(searchBar: UISearchBar) {
+        searchBar.showsCancelButton = true
+        searchVC.showHeader(animated: true)
+        searchVC.tableView.alpha = 1.0
+        detailVC.dismiss(animated: true, completion: nil)
+    }
+    func deactivate(searchBar: UISearchBar) {
+        searchBar.resignFirstResponder()
+        searchBar.showsCancelButton  = false
+        searchVC.hideHeader(animated: true)
+    }
+
+    func searchBarCancelButtonClicked(_ searchBar: UISearchBar) {
+        deactivate(searchBar: searchBar)
+        UIView.animate(withDuration: 0.25) {
+            self.fpc.move(to: .half, animated: false)
+        }
+    }
+
+    func searchBarTextDidBeginEditing(_ searchBar: UISearchBar) {
+        activate(searchBar: searchBar)
+        UIView.animate(withDuration: 0.25) { [weak self] in
+            self?.fpc.move(to: .full, animated: false)
+        }
+    }
+}
+
+// MARK: - iPhone
+
+class SearchPanelPhoneDelegate: NSObject, FloatingPanelControllerDelegate, UIGestureRecognizerDelegate {
+    unowned let owner: ViewController
+
+    init(owner: ViewController) {
+        self.owner = owner
+    }
+
+    func floatingPanel(_ vc: FloatingPanelController, layoutFor newCollection: UITraitCollection) -> FloatingPanelLayout {
+        switch newCollection.verticalSizeClass {
+        case .compact:
+            let appearance = vc.surfaceView.appearance
+            appearance.borderWidth = 1.0 / owner.traitCollection.displayScale
+            appearance.borderColor = UIColor.black.withAlphaComponent(0.2)
+            vc.surfaceView.appearance = appearance
+            return SearchPanelLandscapeLayout()
+        default:
+            let appearance = vc.surfaceView.appearance
+            appearance.borderWidth = 0.0
+            appearance.borderColor = nil
+            vc.surfaceView.appearance = appearance
+            return FloatingPanelBottomLayout()
+        }
+    }
+
+    func floatingPanelDidMove(_ vc: FloatingPanelController) {
+        debugPrint("surfaceLocation: ", vc.surfaceLocation)
+        let loc = vc.surfaceLocation
+
+        if vc.isAttracting == false {
+            let minY = vc.surfaceLocation(for: .full).y - 6.0
+            let maxY = vc.surfaceLocation(for: .tip).y + 6.0
+            vc.surfaceLocation = CGPoint(x: loc.x, y: min(max(loc.y, minY), maxY))
+        }
+
+        let tipY = vc.surfaceLocation(for: .tip).y
+        if loc.y > tipY - 44.0 {
+            let progress = max(0.0, min((tipY  - loc.y) / 44.0, 1.0))
+            owner.searchVC.tableView.alpha = progress
+        } else {
+            owner.searchVC.tableView.alpha = 1.0
+        }
+        debugPrint("NearbyState : ",vc.nearbyState)
+    }
+
+    func floatingPanelWillBeginDragging(_ vc: FloatingPanelController) {
+        if vc.state == .full {
+            owner.searchVC.searchBar.showsCancelButton = false
+            owner.searchVC.searchBar.resignFirstResponder()
+        }
+    }
+
+    func floatingPanelWillEndDragging(_ vc: FloatingPanelController, withVelocity velocity: CGPoint, targetState: UnsafeMutablePointer<FloatingPanelState>) {
+        if targetState.pointee != .full {
+            owner.searchVC.hideHeader(animated: true)
+        }
+        if targetState.pointee == .tip {
+            vc.contentMode = .static
+        }
+    }
+
+    func floatingPanelDidEndAttracting(_ fpc: FloatingPanelController) {
+        fpc.contentMode = .fitToBounds
+    }
+}
+
+class SearchPanelLandscapeLayout: FloatingPanelLayout {
+    let position: FloatingPanelPosition  = .bottom
+    let initialState: FloatingPanelState = .tip
+    var anchors: [FloatingPanelState : FloatingPanelLayoutAnchoring] {
+        return [
+            .full: FloatingPanelLayoutAnchor(absoluteInset: 16.0, edge: .top, referenceGuide: .safeArea),
+            .tip: FloatingPanelLayoutAnchor(absoluteInset: 69.0, edge: .bottom, referenceGuide: .safeArea),
+        ]
+    }
+    func prepareLayout(surfaceView: UIView, in view: UIView) -> [NSLayoutConstraint] {
+        if #available(iOS 11.0, *) {
+            return [
+                surfaceView.leftAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leftAnchor, constant: 8.0),
+                surfaceView.widthAnchor.constraint(equalToConstant: 291),
+            ]
+        } else {
+            return [
+                surfaceView.leftAnchor.constraint(equalTo: view.leftAnchor, constant: 8.0),
+                surfaceView.widthAnchor.constraint(equalToConstant: 291),
+            ]
+        }
+    }
+    func backdropAlpha(for state: FloatingPanelState) -> CGFloat {
+        return 0.0
+    }
+}
+
+class DetailPanelPhoneDelegate: NSObject, FloatingPanelControllerDelegate, UIGestureRecognizerDelegate {
+    unowned let owner: ViewController
+
+    init(owner: ViewController) {
+        self.owner = owner
+    }
+}
+
+class DetailPanelPhoneLayout: FloatingPanelLayout {
+    let position: FloatingPanelPosition  = .bottom
+    var anchors: [FloatingPanelState : FloatingPanelLayoutAnchoring] {
+        return [
+            .full: FloatingPanelLayoutAnchor(fractionalInset: 0.5, edge: .bottom, referenceGuide: .safeArea),
+        ]
+    }
+    let initialState: FloatingPanelState = .full
+    func backdropAlpha(for state: FloatingPanelState) -> CGFloat {
+        return 0.0
+    }
+}
+
+// MARK: - iPad
+
+class SearchPanelPadDelegate: NSObject, FloatingPanelControllerDelegate, UIGestureRecognizerDelegate {
+    unowned let owner: ViewController
+
+    init(owner: ViewController) {
+        self.owner = owner
+    }
+
+    func floatingPanel(_ fpc: FloatingPanelController, layoutFor newCollection: UITraitCollection) -> FloatingPanelLayout {
+        if newCollection.horizontalSizeClass == .compact {
+            fpc.surfaceView.containerMargins = .zero
+            return FloatingPanelBottomLayout()
+        }
+        fpc.surfaceView.containerMargins = UIEdgeInsets(top: .leastNonzeroMagnitude, // For top left/right rounding corners
+                                                        left: 16,
+                                                        bottom: 0.0,
+                                                        right: 0.0)
+        return SearchPanelPadLayout()
+    }
+
+    func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRequireFailureOf otherGestureRecognizer: UIGestureRecognizer) -> Bool {
+        return false
+    }
+
+    func floatingPanelWillBeginDragging(_ vc: FloatingPanelController) {
+        if vc.state == .full {
+            owner.searchVC.searchBar.showsCancelButton = false
+            owner.searchVC.searchBar.resignFirstResponder()
+        }
+    }
+
+    func floatingPanelWillEndDragging(_ vc: FloatingPanelController, withVelocity velocity: CGPoint, targetState: UnsafeMutablePointer<FloatingPanelState>) {
+        if targetState.pointee != .full {
+            owner.searchVC.hideHeader(animated: true)
+        }
+    }
+}
+
+class SearchPanelPadLayout: FloatingPanelLayout {
+    let position: FloatingPanelPosition  = .top
+    let initialState: FloatingPanelState = .tip
+    var anchors: [FloatingPanelState : FloatingPanelLayoutAnchoring] {
+        return [
+            .tip: FloatingPanelLayoutAnchor(absoluteInset: 80.0, edge: .top, referenceGuide: .superview),
+            .half: FloatingPanelLayoutAnchor(absoluteInset: 200.0, edge: .top, referenceGuide: .superview),
+            .full: FloatingPanelLayoutAnchor(absoluteInset: 60.0, edge: .bottom, referenceGuide: .superview),
+        ]
+    }
+    func backdropAlpha(for state: FloatingPanelState) -> CGFloat {
+        return 0.0
+    }
+    func prepareLayout(surfaceView: UIView, in view: UIView) -> [NSLayoutConstraint] {
+        return [
+            surfaceView.leftAnchor.constraint(equalTo: view.leftAnchor),
+            surfaceView.widthAnchor.constraint(equalToConstant: 375),
+        ]
+    }
+}
+
+class SearchPaneliPadBehavior: FloatingPanelBehavior {
+    var springDecelerationRate: CGFloat {
+        return UIScrollView.DecelerationRate.fast.rawValue - 0.003
+    }
+    var springResponseTime: CGFloat {
+        return 0.3
+    }
+    var momentumProjectionRate: CGFloat {
+        return UIScrollView.DecelerationRate.fast.rawValue
+    }
+    func shouldProjectMomentum(_ fpc: FloatingPanelController, to proposedTargetPosition: FloatingPanelState) -> Bool {
+        return true
+    }
+}
+
+class DetailPanelPadDelegate: NSObject, FloatingPanelControllerDelegate, UIGestureRecognizerDelegate {
+    unowned let owner: ViewController
+
+    init(owner: ViewController) {
+        self.owner = owner
+    }
+
+    func floatingPanel(_ fpc: FloatingPanelController, layoutFor newCollection: UITraitCollection) -> FloatingPanelLayout {
+        if newCollection.horizontalSizeClass == .compact {
+            fpc.surfaceView.containerMargins = .zero
+            return FloatingPanelBottomLayout()
+        }
+        if let item = owner.detailVC.item, item.title.contains("Right") {
+            fpc.surfaceView.containerMargins = UIEdgeInsets(top: 0.0, left: 0.0, bottom: 0.0, right: .leastNonzeroMagnitude)
+            return DetailPanelPadRightLayout()
+        }
+        fpc.surfaceView.containerMargins = UIEdgeInsets(top: 0.0, left: .leastNonzeroMagnitude, bottom: 0.0, right: 0.0)
+        return DetailPanelPadLeftLayout()
+    }
+
+    func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRequireFailureOf otherGestureRecognizer: UIGestureRecognizer) -> Bool {
+        return false
+    }
+}
+
+class DetailPanelPadLeftLayout: FloatingPanelLayout {
+    let position: FloatingPanelPosition  = .left
+    var anchors: [FloatingPanelState : FloatingPanelLayoutAnchoring] {
+        return [
+            .full: FloatingPanelLayoutAnchor(absoluteInset: 375, edge: .left, referenceGuide: .superview)
+        ]
+    }
+    let initialState: FloatingPanelState = .full
+    func backdropAlpha(for state: FloatingPanelState) -> CGFloat {
+        return 0.0
+    }
+}
+
+class DetailPanelPadRightLayout: FloatingPanelLayout {
+    let position: FloatingPanelPosition  = .right
+    var anchors: [FloatingPanelState : FloatingPanelLayoutAnchoring] {
+        return [
+            .full: FloatingPanelLayoutAnchor(absoluteInset: 375, edge: .right, referenceGuide: .superview)
+        ]
+    }
+    let initialState: FloatingPanelState = .full
+    func backdropAlpha(for state: FloatingPanelState) -> CGFloat {
+        return 0.0
+    }
+}
+
+// MARK: - MKMapViewDelegate
+
+extension ViewController: MKMapViewDelegate {
     func setupMapView() {
         let center = CLLocationCoordinate2D(latitude: 37.623198015869235,
                                             longitude: -122.43066818432008)
@@ -64,191 +405,4 @@ class ViewController: UIViewController, MKMapViewDelegate, UISearchBarDelegate,
         mapView.delegate = nil
         mapView = nil
     }
-
-    // MARK: UISearchBarDelegate
-
-    func searchBarCancelButtonClicked(_ searchBar: UISearchBar) {
-        searchBar.resignFirstResponder()
-        searchBar.showsCancelButton  = false
-        searchVC.hideHeader()
-        fpc.move(to: .half, animated: true)
-    }
-
-    func searchBarTextDidBeginEditing(_ searchBar: UISearchBar) {
-        searchBar.showsCancelButton = true
-        searchVC.showHeader()
-        searchVC.tableView.alpha = 1.0
-        fpc.move(to: .full, animated: true)
-    }
-
-    // MARK: FloatingPanelControllerDelegate
-    
-    func floatingPanel(_ vc: FloatingPanelController, layoutFor newCollection: UITraitCollection) -> FloatingPanelLayout? {
-        switch newCollection.verticalSizeClass {
-        case .compact:
-            fpc.surfaceView.borderWidth = 1.0 / traitCollection.displayScale
-            fpc.surfaceView.borderColor = UIColor.black.withAlphaComponent(0.2)
-            return SearchPanelLandscapeLayout()
-        default:
-            fpc.surfaceView.borderWidth = 0.0
-            fpc.surfaceView.borderColor = nil
-            return nil
-        }
-    }
-
-    func floatingPanelDidMove(_ vc: FloatingPanelController) {
-        let y = vc.surfaceView.frame.origin.y
-        let tipY = vc.originYOfSurface(for: .tip)
-        if y > tipY - 44.0 {
-            let progress = max(0.0, min((tipY  - y) / 44.0, 1.0))
-            self.searchVC.tableView.alpha = progress
-        }
-    }
-
-    func floatingPanelWillBeginDragging(_ vc: FloatingPanelController) {
-        if vc.position == .full {
-            searchVC.searchBar.showsCancelButton = false
-            searchVC.searchBar.resignFirstResponder()
-        }
-    }
-
-    func floatingPanelDidEndDragging(_ vc: FloatingPanelController, withVelocity velocity: CGPoint, targetPosition: FloatingPanelPosition) {
-        if targetPosition != .full {
-            searchVC.hideHeader()
-        }
-
-        UIView.animate(withDuration: 0.25,
-                       delay: 0.0,
-                       options: .allowUserInteraction,
-                       animations: {
-                        if targetPosition == .tip {
-                            self.searchVC.tableView.alpha = 0.0
-                        } else {
-                            self.searchVC.tableView.alpha = 1.0
-                        }
-        }, completion: nil)
-    }
-}
-
-class SearchPanelViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {
-
-    @IBOutlet weak var tableView: UITableView!
-    @IBOutlet weak var searchBar: UISearchBar!
-    @IBOutlet weak var visualEffectView: UIVisualEffectView!
-    
-    override func viewDidLoad() {
-        super.viewDidLoad()
-        tableView.dataSource = self
-        tableView.delegate = self
-        searchBar.placeholder = "Search for a place or address"
-        let textField = searchBar.value(forKey: "_searchField") as! UITextField
-        textField.font = UIFont(name: textField.font!.fontName, size: 15.0)
-
-        hideHeader()
-
-    }
-
-    override func viewDidLayoutSubviews() {
-        super.viewDidLayoutSubviews()
-        if #available(iOS 10, *) {
-            visualEffectView.layer.cornerRadius = 9.0
-            visualEffectView.clipsToBounds = true
-        }
-    }
-
-    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
-        return 2
-    }
-
-    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
-        let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath)
-        if let cell = cell as? SearchCell {
-            switch indexPath.row {
-            case 0:
-                cell.iconImageView.image = UIImage(named: "mark")
-                cell.titleLabel.text = "Marked Location"
-                cell.subTitleLabel.text = "Golden Gate Bridge, San Francisco"
-            case 1:
-                cell.iconImageView.image = UIImage(named: "like")
-                cell.titleLabel.text = "Favorites"
-                cell.subTitleLabel.text = "0 Places"
-            default:
-                break
-            }
-        }
-        return cell
-    }
-
-    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
-        tableView.deselectRow(at: indexPath, animated: false)
-    }
-
-    func showHeader() {
-        changeHeader(height: 116.0)
-    }
-
-    func hideHeader() {
-        changeHeader(height: 0.0)
-    }
-
-    func changeHeader(height: CGFloat) {
-        tableView.beginUpdates()
-        if let headerView = tableView.tableHeaderView  {
-            UIView.animate(withDuration: 0.25) {
-                var frame = headerView.frame
-                frame.size.height = height
-                self.tableView.tableHeaderView?.frame = frame
-            }
-        }
-        tableView.endUpdates()
-    }
-}
-
-public class SearchPanelLandscapeLayout: FloatingPanelLayout {
-    public var initialPosition: FloatingPanelPosition {
-        return .tip
-    }
-    
-    public var supportedPositions: Set<FloatingPanelPosition> {
-        return [.full, .tip]
-    }
-
-    public func insetFor(position: FloatingPanelPosition) -> CGFloat? {
-        switch position {
-        case .full: return 16.0
-        case .tip: return 69.0
-        default: return nil
-        }
-    }
-
-    public func prepareLayout(surfaceView: UIView, in view: UIView) -> [NSLayoutConstraint] {
-        if #available(iOS 11.0, *) {
-            return [
-                surfaceView.leftAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leftAnchor, constant: 8.0),
-                surfaceView.widthAnchor.constraint(equalToConstant: 291),
-            ]
-        } else {
-            return [
-                surfaceView.leftAnchor.constraint(equalTo: view.leftAnchor, constant: 8.0),
-                surfaceView.widthAnchor.constraint(equalToConstant: 291),
-            ]
-        }
-    }
-
-    public func backdropAlphaFor(position: FloatingPanelPosition) -> CGFloat {
-        return 0.0
-    }
-}
-
-class SearchCell: UITableViewCell {
-    @IBOutlet weak var iconImageView: UIImageView!
-    @IBOutlet weak var titleLabel: UILabel!
-    @IBOutlet weak var subTitleLabel: UILabel!
-}
-
-class SearchHeaderView: UIView {
-    required init?(coder aDecoder: NSCoder) {
-        super.init(coder: aDecoder)
-        self.clipsToBounds = true
-    }
 }

Examples/Samples/Samples.xcodeproj/project.pbxproj

@@ -14,9 +14,11 @@
 		545DB9F821511E6400CA77B8 /* LaunchScreen.storyboard in Resources */ = {isa = PBXBuildFile; fileRef = 545DB9F621511E6400CA77B8 /* LaunchScreen.storyboard */; };
 		545DBA0321511E6400CA77B8 /* SampleTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 545DBA0221511E6400CA77B8 /* SampleTests.swift */; };
 		545DBA0E21511E6400CA77B8 /* SampleUITests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 545DBA0D21511E6400CA77B8 /* SampleUITests.swift */; };
-		54B51116216AFE5F0033A6F3 /* UIExtensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54B51115216AFE5F0033A6F3 /* UIExtensions.swift */; };
-		54B5113C216C40670033A6F3 /* FloatingPanel.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 54B5113B216C40670033A6F3 /* FloatingPanel.framework */; };
-		54B5113D216C40670033A6F3 /* FloatingPanel.framework in Embed Frameworks */ = {isa = PBXBuildFile; fileRef = 54B5113B216C40670033A6F3 /* FloatingPanel.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
+		546341A125C6415100CA0596 /* UseCases.swift in Sources */ = {isa = PBXBuildFile; fileRef = 546341A025C6415100CA0596 /* UseCases.swift */; };
+		546341AC25C6426500CA0596 /* CustomState.swift in Sources */ = {isa = PBXBuildFile; fileRef = 546341AB25C6426500CA0596 /* CustomState.swift */; };
+		549D23CB233C7779008EF4D7 /* FloatingPanel.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 549D23CA233C7779008EF4D7 /* FloatingPanel.framework */; };
+		549D23CC233C7779008EF4D7 /* FloatingPanel.framework in Embed Frameworks */ = {isa = PBXBuildFile; fileRef = 549D23CA233C7779008EF4D7 /* FloatingPanel.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
+		54B51116216AFE5F0033A6F3 /* Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54B51115216AFE5F0033A6F3 /* Extensions.swift */; };
 		54CDC5D8215BBE23007D205C /* UIComponents.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54CDC5D7215BBE23007D205C /* UIComponents.swift */; };
 /* End PBXBuildFile section */
 
@@ -38,13 +40,13 @@
 /* End PBXContainerItemProxy section */
 
 /* Begin PBXCopyFilesBuildPhase section */
-		54B5111C216C3B300033A6F3 /* Embed Frameworks */ = {
+		549D23CD233C7779008EF4D7 /* Embed Frameworks */ = {
 			isa = PBXCopyFilesBuildPhase;
 			buildActionMask = 2147483647;
 			dstPath = "";
 			dstSubfolderSpec = 10;
 			files = (
-				54B5113D216C40670033A6F3 /* FloatingPanel.framework in Embed Frameworks */,
+				549D23CC233C7779008EF4D7 /* FloatingPanel.framework in Embed Frameworks */,
 			);
 			name = "Embed Frameworks";
 			runOnlyForDeploymentPostprocessing = 0;
@@ -65,8 +67,10 @@
 		545DBA0921511E6400CA77B8 /* SamplesUITests.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = SamplesUITests.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
 		545DBA0D21511E6400CA77B8 /* SampleUITests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SampleUITests.swift; sourceTree = "<group>"; };
 		545DBA0F21511E6400CA77B8 /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
-		54B51115216AFE5F0033A6F3 /* UIExtensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = UIExtensions.swift; sourceTree = "<group>"; };
-		54B5113B216C40670033A6F3 /* FloatingPanel.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; path = FloatingPanel.framework; sourceTree = BUILT_PRODUCTS_DIR; };
+		546341A025C6415100CA0596 /* UseCases.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = UseCases.swift; sourceTree = "<group>"; };
+		546341AB25C6426500CA0596 /* CustomState.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CustomState.swift; sourceTree = "<group>"; };
+		549D23CA233C7779008EF4D7 /* FloatingPanel.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; path = FloatingPanel.framework; sourceTree = BUILT_PRODUCTS_DIR; };
+		54B51115216AFE5F0033A6F3 /* Extensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Extensions.swift; sourceTree = "<group>"; };
 		54CDC5D7215BBE23007D205C /* UIComponents.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = UIComponents.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
@@ -75,7 +79,7 @@
 			isa = PBXFrameworksBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
-				54B5113C216C40670033A6F3 /* FloatingPanel.framework in Frameworks */,
+				549D23CB233C7779008EF4D7 /* FloatingPanel.framework in Frameworks */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -99,12 +103,11 @@
 		545DB9E121511E6300CA77B8 = {
 			isa = PBXGroup;
 			children = (
-				54B5113B216C40670033A6F3 /* FloatingPanel.framework */,
+				549D23CA233C7779008EF4D7 /* FloatingPanel.framework */,
 				545DB9EC21511E6300CA77B8 /* Sources */,
 				545DBA0121511E6400CA77B8 /* Tests */,
 				545DBA0C21511E6400CA77B8 /* UITests */,
 				545DB9EB21511E6300CA77B8 /* Products */,
-				545DBA1B2151CC1000CA77B8 /* Frameworks */,
 			);
 			sourceTree = "<group>";
 		};
@@ -126,8 +129,9 @@
 				545DB9F121511E6300CA77B8 /* Main.storyboard */,
 				545DB9ED21511E6300CA77B8 /* AppDelegate.swift */,
 				545DB9EF21511E6300CA77B8 /* ViewController.swift */,
-				54B51115216AFE5F0033A6F3 /* UIExtensions.swift */,
+				54B51115216AFE5F0033A6F3 /* Extensions.swift */,
 				54CDC5D7215BBE23007D205C /* UIComponents.swift */,
+				546341AA25C6421000CA0596 /* UseCases */,
 				545DB9F921511E6400CA77B8 /* Info.plist */,
 			);
 			path = Sources;
@@ -151,11 +155,13 @@
 			path = UITests;
 			sourceTree = "<group>";
 		};
-		545DBA1B2151CC1000CA77B8 /* Frameworks */ = {
+		546341AA25C6421000CA0596 /* UseCases */ = {
 			isa = PBXGroup;
 			children = (
+				546341A025C6415100CA0596 /* UseCases.swift */,
+				546341AB25C6426500CA0596 /* CustomState.swift */,
 			);
-			name = Frameworks;
+			path = UseCases;
 			sourceTree = "<group>";
 		};
 /* End PBXGroup section */
@@ -169,7 +175,7 @@
 				545DB9E621511E6300CA77B8 /* Sources */,
 				545DB9E721511E6300CA77B8 /* Frameworks */,
 				545DB9E821511E6300CA77B8 /* Resources */,
-				54B5111C216C3B300033A6F3 /* Embed Frameworks */,
+				549D23CD233C7779008EF4D7 /* Embed Frameworks */,
 			);
 			buildRules = (
 			);
@@ -302,7 +308,7 @@
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 			shellPath = /bin/sh;
-			shellScript = "/usr/libexec/PlistBuddy -c \"Set :CFBundleVersion $(git rev-parse --abbrev-ref HEAD)($(git rev-parse --short HEAD))\" $SRCROOT/$INFOPLIST_FILE\n";
+			shellScript = "/usr/libexec/PlistBuddy -c \"Set :CFBundleVersion $(git rev-parse --abbrev-ref HEAD)($(git rev-parse --short HEAD))\" \"$SRCROOT/$INFOPLIST_FILE\"\n";
 		};
 /* End PBXShellScriptBuildPhase section */
 
@@ -312,7 +318,9 @@
 			buildActionMask = 2147483647;
 			files = (
 				54CDC5D8215BBE23007D205C /* UIComponents.swift in Sources */,
-				54B51116216AFE5F0033A6F3 /* UIExtensions.swift in Sources */,
+				54B51116216AFE5F0033A6F3 /* Extensions.swift in Sources */,
+				546341AC25C6426500CA0596 /* CustomState.swift in Sources */,
+				546341A125C6415100CA0596 /* UseCases.swift in Sources */,
 				545DB9F021511E6300CA77B8 /* ViewController.swift in Sources */,
 				545DB9EE21511E6300CA77B8 /* AppDelegate.swift in Sources */,
 			);
@@ -499,7 +507,7 @@
 				);
 				PRODUCT_BUNDLE_IDENTIFIER = com.scenee.FloatingPanelSample;
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 4.2;
+				SWIFT_VERSION = 5.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 			};
 			name = Debug;
@@ -518,7 +526,7 @@
 				);
 				PRODUCT_BUNDLE_IDENTIFIER = com.scenee.FloatingPanelSample;
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 4.2;
+				SWIFT_VERSION = 5.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 			};
 			name = Release;

Examples/Samples/Sources/AppDelegate.swift

@@ -1,7 +1,4 @@
-//
-//  Created by Shin Yamamoto on 2018/09/18.
-//  Copyright © 2018 Shin Yamamoto. All rights reserved.
-//
+// Copyright 2018 the FloatingPanel authors. All rights reserved. MIT license.
 
 import UIKit
 

Examples/Samples/Sources/Assets.xcassets/Contents.json

@@ -1,6 +1,6 @@
 {
   "info" : {
-    "version" : 1,
-    "author" : "xcode"
+    "author" : "xcode",
+    "version" : 1
   }
-}
+}

Examples/Samples/Sources/Assets.xcassets/IMG_0003.imageset/Contents.json

@@ -0,0 +1,12 @@
+{
+  "images" : [
+    {
+      "filename" : "IMG_0003.jpg",
+      "idiom" : "universal"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

Examples/Samples/Sources/Base.lproj/Main.storyboard

@@ -1,19 +1,19 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="14460.31" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" useSafeAreas="YES" colorMatched="YES" initialViewController="RoN-h0-uBD">
-    <device id="retina5_9" orientation="portrait">
-        <adaptation id="fullscreen"/>
-    </device>
+<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="17506" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" useSafeAreas="YES" colorMatched="YES" initialViewController="RoN-h0-uBD">
+    <device id="retina5_9" orientation="portrait" appearance="light"/>
     <dependencies>
         <deployment identifier="iOS"/>
-        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="14460.20"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="17505"/>
         <capability name="Safe area layout guides" minToolsVersion="9.0"/>
+        <capability name="Stack View standard spacing" minToolsVersion="9.0"/>
+        <capability name="System colors in document resources" minToolsVersion="11.0"/>
         <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
     </dependencies>
     <scenes>
         <!--Navigation Controller-->
         <scene sceneID="Cjh-iX-VQw">
             <objects>
-                <navigationController id="RoN-h0-uBD" sceneMemberID="viewController">
+                <navigationController storyboardIdentifier="RootNavigationController" id="RoN-h0-uBD" sceneMemberID="viewController">
                     <navigationBar key="navigationBar" contentMode="scaleToFill" insetsLayoutMarginsFromSafeArea="NO" largeTitles="YES" id="hNW-5m-Omi">
                         <rect key="frame" x="0.0" y="44" width="375" height="96"/>
                         <autoresizingMask key="autoresizingMask"/>
@@ -35,18 +35,18 @@
                         <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                         <subviews>
                             <tableView clipsSubviews="YES" contentMode="scaleToFill" alwaysBounceVertical="YES" dataMode="prototypes" style="plain" separatorStyle="default" rowHeight="-1" estimatedRowHeight="-1" sectionHeaderHeight="28" sectionFooterHeight="28" translatesAutoresizingMaskIntoConstraints="NO" id="7IS-PU-x0P">
-                                <rect key="frame" x="0.0" y="0.0" width="375" height="778"/>
+                                <rect key="frame" x="0.0" y="0.0" width="375" height="812"/>
                                 <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
                                 <prototypes>
                                     <tableViewCell clipsSubviews="YES" contentMode="scaleToFill" preservesSuperviewLayoutMargins="YES" selectionStyle="default" indentationWidth="10" reuseIdentifier="Cell" textLabel="M0G-C8-hAO" style="IBUITableViewCellStyleDefault" id="ySY-oA-g81">
-                                        <rect key="frame" x="0.0" y="28" width="375" height="44"/>
+                                        <rect key="frame" x="0.0" y="28" width="375" height="43.666667938232422"/>
                                         <autoresizingMask key="autoresizingMask"/>
                                         <tableViewCellContentView key="contentView" opaque="NO" clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="center" preservesSuperviewLayoutMargins="YES" insetsLayoutMarginsFromSafeArea="NO" tableViewCell="ySY-oA-g81" id="sXB-nH-2g2">
-                                            <rect key="frame" x="0.0" y="0.0" width="375" height="43.666666666666664"/>
+                                            <rect key="frame" x="0.0" y="0.0" width="375" height="43.666667938232422"/>
                                             <autoresizingMask key="autoresizingMask"/>
                                             <subviews>
                                                 <label opaque="NO" multipleTouchEnabled="YES" contentMode="left" insetsLayoutMarginsFromSafeArea="NO" text="Title" textAlignment="natural" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" id="M0G-C8-hAO">
-                                                    <rect key="frame" x="15" y="0.0" width="345" height="43.666666666666664"/>
+                                                    <rect key="frame" x="16" y="0.0" width="343" height="43.666667938232422"/>
                                                     <autoresizingMask key="autoresizingMask"/>
                                                     <fontDescription key="fontDescription" type="system" pointSize="17"/>
                                                     <nil key="textColor"/>
@@ -58,14 +58,14 @@
                                 </prototypes>
                             </tableView>
                         </subviews>
+                        <viewLayoutGuide key="safeArea" id="39L-Nq-qfp"/>
                         <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
                         <constraints>
                             <constraint firstItem="7IS-PU-x0P" firstAttribute="top" secondItem="Smh-Bd-AAc" secondAttribute="top" id="6yd-jv-ey3"/>
                             <constraint firstItem="7IS-PU-x0P" firstAttribute="leading" secondItem="39L-Nq-qfp" secondAttribute="leading" id="Z6Y-Dc-cei"/>
-                            <constraint firstItem="7IS-PU-x0P" firstAttribute="bottom" secondItem="39L-Nq-qfp" secondAttribute="bottom" id="fNW-DP-lhV"/>
+                            <constraint firstItem="7IS-PU-x0P" firstAttribute="bottom" secondItem="Smh-Bd-AAc" secondAttribute="bottom" id="fNW-DP-lhV"/>
                             <constraint firstItem="7IS-PU-x0P" firstAttribute="trailing" secondItem="39L-Nq-qfp" secondAttribute="trailing" id="vfY-Rc-FOI"/>
                         </constraints>
-                        <viewLayoutGuide key="safeArea" id="39L-Nq-qfp"/>
                     </view>
                     <navigationItem key="navigationItem" title="Samples" id="wCF-su-7up">
                         <barButtonItem key="rightBarButtonItem" title="Settings" id="rbH-U3-XyA">
@@ -87,69 +87,79 @@
             <objects>
                 <viewController storyboardIdentifier="SettingsViewController" id="C1X-9Z-TyQ" customClass="SettingsViewController" customModule="Samples" customModuleProvider="target" sceneMemberID="viewController">
                     <view key="view" contentMode="scaleToFill" insetsLayoutMarginsFromSafeArea="NO" id="af9-Zr-Ppc">
-                        <rect key="frame" x="0.0" y="0.0" width="375" height="197.33000000000001"/>
+                        <rect key="frame" x="0.0" y="0.0" width="375" height="197.33333333333334"/>
                         <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                         <subviews>
-                            <stackView opaque="NO" contentMode="scaleToFill" axis="vertical" distribution="fillProportionally" alignment="center" spacing="16" translatesAutoresizingMaskIntoConstraints="NO" id="n93-ZL-fmC">
-                                <rect key="frame" x="32" y="16" width="311" height="147.33333333333334"/>
+                            <stackView opaque="NO" contentMode="scaleToFill" axis="vertical" distribution="fillProportionally" spacing="16" translatesAutoresizingMaskIntoConstraints="NO" id="n93-ZL-fmC">
+                                <rect key="frame" x="32" y="16" width="311" height="149.33333333333334"/>
                                 <subviews>
-                                    <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Version: 1.0" textAlignment="natural" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="WmC-Tq-NDN">
-                                        <rect key="frame" x="118.33333333333334" y="0.0" width="74.333333333333343" height="17"/>
-                                        <fontDescription key="fontDescription" type="system" pointSize="14"/>
-                                        <nil key="textColor"/>
-                                        <nil key="highlightedColor"/>
-                                    </label>
-                                    <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="UINavigationBar" textAlignment="natural" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="Ulg-gS-ah0">
-                                        <rect key="frame" x="90.666666666666686" y="33" width="130" height="20.333333333333329"/>
-                                        <fontDescription key="fontDescription" style="UICTFontTextStyleHeadline"/>
-                                        <nil key="textColor"/>
-                                        <nil key="highlightedColor"/>
-                                    </label>
-                                    <stackView opaque="NO" contentMode="scaleToFill" alignment="center" spacing="126" translatesAutoresizingMaskIntoConstraints="NO" id="uEf-g4-CeU">
-                                        <rect key="frame" x="23.333333333333343" y="69.333333333333329" width="264.33333333333326" height="31"/>
+                                    <stackView opaque="NO" contentMode="scaleToFill" axis="vertical" distribution="fillProportionally" alignment="center" spacing="8" translatesAutoresizingMaskIntoConstraints="NO" id="DCi-Iv-o6d">
+                                        <rect key="frame" x="0.0" y="0.0" width="311" height="52.666666666666664"/>
                                         <subviews>
-                                            <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Large Titles" textAlignment="natural" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="ogl-S5-4tJ">
-                                                <rect key="frame" x="0.0" y="5.3333333333333428" width="89.333333333333329" height="20.333333333333332"/>
-                                                <fontDescription key="fontDescription" type="system" pointSize="17"/>
+                                            <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Version: 1.0" textAlignment="natural" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="WmC-Tq-NDN">
+                                                <rect key="frame" x="118.33333333333334" y="0.0" width="74.333333333333343" height="17.333333333333332"/>
+                                                <fontDescription key="fontDescription" type="system" pointSize="14"/>
+                                                <nil key="textColor"/>
+                                                <nil key="highlightedColor"/>
+                                            </label>
+                                            <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="UINavigationBar" textAlignment="natural" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="Ulg-gS-ah0">
+                                                <rect key="frame" x="78.333333333333329" y="25.333333333333336" width="154.66666666666669" height="27.333333333333336"/>
+                                                <fontDescription key="fontDescription" style="UICTFontTextStyleTitle2"/>
                                                 <nil key="textColor"/>
                                                 <nil key="highlightedColor"/>
                                             </label>
-                                            <switch opaque="NO" contentMode="scaleToFill" horizontalHuggingPriority="750" verticalHuggingPriority="750" contentHorizontalAlignment="center" contentVerticalAlignment="center" translatesAutoresizingMaskIntoConstraints="NO" id="js8-Qv-lUC">
-                                                <rect key="frame" x="215.33333333333334" y="0.0" width="51.000000000000028" height="31"/>
-                                                <connections>
-                                                    <action selector="toggleLargeTitle:" destination="C1X-9Z-TyQ" eventType="valueChanged" id="FJS-Ty-mCY"/>
-                                                </connections>
-                                            </switch>
                                         </subviews>
                                     </stackView>
-                                    <stackView opaque="NO" contentMode="scaleToFill" spacing="126" translatesAutoresizingMaskIntoConstraints="NO" id="ZtZ-Dz-4cC">
-                                        <rect key="frame" x="23.333333333333343" y="116.33333333333334" width="264.66666666666663" height="31"/>
+                                    <stackView opaque="NO" contentMode="scaleToFill" axis="vertical" distribution="fillProportionally" spacing="16" translatesAutoresizingMaskIntoConstraints="NO" id="J8j-7w-yCZ">
+                                        <rect key="frame" x="0.0" y="68.666666666666657" width="311" height="80.666666666666657"/>
                                         <subviews>
-                                            <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Translucent" textAlignment="natural" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="Z5i-rm-QgL">
-                                                <rect key="frame" x="0.0" y="0.0" width="89.666666666666671" height="31"/>
-                                                <fontDescription key="fontDescription" type="system" pointSize="17"/>
-                                                <nil key="textColor"/>
-                                                <nil key="highlightedColor"/>
-                                            </label>
-                                            <switch opaque="NO" contentMode="scaleToFill" horizontalHuggingPriority="750" verticalHuggingPriority="750" contentHorizontalAlignment="center" contentVerticalAlignment="center" translatesAutoresizingMaskIntoConstraints="NO" id="s6b-j9-8Kw">
-                                                <rect key="frame" x="215.66666666666666" y="0.0" width="50.999999999999972" height="31"/>
-                                                <connections>
-                                                    <action selector="toggleTranslucent:" destination="C1X-9Z-TyQ" eventType="valueChanged" id="nL4-3L-9hh"/>
-                                                </connections>
-                                            </switch>
+                                            <stackView opaque="NO" contentMode="scaleToFill" alignment="center" spacingType="standard" translatesAutoresizingMaskIntoConstraints="NO" id="uEf-g4-CeU">
+                                                <rect key="frame" x="0.0" y="0.0" width="311" height="32"/>
+                                                <subviews>
+                                                    <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Large Titles" textAlignment="natural" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="ogl-S5-4tJ">
+                                                        <rect key="frame" x="0.0" y="5.9999999999999982" width="254" height="20.333333333333329"/>
+                                                        <fontDescription key="fontDescription" style="UICTFontTextStyleHeadline"/>
+                                                        <nil key="textColor"/>
+                                                        <nil key="highlightedColor"/>
+                                                    </label>
+                                                    <switch opaque="NO" contentMode="scaleToFill" horizontalHuggingPriority="750" verticalHuggingPriority="750" contentHorizontalAlignment="center" contentVerticalAlignment="center" translatesAutoresizingMaskIntoConstraints="NO" id="js8-Qv-lUC">
+                                                        <rect key="frame" x="262" y="0.66666666666665719" width="51" height="31"/>
+                                                        <connections>
+                                                            <action selector="toggleLargeTitle:" destination="C1X-9Z-TyQ" eventType="valueChanged" id="FJS-Ty-mCY"/>
+                                                        </connections>
+                                                    </switch>
+                                                </subviews>
+                                            </stackView>
+                                            <stackView opaque="NO" contentMode="scaleToFill" alignment="center" spacingType="standard" translatesAutoresizingMaskIntoConstraints="NO" id="ZtZ-Dz-4cC">
+                                                <rect key="frame" x="0.0" y="47.999999999999986" width="311" height="32.666666666666671"/>
+                                                <subviews>
+                                                    <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Translucent" textAlignment="natural" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="Z5i-rm-QgL">
+                                                        <rect key="frame" x="0.0" y="6.333333333333341" width="254" height="20.333333333333329"/>
+                                                        <fontDescription key="fontDescription" style="UICTFontTextStyleHeadline"/>
+                                                        <nil key="textColor"/>
+                                                        <nil key="highlightedColor"/>
+                                                    </label>
+                                                    <switch opaque="NO" contentMode="scaleToFill" horizontalHuggingPriority="750" verticalHuggingPriority="750" contentHorizontalAlignment="center" contentVerticalAlignment="center" translatesAutoresizingMaskIntoConstraints="NO" id="s6b-j9-8Kw">
+                                                        <rect key="frame" x="262" y="1" width="51" height="31"/>
+                                                        <connections>
+                                                            <action selector="toggleTranslucent:" destination="C1X-9Z-TyQ" eventType="valueChanged" id="nL4-3L-9hh"/>
+                                                        </connections>
+                                                    </switch>
+                                                </subviews>
+                                            </stackView>
                                         </subviews>
                                     </stackView>
                                 </subviews>
                             </stackView>
                         </subviews>
+                        <viewLayoutGuide key="safeArea" id="0hr-ty-yWm"/>
                         <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
                         <constraints>
-                            <constraint firstItem="0hr-ty-yWm" firstAttribute="bottom" secondItem="n93-ZL-fmC" secondAttribute="bottom" id="2Ey-ou-E1M"/>
+                            <constraint firstAttribute="bottom" secondItem="n93-ZL-fmC" secondAttribute="bottom" constant="32" id="2Ey-ou-E1M"/>
                             <constraint firstAttribute="trailing" secondItem="n93-ZL-fmC" secondAttribute="trailing" constant="32" id="DdZ-eB-F5s"/>
                             <constraint firstItem="n93-ZL-fmC" firstAttribute="leading" secondItem="af9-Zr-Ppc" secondAttribute="leading" constant="32" id="TyK-GP-Ari"/>
                             <constraint firstItem="n93-ZL-fmC" firstAttribute="top" secondItem="af9-Zr-Ppc" secondAttribute="topMargin" constant="16" id="mbC-6H-z9M"/>
                         </constraints>
-                        <viewLayoutGuide key="safeArea" id="0hr-ty-yWm"/>
                     </view>
                     <size key="freeformSize" width="375" height="197.33000000000001"/>
                     <connections>
@@ -162,7 +172,7 @@
             </objects>
             <point key="canvasLocation" x="708" y="-200"/>
         </scene>
-        <!--Item 2-->
+        <!--Layout 2-->
         <scene sceneID="lRc-OZ-sL4">
             <objects>
                 <viewController id="RpE-lI-27a" customClass="TabBarContentViewController" customModule="Samples" customModuleProvider="target" sceneMemberID="viewController">
@@ -170,13 +180,7 @@
                         <rect key="frame" x="0.0" y="0.0" width="375" height="812"/>
                         <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                         <subviews>
-                            <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Item 2" textAlignment="natural" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="AiP-dx-mFn">
-                                <rect key="frame" x="163.66666666666666" y="395.66666666666669" width="48" height="21"/>
-                                <fontDescription key="fontDescription" type="system" pointSize="17"/>
-                                <nil key="textColor"/>
-                                <nil key="highlightedColor"/>
-                            </label>
-                            <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="roundedRect" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="IvG-yp-yzI">
+                            <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="system" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="IvG-yp-yzI">
                                 <rect key="frame" x="20" y="44" width="39" height="30"/>
                                 <state key="normal" title="Close"/>
                                 <connections>
@@ -185,22 +189,52 @@
                                 </connections>
                             </button>
                         </subviews>
+                        <viewLayoutGuide key="safeArea" id="954-Dk-zvc"/>
                         <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
                         <constraints>
                             <constraint firstItem="IvG-yp-yzI" firstAttribute="top" secondItem="954-Dk-zvc" secondAttribute="top" id="18k-sV-PgT"/>
-                            <constraint firstItem="AiP-dx-mFn" firstAttribute="centerY" secondItem="JER-jz-KSq" secondAttribute="centerY" id="NUc-tM-0dN"/>
-                            <constraint firstItem="AiP-dx-mFn" firstAttribute="centerX" secondItem="954-Dk-zvc" secondAttribute="centerX" id="hwP-mu-Vmz"/>
+                            <constraint firstItem="954-Dk-zvc" firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="IvG-yp-yzI" secondAttribute="trailing" id="mpr-u5-MZu"/>
                             <constraint firstItem="IvG-yp-yzI" firstAttribute="leading" secondItem="954-Dk-zvc" secondAttribute="leading" constant="20" id="pYt-jE-CTF"/>
                         </constraints>
-                        <viewLayoutGuide key="safeArea" id="954-Dk-zvc"/>
                     </view>
-                    <tabBarItem key="tabBarItem" tag="1" title="Item 2" id="qb3-RB-B28"/>
+                    <tabBarItem key="tabBarItem" tag="1" title="Layout 2" id="qb3-RB-B28"/>
                 </viewController>
                 <placeholder placeholderIdentifier="IBFirstResponder" id="NhZ-u5-Beh" userLabel="First Responder" sceneMemberID="firstResponder"/>
             </objects>
             <point key="canvasLocation" x="-308" y="1546"/>
         </scene>
-        <!--Item 1-->
+        <!--Layout 3-->
+        <scene sceneID="r9h-Ql-gIv">
+            <objects>
+                <viewController id="pOk-Zm-vD9" customClass="TabBarContentViewController" customModule="Samples" customModuleProvider="target" sceneMemberID="viewController">
+                    <view key="view" contentMode="scaleToFill" id="85d-ub-G8k">
+                        <rect key="frame" x="0.0" y="0.0" width="375" height="812"/>
+                        <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
+                        <subviews>
+                            <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="system" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="NbG-e8-HdI">
+                                <rect key="frame" x="20" y="44" width="39" height="30"/>
+                                <state key="normal" title="Close"/>
+                                <connections>
+                                    <action selector="closeWithSender:" destination="pOk-Zm-vD9" eventType="touchUpInside" id="111-PD-Pop"/>
+                                    <action selector="closeWithSender:" destination="bYI-y3-Rzb" eventType="touchUpInside" id="1Rg-YG-TtU"/>
+                                </connections>
+                            </button>
+                        </subviews>
+                        <viewLayoutGuide key="safeArea" id="0ao-SI-QZW"/>
+                        <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
+                        <constraints>
+                            <constraint firstItem="0ao-SI-QZW" firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="NbG-e8-HdI" secondAttribute="trailing" id="K9F-6x-KWn"/>
+                            <constraint firstItem="NbG-e8-HdI" firstAttribute="top" secondItem="0ao-SI-QZW" secondAttribute="top" id="nsE-so-rTl"/>
+                            <constraint firstItem="NbG-e8-HdI" firstAttribute="leading" secondItem="0ao-SI-QZW" secondAttribute="leading" constant="20" id="sF4-Dm-aoY"/>
+                        </constraints>
+                    </view>
+                    <tabBarItem key="tabBarItem" tag="2" title="Layout 3" id="RJD-TF-Sdh"/>
+                </viewController>
+                <placeholder placeholderIdentifier="IBFirstResponder" id="Oe3-FT-q1C" userLabel="First Responder" sceneMemberID="firstResponder"/>
+            </objects>
+            <point key="canvasLocation" x="332" y="1546"/>
+        </scene>
+        <!--Layout 1-->
         <scene sceneID="m6X-j6-yBM">
             <objects>
                 <viewController id="lto-Zc-Vtp" customClass="TabBarContentViewController" customModule="Samples" customModuleProvider="target" sceneMemberID="viewController">
@@ -208,13 +242,7 @@
                         <rect key="frame" x="0.0" y="0.0" width="375" height="812"/>
                         <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                         <subviews>
-                            <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Item 1" textAlignment="natural" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="uoW-c8-9wx">
-                                <rect key="frame" x="164.66666666666666" y="395.66666666666669" width="46" height="21"/>
-                                <fontDescription key="fontDescription" type="system" pointSize="17"/>
-                                <nil key="textColor"/>
-                                <nil key="highlightedColor"/>
-                            </label>
-                            <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="roundedRect" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="eFN-tN-4Ct">
+                            <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="system" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="eFN-tN-4Ct">
                                 <rect key="frame" x="20" y="44" width="39" height="30"/>
                                 <state key="normal" title="Close"/>
                                 <connections>
@@ -223,16 +251,15 @@
                                 </connections>
                             </button>
                         </subviews>
+                        <viewLayoutGuide key="safeArea" id="5Ns-4l-Ufg"/>
                         <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
                         <constraints>
                             <constraint firstItem="eFN-tN-4Ct" firstAttribute="leading" secondItem="5Ns-4l-Ufg" secondAttribute="leading" constant="20" id="5BT-yZ-EKe"/>
-                            <constraint firstItem="uoW-c8-9wx" firstAttribute="centerY" secondItem="ji9-Ez-N7i" secondAttribute="centerY" id="Nyw-Wt-78z"/>
+                            <constraint firstItem="5Ns-4l-Ufg" firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="eFN-tN-4Ct" secondAttribute="trailing" id="OzZ-Dz-RNF"/>
                             <constraint firstItem="eFN-tN-4Ct" firstAttribute="top" secondItem="5Ns-4l-Ufg" secondAttribute="top" id="hUV-3a-XkY"/>
-                            <constraint firstItem="uoW-c8-9wx" firstAttribute="centerX" secondItem="5Ns-4l-Ufg" secondAttribute="centerX" id="wDv-OH-7PX"/>
                         </constraints>
-                        <viewLayoutGuide key="safeArea" id="5Ns-4l-Ufg"/>
                     </view>
-                    <tabBarItem key="tabBarItem" title="Item 1" id="HEV-kf-jxH"/>
+                    <tabBarItem key="tabBarItem" title="Layout 1" id="HEV-kf-jxH"/>
                 </viewController>
                 <placeholder placeholderIdentifier="IBFirstResponder" id="bkL-bc-hZC" userLabel="First Responder" sceneMemberID="firstResponder"/>
             </objects>
@@ -247,20 +274,19 @@
                         <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                         <subviews>
                             <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="1000" verticalHuggingPriority="1000" horizontalCompressionResistancePriority="1000" verticalCompressionResistancePriority="1000" text="Change this text" textAlignment="center" lineBreakMode="tailTruncation" numberOfLines="0" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="ge4-RW-Gmz">
-                                <rect key="frame" x="24" y="24" width="327" height="20.333333333333329"/>
+                                <rect key="frame" x="125.66666666666669" y="24" width="124" height="20.333333333333329"/>
                                 <fontDescription key="fontDescription" type="system" pointSize="17"/>
                                 <nil key="textColor"/>
                                 <nil key="highlightedColor"/>
                             </label>
                         </subviews>
+                        <viewLayoutGuide key="safeArea" id="ouu-g9-OiX"/>
                         <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
                         <constraints>
-                            <constraint firstAttribute="trailing" secondItem="ge4-RW-Gmz" secondAttribute="trailing" constant="24" id="V59-MD-Lcg"/>
-                            <constraint firstItem="ge4-RW-Gmz" firstAttribute="leading" secondItem="eLM-xc-d9e" secondAttribute="leading" constant="24" id="hAO-P0-7Kw"/>
                             <constraint firstItem="ge4-RW-Gmz" firstAttribute="top" secondItem="eLM-xc-d9e" secondAttribute="top" constant="24" id="j0s-fd-MYj"/>
                             <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="ge4-RW-Gmz" secondAttribute="bottom" constant="24" id="tEn-PO-nVD"/>
+                            <constraint firstItem="ge4-RW-Gmz" firstAttribute="centerX" secondItem="eLM-xc-d9e" secondAttribute="centerX" id="vh3-l7-uY8"/>
                         </constraints>
-                        <viewLayoutGuide key="safeArea" id="ouu-g9-OiX"/>
                     </view>
                     <size key="freeformSize" width="375" height="778"/>
                 </viewController>
@@ -268,6 +294,71 @@
             </objects>
             <point key="canvasLocation" x="2753" y="734"/>
         </scene>
+        <!--Image View Controller-->
+        <scene sceneID="NAI-Rh-ZQ6">
+            <objects>
+                <viewController storyboardIdentifier="ImageViewController" id="VWY-cF-RoY" customClass="ImageViewController" customModule="Samples" sceneMemberID="viewController">
+                    <view key="view" contentMode="scaleToFill" id="dAf-gD-ghB">
+                        <rect key="frame" x="0.0" y="0.0" width="375" height="778"/>
+                        <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
+                        <subviews>
+                            <stackView opaque="NO" contentMode="scaleToFill" axis="vertical" translatesAutoresizingMaskIntoConstraints="NO" id="Gs4-S6-Goh">
+                                <rect key="frame" x="0.0" y="0.0" width="375" height="778"/>
+                                <subviews>
+                                    <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="t7x-eG-MKh">
+                                        <rect key="frame" x="0.0" y="0.0" width="375" height="49"/>
+                                        <color key="backgroundColor" systemColor="systemOrangeColor"/>
+                                        <constraints>
+                                            <constraint firstAttribute="height" constant="49" id="DmG-pt-gij"/>
+                                        </constraints>
+                                    </view>
+                                    <scrollView clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="scaleToFill" alwaysBounceVertical="YES" alwaysBounceHorizontal="YES" showsHorizontalScrollIndicator="NO" showsVerticalScrollIndicator="NO" translatesAutoresizingMaskIntoConstraints="NO" id="kRA-qy-GpJ">
+                                        <rect key="frame" x="0.0" y="49" width="375" height="680"/>
+                                        <subviews>
+                                            <imageView clipsSubviews="YES" userInteractionEnabled="NO" contentMode="scaleAspectFill" horizontalHuggingPriority="1000" verticalHuggingPriority="1000" image="IMG_0003" translatesAutoresizingMaskIntoConstraints="NO" id="rGf-jW-WNf">
+                                                <rect key="frame" x="0.0" y="0.0" width="750" height="501"/>
+                                                <color key="backgroundColor" systemColor="systemPurpleColor"/>
+                                            </imageView>
+                                        </subviews>
+                                        <color key="backgroundColor" red="0.0078431372550000003" green="0.72156862749999995" blue="0.45882352939999999" alpha="1" colorSpace="calibratedRGB"/>
+                                        <constraints>
+                                            <constraint firstAttribute="trailing" secondItem="rGf-jW-WNf" secondAttribute="trailing" id="472-Be-cUl"/>
+                                            <constraint firstAttribute="bottom" secondItem="rGf-jW-WNf" secondAttribute="bottom" id="ncs-tN-3Wx"/>
+                                            <constraint firstItem="rGf-jW-WNf" firstAttribute="leading" secondItem="kRA-qy-GpJ" secondAttribute="leading" id="rlv-5Y-utR"/>
+                                            <constraint firstItem="rGf-jW-WNf" firstAttribute="top" secondItem="kRA-qy-GpJ" secondAttribute="top" id="zum-Zl-Wzz"/>
+                                        </constraints>
+                                    </scrollView>
+                                    <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="SEa-7Y-wa9">
+                                        <rect key="frame" x="0.0" y="729" width="375" height="49"/>
+                                        <color key="backgroundColor" systemColor="systemTealColor"/>
+                                        <constraints>
+                                            <constraint firstAttribute="height" constant="49" id="3mS-zi-8BP"/>
+                                        </constraints>
+                                    </view>
+                                </subviews>
+                            </stackView>
+                        </subviews>
+                        <viewLayoutGuide key="safeArea" id="hCg-v5-nJs"/>
+                        <color key="backgroundColor" systemColor="systemBackgroundColor"/>
+                        <constraints>
+                            <constraint firstAttribute="trailing" secondItem="Gs4-S6-Goh" secondAttribute="trailing" id="6z7-Md-pxr"/>
+                            <constraint firstAttribute="bottom" secondItem="Gs4-S6-Goh" secondAttribute="bottom" id="PcQ-bu-yT3"/>
+                            <constraint firstItem="Gs4-S6-Goh" firstAttribute="top" secondItem="dAf-gD-ghB" secondAttribute="top" id="zGx-Wd-hjz"/>
+                            <constraint firstItem="Gs4-S6-Goh" firstAttribute="leading" secondItem="dAf-gD-ghB" secondAttribute="leading" id="zxi-Ty-U7L"/>
+                        </constraints>
+                    </view>
+                    <size key="freeformSize" width="375" height="778"/>
+                    <connections>
+                        <outlet property="footerView" destination="SEa-7Y-wa9" id="Gzj-dP-YXl"/>
+                        <outlet property="headerView" destination="t7x-eG-MKh" id="njM-un-U8q"/>
+                        <outlet property="scrollView" destination="kRA-qy-GpJ" id="iWC-o4-APi"/>
+                        <outlet property="stackView" destination="Gs4-S6-Goh" id="f1D-bO-mjr"/>
+                    </connections>
+                </viewController>
+                <placeholder placeholderIdentifier="IBFirstResponder" id="pnR-69-Ek4" userLabel="First Responder" customClass="UIResponder" sceneMemberID="firstResponder"/>
+            </objects>
+            <point key="canvasLocation" x="3388" y="734.48275862068965"/>
+        </scene>
         <!--Tab Bar View Controller-->
         <scene sceneID="nQ5-PV-qFw">
             <objects>
@@ -280,6 +371,7 @@
                     <connections>
                         <segue destination="lto-Zc-Vtp" kind="relationship" relationship="viewControllers" id="6hP-AH-YiH"/>
                         <segue destination="RpE-lI-27a" kind="relationship" relationship="viewControllers" id="g6X-Sq-uSW"/>
+                        <segue destination="pOk-Zm-vD9" kind="relationship" relationship="viewControllers" id="OPp-iO-iDK"/>
                     </connections>
                 </tabBarController>
                 <placeholder placeholderIdentifier="IBFirstResponder" id="Z9x-EI-p2b" userLabel="First Responder" sceneMemberID="firstResponder"/>
@@ -291,46 +383,53 @@
             <objects>
                 <viewController storyboardIdentifier="ModalViewController" id="bYI-y3-Rzb" customClass="ModalViewController" customModule="Samples" customModuleProvider="target" sceneMemberID="viewController">
                     <view key="view" contentMode="scaleToFill" id="qwo-GK-p1U">
-                        <rect key="frame" x="0.0" y="0.0" width="375" height="778"/>
+                        <rect key="frame" x="0.0" y="0.0" width="375" height="724"/>
                         <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                         <subviews>
                             <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="vut-mK-Y4t" customClass="SafeAreaView" customModule="Samples" customModuleProvider="target">
-                                <rect key="frame" x="0.0" y="744" width="375" height="34"/>
+                                <rect key="frame" x="0.0" y="724" width="375" height="0.0"/>
                                 <color key="backgroundColor" white="0.66666666666666663" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
                             </view>
-                            <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="roundedRect" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="sbF-Az-7sy">
-                                <rect key="frame" x="20" y="44" width="39" height="30"/>
+                            <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="system" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="sbF-Az-7sy">
+                                <rect key="frame" x="20" y="0.0" width="39" height="30"/>
                                 <state key="normal" title="Close"/>
                                 <connections>
                                     <action selector="closeWithSender:" destination="bYI-y3-Rzb" eventType="touchUpInside" id="MSC-ch-YJK"/>
                                 </connections>
                             </button>
                             <stackView opaque="NO" contentMode="scaleToFill" axis="vertical" alignment="top" spacing="44" translatesAutoresizingMaskIntoConstraints="NO" id="9p4-06-y2T">
-                                <rect key="frame" x="139.66666666666666" y="132" width="96" height="252"/>
+                                <rect key="frame" x="134.66666666666666" y="88" width="106" height="326"/>
                                 <subviews>
-                                    <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="roundedRect" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="i9x-x5-n1q">
+                                    <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="system" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="i9x-x5-n1q">
                                         <rect key="frame" x="0.0" y="0.0" width="80" height="30"/>
                                         <state key="normal" title="Move to full"/>
                                         <connections>
                                             <action selector="moveToFullWithSender:" destination="bYI-y3-Rzb" eventType="touchUpInside" id="TDe-3J-gIR"/>
                                         </connections>
                                     </button>
-                                    <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="roundedRect" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="2u5-cH-RAN">
+                                    <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="system" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="2u5-cH-RAN">
                                         <rect key="frame" x="0.0" y="74" width="85" height="30"/>
                                         <state key="normal" title="Move to half"/>
                                         <connections>
                                             <action selector="moveToHalfWithSender:" destination="bYI-y3-Rzb" eventType="touchUpInside" id="12s-o7-Et5"/>
                                         </connections>
                                     </button>
-                                    <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="roundedRect" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="M4A-iO-RIE">
+                                    <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="system" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="M4A-iO-RIE">
                                         <rect key="frame" x="0.0" y="148" width="77" height="30"/>
                                         <state key="normal" title="Move to tip"/>
                                         <connections>
                                             <action selector="moveToTipWithSender:" destination="bYI-y3-Rzb" eventType="touchUpInside" id="BmL-91-9ai"/>
                                         </connections>
                                     </button>
-                                    <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="roundedRect" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="szf-HE-QTk">
-                                        <rect key="frame" x="0.0" y="222" width="96" height="30"/>
+                                    <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="system" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="swr-XM-GzZ">
+                                        <rect key="frame" x="0.0" y="222" width="106" height="30"/>
+                                        <state key="normal" title="Move to hidden"/>
+                                        <connections>
+                                            <action selector="moveToHiddenWithSender:" destination="bYI-y3-Rzb" eventType="touchUpInside" id="jfJ-0f-fdk"/>
+                                        </connections>
+                                    </button>
+                                    <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="system" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="szf-HE-QTk">
+                                        <rect key="frame" x="0.0" y="296" width="96" height="30"/>
                                         <state key="normal" title="Update layout"/>
                                         <connections>
                                             <action selector="updateLayout:" destination="bYI-y3-Rzb" eventType="touchUpInside" id="Woz-a7-YMJ"/>
@@ -339,6 +438,7 @@
                                 </subviews>
                             </stackView>
                         </subviews>
+                        <viewLayoutGuide key="safeArea" id="kjr-TP-fcM"/>
                         <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
                         <constraints>
                             <constraint firstItem="sbF-Az-7sy" firstAttribute="top" secondItem="kjr-TP-fcM" secondAttribute="top" id="3VR-hj-zeQ"/>
@@ -350,7 +450,6 @@
                             <constraint firstItem="9p4-06-y2T" firstAttribute="centerX" secondItem="kjr-TP-fcM" secondAttribute="centerX" id="l8t-p3-ETf"/>
                             <constraint firstItem="vut-mK-Y4t" firstAttribute="top" secondItem="kjr-TP-fcM" secondAttribute="bottom" id="rMy-JT-t4B"/>
                         </constraints>
-                        <viewLayoutGuide key="safeArea" id="kjr-TP-fcM"/>
                     </view>
                     <size key="freeformSize" width="375" height="778"/>
                     <connections>
@@ -443,6 +542,7 @@
                                 </constraints>
                             </scrollView>
                         </subviews>
+                        <viewLayoutGuide key="safeArea" id="ufS-Rf-F2F"/>
                         <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
                         <gestureRecognizers/>
                         <constraints>
@@ -451,7 +551,6 @@
                             <constraint firstAttribute="bottom" secondItem="sBe-tN-uMi" secondAttribute="bottom" id="jzB-47-P7e"/>
                             <constraint firstItem="ufS-Rf-F2F" firstAttribute="trailing" secondItem="sBe-tN-uMi" secondAttribute="trailing" id="nHG-wg-pLP"/>
                         </constraints>
-                        <viewLayoutGuide key="safeArea" id="ufS-Rf-F2F"/>
                         <connections>
                             <outletCollection property="gestureRecognizers" destination="tOa-bf-zGz" appends="YES" id="zle-Sz-M3U"/>
                             <outletCollection property="gestureRecognizers" destination="SCk-hG-weZ" appends="YES" id="OcK-FK-Lac"/>
@@ -499,10 +598,10 @@
                                 </constraints>
                             </view>
                             <view alpha="0.5" contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="Kva-Z7-0qY" customClass="OnSafeAreaView" customModule="Samples" customModuleProvider="target">
-                                <rect key="frame" x="0.0" y="44" width="375" height="700"/>
+                                <rect key="frame" x="0.0" y="44" width="375" height="734"/>
                                 <color key="backgroundColor" red="0.0078431372550000003" green="0.72156862749999995" blue="0.45882352939999999" alpha="1" colorSpace="calibratedRGB"/>
                             </view>
-                            <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="roundedRect" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="noi-1a-5bZ" customClass="CloseButton" customModule="Samples" customModuleProvider="target">
+                            <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="system" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="noi-1a-5bZ" customClass="CloseButton" customModule="Samples" customModuleProvider="target">
                                 <rect key="frame" x="319" y="44" width="44" height="44"/>
                                 <constraints>
                                     <constraint firstAttribute="height" constant="44" id="0jg-5D-A1F"/>
@@ -512,17 +611,34 @@
                                     <action selector="closeWithSender:" destination="YC8-ae-15L" eventType="touchUpInside" id="Z2v-19-S5k"/>
                                 </connections>
                             </button>
-                            <stackView opaque="NO" contentMode="scaleToFill" axis="vertical" spacing="22" translatesAutoresizingMaskIntoConstraints="NO" id="tP3-oJ-4EB">
-                                <rect key="frame" x="130.66666666666666" y="132" width="114" height="134"/>
+                            <stackView opaque="NO" contentMode="scaleToFill" distribution="fillProportionally" alignment="center" spacing="8" translatesAutoresizingMaskIntoConstraints="NO" id="qux-uG-4o2">
+                                <rect key="frame" x="8" y="52" width="148" height="31"/>
                                 <subviews>
-                                    <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="roundedRect" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="c5r-jU-haj">
+                                    <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="fitToBounds" textAlignment="natural" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="7lq-d3-PKi">
+                                        <rect key="frame" x="0.0" y="5.3333333333333357" width="91" height="20.333333333333332"/>
+                                        <fontDescription key="fontDescription" type="system" pointSize="17"/>
+                                        <nil key="textColor"/>
+                                        <nil key="highlightedColor"/>
+                                    </label>
+                                    <switch opaque="NO" contentMode="scaleToFill" horizontalHuggingPriority="750" verticalHuggingPriority="750" contentHorizontalAlignment="center" contentVerticalAlignment="center" on="YES" translatesAutoresizingMaskIntoConstraints="NO" id="0MA-lV-KjS">
+                                        <rect key="frame" x="99" y="0.0" width="51" height="31"/>
+                                        <connections>
+                                            <action selector="modeChanged:" destination="YC8-ae-15L" eventType="valueChanged" id="IQ8-u2-Rib"/>
+                                        </connections>
+                                    </switch>
+                                </subviews>
+                            </stackView>
+                            <stackView opaque="NO" contentMode="scaleToFill" axis="vertical" spacing="22" translatesAutoresizingMaskIntoConstraints="NO" id="tP3-oJ-4EB">
+                                <rect key="frame" x="130.66666666666666" y="88" width="114" height="134"/>
+                                <subviews>
+                                    <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="system" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="c5r-jU-haj">
                                         <rect key="frame" x="0.0" y="0.0" width="114" height="30"/>
                                         <state key="normal" title="Show"/>
                                         <connections>
                                             <action selector="buttonPressed:" destination="YC8-ae-15L" eventType="touchUpInside" id="Mi1-o6-TWt"/>
                                         </connections>
                                     </button>
-                                    <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="roundedRect" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="wmd-ab-Nz3">
+                                    <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="system" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="wmd-ab-Nz3">
                                         <rect key="frame" x="0.0" y="52" width="114" height="30"/>
                                         <state key="normal" title="Present Modallly"/>
                                         <connections>
@@ -530,7 +646,7 @@
                                             <segue destination="bYI-y3-Rzb" kind="presentation" identifier="PresentModallySegue" id="3yq-HE-Tgn"/>
                                         </connections>
                                     </button>
-                                    <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="roundedRect" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="01L-lp-oy6">
+                                    <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="system" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="01L-lp-oy6">
                                         <rect key="frame" x="0.0" y="104" width="114" height="30"/>
                                         <state key="normal" title="Update Layout"/>
                                         <connections>
@@ -540,6 +656,7 @@
                                 </subviews>
                             </stackView>
                         </subviews>
+                        <viewLayoutGuide key="safeArea" id="aOK-7l-cA6"/>
                         <color key="backgroundColor" red="1" green="0.83234566450000003" blue="0.47320586440000001" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
                         <gestureRecognizers/>
                         <constraints>
@@ -549,14 +666,15 @@
                             <constraint firstItem="8yw-OC-Ubk" firstAttribute="bottom" secondItem="g7l-kO-y7q" secondAttribute="bottom" id="JOL-wC-w74"/>
                             <constraint firstItem="8yw-OC-Ubk" firstAttribute="leading" secondItem="aOK-7l-cA6" secondAttribute="leading" id="RiJ-Hb-OOZ"/>
                             <constraint firstItem="8yw-OC-Ubk" firstAttribute="trailing" secondItem="aOK-7l-cA6" secondAttribute="trailing" id="Sof-yL-mwK"/>
-                            <constraint firstItem="tP3-oJ-4EB" firstAttribute="top" secondItem="aOK-7l-cA6" secondAttribute="top" constant="88" id="Zhb-Ss-epe"/>
+                            <constraint firstItem="tP3-oJ-4EB" firstAttribute="top" secondItem="g7l-kO-y7q" secondAttribute="top" constant="88" id="Zhb-Ss-epe"/>
                             <constraint firstItem="Kva-Z7-0qY" firstAttribute="trailing" secondItem="aOK-7l-cA6" secondAttribute="trailing" id="kkp-Yo-FQW"/>
                             <constraint firstItem="aOK-7l-cA6" firstAttribute="trailing" secondItem="noi-1a-5bZ" secondAttribute="trailing" constant="12" id="lv9-Nf-HNB"/>
+                            <constraint firstItem="qux-uG-4o2" firstAttribute="top" secondItem="aOK-7l-cA6" secondAttribute="top" constant="8" id="naa-cf-ZIc"/>
                             <constraint firstItem="Kva-Z7-0qY" firstAttribute="leading" secondItem="aOK-7l-cA6" secondAttribute="leading" id="oVC-i1-TwS"/>
                             <constraint firstItem="aOK-7l-cA6" firstAttribute="bottom" secondItem="Kva-Z7-0qY" secondAttribute="bottom" id="rW2-mF-5DR"/>
                             <constraint firstItem="8yw-OC-Ubk" firstAttribute="top" relation="greaterThanOrEqual" secondItem="tP3-oJ-4EB" secondAttribute="bottom" constant="88" id="vKQ-h9-uKt"/>
+                            <constraint firstItem="qux-uG-4o2" firstAttribute="leading" secondItem="g7l-kO-y7q" secondAttribute="leading" constant="8" id="zXb-R9-bMO"/>
                         </constraints>
-                        <viewLayoutGuide key="safeArea" id="aOK-7l-cA6"/>
                         <connections>
                             <outletCollection property="gestureRecognizers" destination="6Ca-p8-7uF" appends="YES" id="xOy-f1-NZE"/>
                             <outletCollection property="gestureRecognizers" destination="SPY-Vr-XDT" appends="YES" id="vgS-Am-jhQ"/>
@@ -566,6 +684,8 @@
                     <size key="freeformSize" width="375" height="778"/>
                     <connections>
                         <outlet property="closeButton" destination="noi-1a-5bZ" id="eWQ-ha-8y7"/>
+                        <outlet property="intrinsicHeightConstraint" destination="vKQ-h9-uKt" id="QpA-WD-b17"/>
+                        <outlet property="modeChangeView" destination="qux-uG-4o2" id="1Nq-fE-dXw"/>
                         <segue destination="bYI-y3-Rzb" kind="show" identifier="ShowSegue" id="r1P-2i-NDe"/>
                     </connections>
                 </viewController>
@@ -586,7 +706,7 @@
                     </connections>
                 </pongPressGestureRecognizer>
             </objects>
-            <point key="canvasLocation" x="655" y="734"/>
+            <point key="canvasLocation" x="653.60000000000002" y="733.74384236453204"/>
         </scene>
         <!--Debug Text View Controller-->
         <scene sceneID="Bkq-O7-q4A">
@@ -642,6 +762,7 @@ Section 1.10.33 of "de Finibus Bonorum et Malorum", written by Cicero in 45 BC
                                 <textInputTraits key="textInputTraits" autocapitalizationType="sentences"/>
                             </textView>
                         </subviews>
+                        <viewLayoutGuide key="safeArea" id="5ET-zC-lCb"/>
                         <color key="backgroundColor" white="0.0" alpha="0.0" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
                         <constraints>
                             <constraint firstItem="rN1-HL-YHv" firstAttribute="leading" secondItem="5ET-zC-lCb" secondAttribute="leading" id="7V3-KL-vXd"/>
@@ -649,11 +770,12 @@ Section 1.10.33 of "de Finibus Bonorum et Malorum", written by Cicero in 45 BC
                             <constraint firstItem="rN1-HL-YHv" firstAttribute="top" secondItem="9YG-0j-Zzg" secondAttribute="top" constant="17" id="fiO-LL-nSC"/>
                             <constraint firstItem="rN1-HL-YHv" firstAttribute="trailing" secondItem="5ET-zC-lCb" secondAttribute="trailing" id="lfg-EE-euw"/>
                         </constraints>
-                        <viewLayoutGuide key="safeArea" id="5ET-zC-lCb"/>
                     </view>
                     <size key="freeformSize" width="375" height="778"/>
                     <connections>
                         <outlet property="textView" destination="rN1-HL-YHv" id="gmr-Uf-jd8"/>
+                        <outlet property="textViewTopConstraint" destination="fiO-LL-nSC" id="Rum-TN-c2e"/>
+                        <outlet property="view" destination="9YG-0j-Zzg" id="jhb-eT-nEn"/>
                     </connections>
                 </viewController>
                 <placeholder placeholderIdentifier="IBFirstResponder" id="x1h-y1-h8q" userLabel="First Responder" sceneMemberID="firstResponder"/>
@@ -661,7 +783,27 @@ Section 1.10.33 of "de Finibus Bonorum et Malorum", written by Cicero in 45 BC
             <point key="canvasLocation" x="-1" y="734"/>
         </scene>
     </scenes>
+    <designables>
+        <designable name="noi-1a-5bZ">
+            <size key="intrinsicContentSize" width="30" height="30"/>
+        </designable>
+    </designables>
     <inferredMetricsTieBreakers>
         <segue reference="r1P-2i-NDe"/>
     </inferredMetricsTieBreakers>
+    <resources>
+        <image name="IMG_0003" width="750" height="501"/>
+        <systemColor name="systemBackgroundColor">
+            <color white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
+        </systemColor>
+        <systemColor name="systemOrangeColor">
+            <color red="1" green="0.58431372549019611" blue="0.0" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
+        </systemColor>
+        <systemColor name="systemPurpleColor">
+            <color red="0.68627450980392157" green="0.32156862745098042" blue="0.87058823529411766" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
+        </systemColor>
+        <systemColor name="systemTealColor">
+            <color red="0.35294117647058826" green="0.78431372549019607" blue="0.98039215686274506" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
+        </systemColor>
+    </resources>
 </document>

Examples/Samples/Sources/Extensions.swift

@@ -1,7 +1,4 @@
-//
-//  Created by Shin Yamamoto on 2018/10/08.
-//  Copyright © 2018 Shin Yamamoto. All rights reserved.
-//
+// Copyright 2018 the FloatingPanel authors. All rights reserved. MIT license.
 
 import UIKit
 

Examples/Samples/Sources/UIComponents.swift

@@ -1,7 +1,4 @@
-//
-//  Created by Shin Yamamoto on 2018/09/19.
-//  Copyright © 2018 Shin Yamamoto. All rights reserved.
-//
+// Copyright 2018 the FloatingPanel authors. All rights reserved. MIT license.
 
 import UIKit
 

Examples/Samples/Sources/UseCases/CustomState.swift

@@ -0,0 +1,22 @@
+// Copyright 2018-Present Shin Yamamoto. All rights reserved. MIT license.
+
+import Foundation
+import FloatingPanel
+
+extension FloatingPanelState {
+    static let lastQuart: FloatingPanelState = FloatingPanelState(rawValue: "lastQuart", order: 750)
+    static let firstQuart: FloatingPanelState = FloatingPanelState(rawValue: "firstQuart", order: 250)
+}
+
+class FloatingPanelLayoutWithCustomState: FloatingPanelBottomLayout {
+    override var anchors: [FloatingPanelState: FloatingPanelLayoutAnchoring] {
+        return [
+            .full: FloatingPanelLayoutAnchor(absoluteInset: 0.0, edge: .top, referenceGuide: .safeArea),
+            .lastQuart: FloatingPanelLayoutAnchor(fractionalInset: 0.75, edge: .bottom, referenceGuide: .safeArea),
+            .half: FloatingPanelLayoutAnchor(fractionalInset: 0.5, edge: .bottom, referenceGuide: .safeArea),
+            .firstQuart: FloatingPanelLayoutAnchor(fractionalInset: 0.25, edge: .bottom, referenceGuide: .safeArea),
+            .tip: FloatingPanelLayoutAnchor(absoluteInset: 20.0, edge: .bottom, referenceGuide: .safeArea),
+        ]
+    }
+}
+

Examples/Samples/Sources/UseCases/UseCases.swift

@@ -0,0 +1,78 @@
+// Copyright 2018-Present Shin Yamamoto. All rights reserved. MIT license.
+
+import Foundation
+
+enum UseCases: Int, CaseIterable {
+    case trackingTableView
+    case trackingTextView
+    case showDetail
+    case showModal
+    case showPanelModal
+    case showMultiPanelModal
+    case showPanelInSheetModal
+    case showTabBar
+    case showPageView
+    case showPageContentView
+    case showNestedScrollView
+    case showRemovablePanel
+    case showIntrinsicView
+    case showContentInset
+    case showContainerMargins
+    case showNavigationController
+    case showTopPositionedPanel
+    case showAdaptivePanel
+    case showAdaptivePanelWithCustomGuide
+    case showCustomStatePanel
+
+    var name: String {
+        switch self {
+        case .trackingTableView: return "Scroll tracking(TableView)"
+        case .trackingTextView: return "Scroll tracking(TextView)"
+        case .showDetail: return "Show Detail Panel"
+        case .showModal: return "Show Modal"
+        case .showPanelModal: return "Show Panel Modal"
+        case .showMultiPanelModal: return "Show Multi Panel Modal"
+        case .showPanelInSheetModal: return "Show Panel in Sheet Modal"
+        case .showTabBar: return "Show Tab Bar"
+        case .showPageView: return "Show Page View"
+        case .showPageContentView: return "Show Page Content View"
+        case .showNestedScrollView: return "Show Nested ScrollView"
+        case .showRemovablePanel: return "Show Removable Panel"
+        case .showIntrinsicView: return "Show Intrinsic View"
+        case .showContentInset: return "Show with ContentInset"
+        case .showContainerMargins: return "Show with ContainerMargins"
+        case .showNavigationController: return "Show Navigation Controller"
+        case .showTopPositionedPanel: return "Show Top Positioned Panel"
+        case .showAdaptivePanel: return "Show Adaptive Panel"
+        case .showAdaptivePanelWithCustomGuide: return "Show Adaptive Panel (Custom Layout Guide)"
+        case .showCustomStatePanel: return "Show Panel with Custom state"
+        }
+    }
+
+    var storyboardID: String? {
+        switch self {
+        case .trackingTableView: return nil
+        case .trackingTextView: return "ConsoleViewController"
+        case .showDetail: return "DetailViewController"
+        case .showModal: return "ModalViewController"
+        case .showMultiPanelModal: return nil
+        case .showPanelInSheetModal: return nil
+        case .showPanelModal: return nil
+        case .showTabBar: return "TabBarViewController"
+        case .showPageView: return nil
+        case .showPageContentView: return nil
+        case .showNestedScrollView: return "NestedScrollViewController"
+        case .showRemovablePanel: return "DetailViewController"
+        case .showIntrinsicView: return "IntrinsicViewController"
+        case .showContentInset: return nil
+        case .showContainerMargins: return nil
+        case .showNavigationController: return "RootNavigationController"
+        case .showTopPositionedPanel: return nil
+        case .showAdaptivePanel,
+             .showAdaptivePanelWithCustomGuide:
+            return "ImageViewController"
+        case .showCustomStatePanel:
+            return nil
+        }
+    }
+}

Examples/Samples/Tests/SampleTests.swift

@@ -1,10 +1,4 @@
-//
-//  FloatingModalSampleTests.swift
-//  FloatingModalSampleTests
-//
-//  Created by Shin Yamamoto on 2018/09/18.
-//  Copyright © 2018 Shin Yamamoto. All rights reserved.
-//
+// Copyright 2018 the FloatingPanel authors. All rights reserved. MIT license.
 
 import XCTest
 @testable import FloatingPanelSample

Examples/Samples/UITests/SampleUITests.swift

@@ -1,7 +1,4 @@
-//
-//  Created by Shin Yamamoto on 2018/09/18.
-//  Copyright © 2018 Shin Yamamoto. All rights reserved.
-//
+// Copyright 2018 the FloatingPanel authors. All rights reserved. MIT license.
 
 import XCTest
 

Examples/SamplesObjC/SamplesObjC.xcodeproj/project.pbxproj

@@ -0,0 +1,375 @@
+// !$*UTF8*$!
+{
+	archiveVersion = 1;
+	classes = {
+	};
+	objectVersion = 50;
+	objects = {
+
+/* Begin PBXBuildFile section */
+		545BA70621BA3214007F7846 /* AppDelegate.m in Sources */ = {isa = PBXBuildFile; fileRef = 545BA70521BA3214007F7846 /* AppDelegate.m */; };
+		545BA70921BA3214007F7846 /* ViewController.m in Sources */ = {isa = PBXBuildFile; fileRef = 545BA70821BA3214007F7846 /* ViewController.m */; };
+		545BA70C21BA3214007F7846 /* Main.storyboard in Resources */ = {isa = PBXBuildFile; fileRef = 545BA70A21BA3214007F7846 /* Main.storyboard */; };
+		545BA70E21BA3217007F7846 /* Assets.xcassets in Resources */ = {isa = PBXBuildFile; fileRef = 545BA70D21BA3217007F7846 /* Assets.xcassets */; };
+		545BA71121BA3217007F7846 /* LaunchScreen.storyboard in Resources */ = {isa = PBXBuildFile; fileRef = 545BA70F21BA3217007F7846 /* LaunchScreen.storyboard */; };
+		545BA71421BA3217007F7846 /* main.m in Sources */ = {isa = PBXBuildFile; fileRef = 545BA71321BA3217007F7846 /* main.m */; };
+		545BA72621BA3BAF007F7846 /* FloatingPanel.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 545BA72521BA3BAF007F7846 /* FloatingPanel.framework */; };
+		545BA72721BA3BAF007F7846 /* FloatingPanel.framework in Embed Frameworks */ = {isa = PBXBuildFile; fileRef = 545BA72521BA3BAF007F7846 /* FloatingPanel.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
+/* End PBXBuildFile section */
+
+/* Begin PBXCopyFilesBuildPhase section */
+		545BA72821BA3BAF007F7846 /* Embed Frameworks */ = {
+			isa = PBXCopyFilesBuildPhase;
+			buildActionMask = 2147483647;
+			dstPath = "";
+			dstSubfolderSpec = 10;
+			files = (
+				545BA72721BA3BAF007F7846 /* FloatingPanel.framework in Embed Frameworks */,
+			);
+			name = "Embed Frameworks";
+			runOnlyForDeploymentPostprocessing = 0;
+		};
+/* End PBXCopyFilesBuildPhase section */
+
+/* Begin PBXFileReference section */
+		545BA70121BA3214007F7846 /* SamplesObjC.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = SamplesObjC.app; sourceTree = BUILT_PRODUCTS_DIR; };
+		545BA70421BA3214007F7846 /* AppDelegate.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = AppDelegate.h; sourceTree = "<group>"; };
+		545BA70521BA3214007F7846 /* AppDelegate.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = AppDelegate.m; sourceTree = "<group>"; };
+		545BA70721BA3214007F7846 /* ViewController.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = ViewController.h; sourceTree = "<group>"; };
+		545BA70821BA3214007F7846 /* ViewController.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = ViewController.m; sourceTree = "<group>"; };
+		545BA70B21BA3214007F7846 /* Base */ = {isa = PBXFileReference; lastKnownFileType = file.storyboard; name = Base; path = Base.lproj/Main.storyboard; sourceTree = "<group>"; };
+		545BA70D21BA3217007F7846 /* Assets.xcassets */ = {isa = PBXFileReference; lastKnownFileType = folder.assetcatalog; path = Assets.xcassets; sourceTree = "<group>"; };
+		545BA71021BA3217007F7846 /* Base */ = {isa = PBXFileReference; lastKnownFileType = file.storyboard; name = Base; path = Base.lproj/LaunchScreen.storyboard; sourceTree = "<group>"; };
+		545BA71221BA3217007F7846 /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
+		545BA71321BA3217007F7846 /* main.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = main.m; sourceTree = "<group>"; };
+		545BA72221BA3867007F7846 /* SamplesObjC-Bridging-Header.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = "SamplesObjC-Bridging-Header.h"; sourceTree = "<group>"; };
+		545BA72521BA3BAF007F7846 /* FloatingPanel.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; path = FloatingPanel.framework; sourceTree = BUILT_PRODUCTS_DIR; };
+/* End PBXFileReference section */
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+			isa = PBXGroup;
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+				545BA71221BA3217007F7846 /* Info.plist */,
+				545BA71321BA3217007F7846 /* main.m */,
+				545BA72221BA3867007F7846 /* SamplesObjC-Bridging-Header.h */,
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+			);
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+			);
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+				545BA71121BA3217007F7846 /* LaunchScreen.storyboard in Resources */,
+				545BA70E21BA3217007F7846 /* Assets.xcassets in Resources */,
+				545BA70C21BA3214007F7846 /* Main.storyboard in Resources */,
+			);
+			runOnlyForDeploymentPostprocessing = 0;
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+/* Begin PBXSourcesBuildPhase section */
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+				545BA70921BA3214007F7846 /* ViewController.m in Sources */,
+				545BA71421BA3217007F7846 /* main.m in Sources */,
+				545BA70621BA3214007F7846 /* AppDelegate.m in Sources */,
+			);
+			runOnlyForDeploymentPostprocessing = 0;
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+/* End PBXSourcesBuildPhase section */
+
+/* Begin PBXVariantGroup section */
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+			children = (
+				545BA70B21BA3214007F7846 /* Base */,
+			);
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+			sourceTree = "<group>";
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+		545BA70F21BA3217007F7846 /* LaunchScreen.storyboard */ = {
+			isa = PBXVariantGroup;
+			children = (
+				545BA71021BA3217007F7846 /* Base */,
+			);
+			name = LaunchScreen.storyboard;
+			sourceTree = "<group>";
+		};
+/* End PBXVariantGroup section */
+
+/* Begin XCBuildConfiguration section */
+		545BA71521BA3217007F7846 /* Debug */ = {
+			isa = XCBuildConfiguration;
+			buildSettings = {
+				ALWAYS_SEARCH_USER_PATHS = NO;
+				CLANG_ANALYZER_NONNULL = YES;
+				CLANG_ANALYZER_NUMBER_OBJECT_CONVERSION = YES_AGGRESSIVE;
+				CLANG_CXX_LANGUAGE_STANDARD = "gnu++14";
+				CLANG_CXX_LIBRARY = "libc++";
+				CLANG_ENABLE_MODULES = YES;
+				CLANG_ENABLE_OBJC_ARC = YES;
+				CLANG_ENABLE_OBJC_WEAK = YES;
+				CLANG_WARN_BLOCK_CAPTURE_AUTORELEASING = YES;
+				CLANG_WARN_BOOL_CONVERSION = YES;
+				CLANG_WARN_COMMA = YES;
+				CLANG_WARN_CONSTANT_CONVERSION = YES;
+				CLANG_WARN_DEPRECATED_OBJC_IMPLEMENTATIONS = YES;
+				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
+				CLANG_WARN_DOCUMENTATION_COMMENTS = YES;
+				CLANG_WARN_EMPTY_BODY = YES;
+				CLANG_WARN_ENUM_CONVERSION = YES;
+				CLANG_WARN_INFINITE_RECURSION = YES;
+				CLANG_WARN_INT_CONVERSION = YES;
+				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES;
+				CLANG_WARN_OBJC_IMPLICIT_RETAIN_SELF = YES;
+				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
+				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
+				CLANG_WARN_STRICT_PROTOTYPES = YES;
+				CLANG_WARN_SUSPICIOUS_MOVE = YES;
+				CLANG_WARN_UNGUARDED_AVAILABILITY = YES_AGGRESSIVE;
+				CLANG_WARN_UNREACHABLE_CODE = YES;
+				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
+				CODE_SIGN_IDENTITY = "iPhone Developer";
+				COPY_PHASE_STRIP = NO;
+				DEBUG_INFORMATION_FORMAT = dwarf;
+				ENABLE_STRICT_OBJC_MSGSEND = YES;
+				ENABLE_TESTABILITY = YES;
+				GCC_C_LANGUAGE_STANDARD = gnu11;
+				GCC_DYNAMIC_NO_PIC = NO;
+				GCC_NO_COMMON_BLOCKS = YES;
+				GCC_OPTIMIZATION_LEVEL = 0;
+				GCC_PREPROCESSOR_DEFINITIONS = (
+					"DEBUG=1",
+					"$(inherited)",
+				);
+				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
+				GCC_WARN_ABOUT_RETURN_TYPE = YES_ERROR;
+				GCC_WARN_UNDECLARED_SELECTOR = YES;
+				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
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+				MTL_ENABLE_DEBUG_INFO = INCLUDE_SOURCE;
+				MTL_FAST_MATH = YES;
+				ONLY_ACTIVE_ARCH = YES;
+				SDKROOT = iphoneos;
+			};
+			name = Debug;
+		};
+		545BA71621BA3217007F7846 /* Release */ = {
+			isa = XCBuildConfiguration;
+			buildSettings = {
+				ALWAYS_SEARCH_USER_PATHS = NO;
+				CLANG_ANALYZER_NONNULL = YES;
+				CLANG_ANALYZER_NUMBER_OBJECT_CONVERSION = YES_AGGRESSIVE;
+				CLANG_CXX_LANGUAGE_STANDARD = "gnu++14";
+				CLANG_CXX_LIBRARY = "libc++";
+				CLANG_ENABLE_MODULES = YES;
+				CLANG_ENABLE_OBJC_ARC = YES;
+				CLANG_ENABLE_OBJC_WEAK = YES;
+				CLANG_WARN_BLOCK_CAPTURE_AUTORELEASING = YES;
+				CLANG_WARN_BOOL_CONVERSION = YES;
+				CLANG_WARN_COMMA = YES;
+				CLANG_WARN_CONSTANT_CONVERSION = YES;
+				CLANG_WARN_DEPRECATED_OBJC_IMPLEMENTATIONS = YES;
+				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
+				CLANG_WARN_DOCUMENTATION_COMMENTS = YES;
+				CLANG_WARN_EMPTY_BODY = YES;
+				CLANG_WARN_ENUM_CONVERSION = YES;
+				CLANG_WARN_INFINITE_RECURSION = YES;
+				CLANG_WARN_INT_CONVERSION = YES;
+				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES;
+				CLANG_WARN_OBJC_IMPLICIT_RETAIN_SELF = YES;
+				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
+				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
+				CLANG_WARN_STRICT_PROTOTYPES = YES;
+				CLANG_WARN_SUSPICIOUS_MOVE = YES;
+				CLANG_WARN_UNGUARDED_AVAILABILITY = YES_AGGRESSIVE;
+				CLANG_WARN_UNREACHABLE_CODE = YES;
+				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
+				CODE_SIGN_IDENTITY = "iPhone Developer";
+				COPY_PHASE_STRIP = NO;
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+				GCC_NO_COMMON_BLOCKS = YES;
+				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
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+				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
+				GCC_WARN_UNUSED_FUNCTION = YES;
+				GCC_WARN_UNUSED_VARIABLE = YES;
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+				MTL_ENABLE_DEBUG_INFO = NO;
+				MTL_FAST_MATH = YES;
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+				SWIFT_COMPILATION_MODE = wholemodule;
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+			};
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+		};
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+			isa = XCBuildConfiguration;
+			buildSettings = {
+				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
+				CLANG_ENABLE_MODULES = YES;
+				CODE_SIGN_STYLE = Automatic;
+				DEFINES_MODULE = NO;
+				DEVELOPMENT_TEAM = J3D7L9FHSS;
+				INFOPLIST_FILE = SamplesObjC/Info.plist;
+				LD_RUNPATH_SEARCH_PATHS = (
+					"$(inherited)",
+					"@executable_path/Frameworks",
+				);
+				PRODUCT_BUNDLE_IDENTIFIER = com.scenee.SamplesObjC;
+				PRODUCT_NAME = "$(TARGET_NAME)";
+				SWIFT_OBJC_BRIDGING_HEADER = "SamplesObjC/SamplesObjC-Bridging-Header.h";
+				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
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+		};
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+			buildSettings = {
+				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
+				CLANG_ENABLE_MODULES = YES;
+				CODE_SIGN_STYLE = Automatic;
+				DEFINES_MODULE = NO;
+				DEVELOPMENT_TEAM = J3D7L9FHSS;
+				INFOPLIST_FILE = SamplesObjC/Info.plist;
+				LD_RUNPATH_SEARCH_PATHS = (
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+					"@executable_path/Frameworks",
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+				PRODUCT_BUNDLE_IDENTIFIER = com.scenee.SamplesObjC;
+				PRODUCT_NAME = "$(TARGET_NAME)";
+				SWIFT_OBJC_BRIDGING_HEADER = "SamplesObjC/SamplesObjC-Bridging-Header.h";
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+				TARGETED_DEVICE_FAMILY = "1,2";
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+			name = Release;
+		};
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+
+/* Begin XCConfigurationList section */
+		545BA6FC21BA3214007F7846 /* Build configuration list for PBXProject "SamplesObjC" */ = {
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+			buildConfigurations = (
+				545BA71521BA3217007F7846 /* Debug */,
+				545BA71621BA3217007F7846 /* Release */,
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+			defaultConfigurationIsVisible = 0;
+			defaultConfigurationName = Release;
+		};
+		545BA71721BA3217007F7846 /* Build configuration list for PBXNativeTarget "SamplesObjC" */ = {
+			isa = XCConfigurationList;
+			buildConfigurations = (
+				545BA71821BA3217007F7846 /* Debug */,
+				545BA71921BA3217007F7846 /* Release */,
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+			defaultConfigurationName = Release;
+		};
+/* End XCConfigurationList section */
+	};
+	rootObject = 545BA6F921BA3214007F7846 /* Project object */;
+}

Examples/SamplesObjC/SamplesObjC.xcodeproj/project.xcworkspace/contents.xcworkspacedata

@@ -2,6 +2,6 @@
 <Workspace
    version = "1.0">
    <FileRef
-      location = "self:FloatingModalController.xcodeproj">
+      location = "self:SamplesObjC.xcodeproj">
    </FileRef>
 </Workspace>

Examples/SamplesObjC/SamplesObjC.xcodeproj/xcshareddata/xcschemes/SamplesObjC.xcscheme

@@ -0,0 +1,87 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Scheme
+   LastUpgradeVersion = "1110"
+   version = "1.3">
+   <BuildAction
+      parallelizeBuildables = "YES"
+      buildImplicitDependencies = "YES">
+      <BuildActionEntries>
+         <BuildActionEntry
+            buildForTesting = "YES"
+            buildForRunning = "YES"
+            buildForProfiling = "YES"
+            buildForArchiving = "YES"
+            buildForAnalyzing = "YES">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "545BA70021BA3214007F7846"
+               BuildableName = "SamplesObjC.app"
+               BlueprintName = "SamplesObjC"
+               ReferencedContainer = "container:SamplesObjC.xcodeproj">
+            </BuildableReference>
+         </BuildActionEntry>
+      </BuildActionEntries>
+   </BuildAction>
+   <TestAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      shouldUseLaunchSchemeArgsEnv = "YES">
+      <MacroExpansion>
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "545BA70021BA3214007F7846"
+            BuildableName = "SamplesObjC.app"
+            BlueprintName = "SamplesObjC"
+            ReferencedContainer = "container:SamplesObjC.xcodeproj">
+         </BuildableReference>
+      </MacroExpansion>
+      <Testables>
+      </Testables>
+   </TestAction>
+   <LaunchAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      launchStyle = "0"
+      useCustomWorkingDirectory = "NO"
+      ignoresPersistentStateOnLaunch = "NO"
+      debugDocumentVersioning = "YES"
+      debugServiceExtension = "internal"
+      allowLocationSimulation = "YES">
+      <BuildableProductRunnable
+         runnableDebuggingMode = "0">
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "545BA70021BA3214007F7846"
+            BuildableName = "SamplesObjC.app"
+            BlueprintName = "SamplesObjC"
+            ReferencedContainer = "container:SamplesObjC.xcodeproj">
+         </BuildableReference>
+      </BuildableProductRunnable>
+   </LaunchAction>
+   <ProfileAction
+      buildConfiguration = "Release"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      savedToolIdentifier = ""
+      useCustomWorkingDirectory = "NO"
+      debugDocumentVersioning = "YES">
+      <BuildableProductRunnable
+         runnableDebuggingMode = "0">
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "545BA70021BA3214007F7846"
+            BuildableName = "SamplesObjC.app"
+            BlueprintName = "SamplesObjC"
+            ReferencedContainer = "container:SamplesObjC.xcodeproj">
+         </BuildableReference>
+      </BuildableProductRunnable>
+   </ProfileAction>
+   <AnalyzeAction
+      buildConfiguration = "Debug">
+   </AnalyzeAction>
+   <ArchiveAction
+      buildConfiguration = "Release"
+      revealArchiveInOrganizer = "YES">
+   </ArchiveAction>
+</Scheme>

Examples/SamplesObjC/SamplesObjC/AppDelegate.h

@@ -0,0 +1,9 @@
+// Copyright 2018 the FloatingPanel authors. All rights reserved. MIT license.
+
+#import <UIKit/UIKit.h>
+
+@interface AppDelegate : UIResponder <UIApplicationDelegate>
+
+@property (strong, nonatomic) UIWindow* window;
+
+@end

Examples/SamplesObjC/SamplesObjC/AppDelegate.m

@@ -0,0 +1,9 @@
+// Copyright 2018 the FloatingPanel authors. All rights reserved. MIT license.
+
+#import "AppDelegate.h"
+
+@interface AppDelegate ()
+@end
+
+@implementation AppDelegate
+@end

Examples/SamplesObjC/SamplesObjC/Assets.xcassets/AppIcon.appiconset/Contents.json

@@ -0,0 +1,98 @@
+{
+  "images" : [
+    {
+      "idiom" : "iphone",
+      "size" : "20x20",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "iphone",
+      "size" : "20x20",
+      "scale" : "3x"
+    },
+    {
+      "idiom" : "iphone",
+      "size" : "29x29",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "iphone",
+      "size" : "29x29",
+      "scale" : "3x"
+    },
+    {
+      "idiom" : "iphone",
+      "size" : "40x40",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "iphone",
+      "size" : "40x40",
+      "scale" : "3x"
+    },
+    {
+      "idiom" : "iphone",
+      "size" : "60x60",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "iphone",
+      "size" : "60x60",
+      "scale" : "3x"
+    },
+    {
+      "idiom" : "ipad",
+      "size" : "20x20",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "ipad",
+      "size" : "20x20",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "ipad",
+      "size" : "29x29",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "ipad",
+      "size" : "29x29",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "ipad",
+      "size" : "40x40",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "ipad",
+      "size" : "40x40",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "ipad",
+      "size" : "76x76",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "ipad",
+      "size" : "76x76",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "ipad",
+      "size" : "83.5x83.5",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "ios-marketing",
+      "size" : "1024x1024",
+      "scale" : "1x"
+    }
+  ],
+  "info" : {
+    "version" : 1,
+    "author" : "xcode"
+  }
+}

Examples/SamplesObjC/SamplesObjC/Assets.xcassets/Contents.json

@@ -0,0 +1,6 @@
+{
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

Examples/SamplesObjC/SamplesObjC/Base.lproj/LaunchScreen.storyboard

@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="13122.16" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" launchScreen="YES" useTraitCollections="YES" useSafeAreas="YES" colorMatched="YES" initialViewController="01J-lp-oVM">
+    <dependencies>
+        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="13104.12"/>
+        <capability name="Safe area layout guides" minToolsVersion="9.0"/>
+        <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
+    </dependencies>
+    <scenes>
+        <!--View Controller-->
+        <scene sceneID="EHf-IW-A2E">
+            <objects>
+                <viewController id="01J-lp-oVM" sceneMemberID="viewController">
+                    <view key="view" contentMode="scaleToFill" id="Ze5-6b-2t3">
+                        <rect key="frame" x="0.0" y="0.0" width="375" height="667"/>
+                        <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
+                        <color key="backgroundColor" red="1" green="1" blue="1" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
+                        <viewLayoutGuide key="safeArea" id="6Tk-OE-BBY"/>
+                    </view>
+                </viewController>
+                <placeholder placeholderIdentifier="IBFirstResponder" id="iYj-Kq-Ea1" userLabel="First Responder" sceneMemberID="firstResponder"/>
+            </objects>
+            <point key="canvasLocation" x="53" y="375"/>
+        </scene>
+    </scenes>
+</document>

Examples/SamplesObjC/SamplesObjC/Base.lproj/Main.storyboard

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="13122.16" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" useSafeAreas="YES" colorMatched="YES" initialViewController="BYZ-38-t0r">
+    <dependencies>
+        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="13104.12"/>
+        <capability name="Safe area layout guides" minToolsVersion="9.0"/>
+        <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
+    </dependencies>
+    <scenes>
+        <!--View Controller-->
+        <scene sceneID="tne-QT-ifu">
+            <objects>
+                <viewController id="BYZ-38-t0r" customClass="ViewController" customModuleProvider="" sceneMemberID="viewController">
+                    <view key="view" contentMode="scaleToFill" id="8bC-Xf-vdC">
+                        <rect key="frame" x="0.0" y="0.0" width="375" height="667"/>
+                        <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
+                        <color key="backgroundColor" red="1" green="1" blue="1" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
+                        <viewLayoutGuide key="safeArea" id="6Tk-OE-BBY"/>
+                    </view>
+                </viewController>
+                <placeholder placeholderIdentifier="IBFirstResponder" id="dkx-z0-nzr" sceneMemberID="firstResponder"/>
+            </objects>
+        </scene>
+    </scenes>
+</document>

Examples/SamplesObjC/SamplesObjC/Info.plist

@@ -0,0 +1,45 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>CFBundleDevelopmentRegion</key>
+	<string>$(DEVELOPMENT_LANGUAGE)</string>
+	<key>CFBundleExecutable</key>
+	<string>$(EXECUTABLE_NAME)</string>
+	<key>CFBundleIdentifier</key>
+	<string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
+	<key>CFBundleInfoDictionaryVersion</key>
+	<string>6.0</string>
+	<key>CFBundleName</key>
+	<string>$(PRODUCT_NAME)</string>
+	<key>CFBundlePackageType</key>
+	<string>APPL</string>
+	<key>CFBundleShortVersionString</key>
+	<string>1.0</string>
+	<key>CFBundleVersion</key>
+	<string>1</string>
+	<key>LSRequiresIPhoneOS</key>
+	<true/>
+	<key>UILaunchStoryboardName</key>
+	<string>LaunchScreen</string>
+	<key>UIMainStoryboardFile</key>
+	<string>Main</string>
+	<key>UIRequiredDeviceCapabilities</key>
+	<array>
+		<string>armv7</string>
+	</array>
+	<key>UISupportedInterfaceOrientations</key>
+	<array>
+		<string>UIInterfaceOrientationPortrait</string>
+		<string>UIInterfaceOrientationLandscapeLeft</string>
+		<string>UIInterfaceOrientationLandscapeRight</string>
+	</array>
+	<key>UISupportedInterfaceOrientations~ipad</key>
+	<array>
+		<string>UIInterfaceOrientationPortrait</string>
+		<string>UIInterfaceOrientationPortraitUpsideDown</string>
+		<string>UIInterfaceOrientationLandscapeLeft</string>
+		<string>UIInterfaceOrientationLandscapeRight</string>
+	</array>
+</dict>
+</plist>

Examples/SamplesObjC/SamplesObjC/SamplesObjC-Bridging-Header.h

@@ -0,0 +1,3 @@
+//
+//  Use this file to import your target's public headers that you would like to expose to Swift.
+//

Examples/SamplesObjC/SamplesObjC/ViewController.h

@@ -0,0 +1,13 @@
+// Copyright 2018 the FloatingPanel authors. All rights reserved. MIT license.
+
+#import <UIKit/UIKit.h>
+@import FloatingPanel;
+
+@interface ViewController : UIViewController
+@end
+
+@interface MyFloatingPanelLayout : NSObject <FloatingPanelLayout>
+@end
+
+@interface MyFloatingPanelBehavior : NSObject <FloatingPanelBehavior>
+@end

Examples/SamplesObjC/SamplesObjC/ViewController.m

@@ -0,0 +1,97 @@
+// Copyright 2018 the FloatingPanel authors. All rights reserved. MIT license.
+
+#import "ViewController.h"
+@import FloatingPanel;
+
+// Defining a custom FloatingPanelState
+@interface FloatingPanelState(Extended)
++ (FloatingPanelState *)LastQuart;
+@end
+
+@implementation FloatingPanelState(Extended)
+static FloatingPanelState *_lastQuart;
++ (FloatingPanelState *)LastQuart {
+    static dispatch_once_t onceToken;
+    dispatch_once(&onceToken, ^{
+        _lastQuart = [[FloatingPanelState alloc] initWithRawValue:@"lastquart" order:750];
+    });
+    return _lastQuart;
+}
+@end
+
+@interface ViewController()<FloatingPanelControllerDelegate>
+@end
+
+@implementation ViewController
+
+- (void)viewDidLoad {
+    [super viewDidLoad];
+
+    FloatingPanelController *fpc = [[FloatingPanelController alloc] init];
+    [fpc setContentViewController:nil];
+    [fpc trackScrollView:nil];
+    [fpc setDelegate:self];
+
+    [fpc setLayout: [MyFloatingPanelLayout new]];
+    [fpc setBehavior:[MyFloatingPanelBehavior new]];
+    [fpc setRemovalInteractionEnabled:NO];
+
+    [fpc addPanelToParent:self at:self.view.subviews.count  animated:NO];
+    [fpc moveToState:FloatingPanelState.Tip animated:true completion:nil];
+
+    [self updateAppearance: fpc];
+}
+
+- (id<FloatingPanelLayout>)floatingPanel:(FloatingPanelController *)vc layoutFor:(UITraitCollection *)newCollection {
+    FloatingPanelBottomLayout *layout = [FloatingPanelBottomLayout new];
+    return layout;
+}
+
+- (void)updateAppearance: (FloatingPanelController*)fpc
+{
+    FloatingPanelSurfaceAppearance *appearance = [[FloatingPanelSurfaceAppearance alloc] init];
+    appearance.backgroundColor = [UIColor clearColor];
+    appearance.cornerRadius = 23.0;
+    if (@available(iOS 13.0, *)) {
+        fpc.surfaceView.containerView.layer.cornerCurve = kCACornerCurveContinuous;
+    }
+    FloatingPanelSurfaceAppearanceShadow *shadow = [[FloatingPanelSurfaceAppearanceShadow alloc] init];
+    shadow.color = [UIColor redColor];
+    shadow.radius = 10.0;
+    shadow.spread = 10.0;
+    FloatingPanelSurfaceAppearanceShadow *shadow2 = [[FloatingPanelSurfaceAppearanceShadow alloc] init];
+    shadow2.color = [UIColor blueColor];
+    shadow2.radius = 10.0;
+    shadow2.spread = 10.0;
+
+    appearance.shadows = @[shadow, shadow2];
+    fpc.surfaceView.appearance = appearance;
+}
+@end
+
+@implementation  MyFloatingPanelLayout
+- (FloatingPanelState *)initialState {
+    return FloatingPanelState.Half;
+}
+- (NSDictionary<FloatingPanelState *, id<FloatingPanelLayoutAnchoring>> *)anchors {
+    return @{
+        FloatingPanelState.LastQuart: [[FloatingPanelLayoutAnchor alloc] initWithFractionalInset:0.25
+                                                                                       edge:FloatingPanelReferenceEdgeTop
+                                                                             referenceGuide:FloatingPanelLayoutReferenceGuideSafeArea],
+        FloatingPanelState.Half: [[FloatingPanelLayoutAnchor alloc] initWithFractionalInset:0.5
+                                                                                       edge:FloatingPanelReferenceEdgeTop
+                                                                             referenceGuide:FloatingPanelLayoutReferenceGuideSafeArea],
+        FloatingPanelState.Tip: [[FloatingPanelLayoutAnchor alloc] initWithAbsoluteInset:44.0
+                                                                                    edge:FloatingPanelReferenceEdgeBottom
+                                                                          referenceGuide:FloatingPanelLayoutReferenceGuideSafeArea],
+    };
+}
+
+- (enum FloatingPanelPosition)position {
+    return FloatingPanelPositionBottom;
+}
+@end
+
+
+@implementation MyFloatingPanelBehavior
+@end

Examples/SamplesObjC/SamplesObjC/main.m

@@ -0,0 +1,10 @@
+// Copyright 2018 the FloatingPanel authors. All rights reserved. MIT license.
+
+#import <UIKit/UIKit.h>
+#import "AppDelegate.h"
+
+int main(int argc, char * argv[]) {
+    @autoreleasepool {
+        return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class]));
+    }
+}

Examples/Stocks/Stocks.xcodeproj/project.pbxproj

@@ -7,13 +7,13 @@
 	objects = {
 
 /* Begin PBXBuildFile section */
-		5433F24B21717EA300BDAA5D /* FloatingPanel.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 5433F24A21717EA300BDAA5D /* FloatingPanel.framework */; };
-		5433F24C21717EA300BDAA5D /* FloatingPanel.framework in Embed Frameworks */ = {isa = PBXBuildFile; fileRef = 5433F24A21717EA300BDAA5D /* FloatingPanel.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
 		548DF95421705BE00041922A /* AppDelegate.swift in Sources */ = {isa = PBXBuildFile; fileRef = 548DF95321705BE00041922A /* AppDelegate.swift */; };
 		548DF95621705BE00041922A /* ViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 548DF95521705BE00041922A /* ViewController.swift */; };
 		548DF95921705BE00041922A /* Main.storyboard in Resources */ = {isa = PBXBuildFile; fileRef = 548DF95721705BE00041922A /* Main.storyboard */; };
 		548DF95B21705BE10041922A /* Assets.xcassets in Resources */ = {isa = PBXBuildFile; fileRef = 548DF95A21705BE10041922A /* Assets.xcassets */; };
 		548DF95E21705BE10041922A /* LaunchScreen.storyboard in Resources */ = {isa = PBXBuildFile; fileRef = 548DF95C21705BE10041922A /* LaunchScreen.storyboard */; };
+		549D23CF233C77CF008EF4D7 /* FloatingPanel.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 549D23CE233C77CF008EF4D7 /* FloatingPanel.framework */; };
+		549D23D0233C77CF008EF4D7 /* FloatingPanel.framework in Embed Frameworks */ = {isa = PBXBuildFile; fileRef = 549D23CE233C77CF008EF4D7 /* FloatingPanel.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
 /* End PBXBuildFile section */
 
 /* Begin PBXCopyFilesBuildPhase section */
@@ -23,7 +23,7 @@
 			dstPath = "";
 			dstSubfolderSpec = 10;
 			files = (
-				5433F24C21717EA300BDAA5D /* FloatingPanel.framework in Embed Frameworks */,
+				549D23D0233C77CF008EF4D7 /* FloatingPanel.framework in Embed Frameworks */,
 			);
 			name = "Embed Frameworks";
 			runOnlyForDeploymentPostprocessing = 0;
@@ -31,7 +31,6 @@
 /* End PBXCopyFilesBuildPhase section */
 
 /* Begin PBXFileReference section */
-		5433F24A21717EA300BDAA5D /* FloatingPanel.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; path = FloatingPanel.framework; sourceTree = BUILT_PRODUCTS_DIR; };
 		548DF95021705BE00041922A /* Stocks.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = Stocks.app; sourceTree = BUILT_PRODUCTS_DIR; };
 		548DF95321705BE00041922A /* AppDelegate.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AppDelegate.swift; sourceTree = "<group>"; };
 		548DF95521705BE00041922A /* ViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ViewController.swift; sourceTree = "<group>"; };
@@ -39,6 +38,7 @@
 		548DF95A21705BE10041922A /* Assets.xcassets */ = {isa = PBXFileReference; lastKnownFileType = folder.assetcatalog; path = Assets.xcassets; sourceTree = "<group>"; };
 		548DF95D21705BE10041922A /* Base */ = {isa = PBXFileReference; lastKnownFileType = file.storyboard; name = Base; path = Base.lproj/LaunchScreen.storyboard; sourceTree = "<group>"; };
 		548DF95F21705BE10041922A /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
+		549D23CE233C77CF008EF4D7 /* FloatingPanel.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; path = FloatingPanel.framework; sourceTree = BUILT_PRODUCTS_DIR; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -46,7 +46,7 @@
 			isa = PBXFrameworksBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
-				5433F24B21717EA300BDAA5D /* FloatingPanel.framework in Frameworks */,
+				549D23CF233C77CF008EF4D7 /* FloatingPanel.framework in Frameworks */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -56,7 +56,7 @@
 		548DF94721705BE00041922A = {
 			isa = PBXGroup;
 			children = (
-				5433F24A21717EA300BDAA5D /* FloatingPanel.framework */,
+				549D23CE233C77CF008EF4D7 /* FloatingPanel.framework */,
 				548DF95221705BE00041922A /* Stocks */,
 				548DF95121705BE00041922A /* Products */,
 			);
@@ -312,7 +312,7 @@
 				);
 				PRODUCT_BUNDLE_IDENTIFIER = com.scenee.Stocks;
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 4.2;
+				SWIFT_VERSION = 5.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 			};
 			name = Debug;
@@ -331,7 +331,7 @@
 				);
 				PRODUCT_BUNDLE_IDENTIFIER = com.scenee.Stocks;
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 4.2;
+				SWIFT_VERSION = 5.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 			};
 			name = Release;

Examples/Stocks/Stocks/AppDelegate.swift

@@ -1,10 +1,4 @@
-//
-//  AppDelegate.swift
-//  Stocks
-//
-//  Created by Shin Yamamoto on 2018/10/12.
-//  Copyright © 2018 Shin Yamamoto. All rights reserved.
-//
+// Copyright 2018 the FloatingPanel authors. All rights reserved. MIT license.
 
 import UIKit
 

Examples/Stocks/Stocks/ViewController.swift

@@ -1,10 +1,4 @@
-//
-//  ViewController.swift
-//  Stocks
-//
-//  Created by Shin Yamamoto on 2018/10/12.
-//  Copyright © 2018 Shin Yamamoto. All rights reserved.
-//
+// Copyright 2018 the FloatingPanel authors. All rights reserved. MIT license.
 
 import UIKit
 import FloatingPanel
@@ -18,19 +12,21 @@ class ViewController: UIViewController, FloatingPanelControllerDelegate {
     var newsVC: NewsViewController!
 
     var initialColor: UIColor = .black
+
     override func viewDidLoad() {
         super.viewDidLoad()
         initialColor = view.backgroundColor!
         // Initialize FloatingPanelController
         fpc = FloatingPanelController()
         fpc.delegate = self
+        fpc.behavior = FloatingPanelStocksBehavior()
 
         // Initialize FloatingPanelController and add the view
         fpc.surfaceView.backgroundColor = UIColor(displayP3Red: 30.0/255.0, green: 30.0/255.0, blue: 30.0/255.0, alpha: 1.0)
-        fpc.surfaceView.cornerRadius = 24.0
-        fpc.surfaceView.shadowHidden = true
-        fpc.surfaceView.borderWidth = 1.0 / traitCollection.displayScale
-        fpc.surfaceView.borderColor = UIColor.black.withAlphaComponent(0.2)
+        fpc.surfaceView.appearance.cornerRadius = 24.0
+        fpc.surfaceView.appearance.shadows = []
+        fpc.surfaceView.appearance.borderWidth = 1.0 / traitCollection.displayScale
+        fpc.surfaceView.appearance.borderColor = UIColor.black.withAlphaComponent(0.2)
 
         newsVC = storyboard?.instantiateViewController(withIdentifier: "News") as? NewsViewController
 
@@ -38,7 +34,7 @@ class ViewController: UIViewController, FloatingPanelControllerDelegate {
         fpc.set(contentViewController: newsVC)
         fpc.track(scrollView: newsVC.scrollView)
 
-        fpc.addPanel(toParent: self, belowView: bottomToolView, animated: false)
+        fpc.addPanel(toParent: self, at: view.subviews.firstIndex(of: bottomToolView) ?? -1 , animated: false)
 
         topBannerView.frame = .zero
         topBannerView.alpha = 0.0
@@ -50,46 +46,46 @@ class ViewController: UIViewController, FloatingPanelControllerDelegate {
             ])
     }
 
-    override func viewDidAppear(_ animated: Bool) {
-        super.viewDidAppear(animated)
-    }
-
-    override func viewDidDisappear(_ animated: Bool) {
-        super.viewDidDisappear(animated)
-    }
-
     override var preferredStatusBarStyle: UIStatusBarStyle {
         return .lightContent
     }
 
     // MARK: FloatingPanelControllerDelegate
 
-    func floatingPanel(_ vc: FloatingPanelController, layoutFor newCollection: UITraitCollection) -> FloatingPanelLayout? {
+    func floatingPanel(_ vc: FloatingPanelController, layoutFor newCollection: UITraitCollection) -> FloatingPanelLayout {
         return FloatingPanelStocksLayout()
     }
 
-    func floatingPanel(_ vc: FloatingPanelController, behaviorFor newCollection: UITraitCollection) -> FloatingPanelBehavior? {
-        return FloatingPanelStocksBehavior()
-    }
+    func floatingPanelDidMove(_ vc: FloatingPanelController) {
+        if vc.isAttracting == false {
+            let loc = vc.surfaceLocation
+            let minY = vc.surfaceLocation(for: .full).y
+            let maxY = vc.surfaceLocation(for: .tip).y
+            vc.surfaceLocation = CGPoint(x: loc.x, y: min(max(loc.y, minY), maxY))
+        }
 
-    func floatingPanelWillBeginDragging(_ vc: FloatingPanelController) {
-        if vc.position == .full {
-            // Dimiss top bar with dissolve animation
-            UIView.animate(withDuration: 0.25) {
-                self.topBannerView.alpha = 0.0
-                self.labelStackView.alpha = 1.0
-                self.view.backgroundColor = self.initialColor
-            }
+        if vc.surfaceLocation.y <= vc.surfaceLocation(for: .full).y + 100 {
+            showStockTickerBanner()
+        } else {
+            hideStockTickerBanner()
         }
     }
-    func floatingPanelDidEndDragging(_ vc: FloatingPanelController, withVelocity velocity: CGPoint, targetPosition: FloatingPanelPosition) {
-        if targetPosition == .full {
-            // Present top bar with dissolve animation
-            UIView.animate(withDuration: 0.25) {
-                self.topBannerView.alpha = 1.0
-                self.labelStackView.alpha = 0.0
-                self.view.backgroundColor = .black
-            }
+
+    private func showStockTickerBanner() {
+        // Present top bar with dissolve animation
+        UIView.animate(withDuration: 0.25) {
+            self.topBannerView.alpha = 1.0
+            self.labelStackView.alpha = 0.0
+            self.view.backgroundColor = .black
+        }
+    }
+
+    private func hideStockTickerBanner() {
+        // Dimiss top bar with dissolve animation
+        UIView.animate(withDuration: 0.25) {
+            self.topBannerView.alpha = 0.0
+            self.labelStackView.alpha = 1.0
+            self.view.backgroundColor = .black
         }
     }
 }
@@ -99,57 +95,29 @@ class NewsViewController: UIViewController {
 }
 
 
-// MARK: My custom layout
+// MARK: - FloatingPanelLayout
 
 class FloatingPanelStocksLayout: FloatingPanelLayout {
-    var initialPosition: FloatingPanelPosition {
-        return .tip
+    let position: FloatingPanelPosition = .bottom
+    let initialState: FloatingPanelState = .tip
+
+    var anchors: [FloatingPanelState: FloatingPanelLayoutAnchoring] {
+        return [
+            .full: FloatingPanelLayoutAnchor(absoluteInset: 56.0, edge: .top, referenceGuide: .safeArea),
+            .half: FloatingPanelLayoutAnchor(absoluteInset: 262.0, edge: .bottom, referenceGuide: .safeArea),
+             /* Visible + ToolView */
+            .tip: FloatingPanelLayoutAnchor(absoluteInset: 85.0 + 44.0, edge: .bottom, referenceGuide: .safeArea),
+        ]
     }
 
-    var topInteractionBuffer: CGFloat { return 0.0 }
-    var bottomInteractionBuffer: CGFloat { return 0.0 }
-
-    func insetFor(position: FloatingPanelPosition) -> CGFloat? {
-        switch position {
-        case .full: return 56.0
-        case .half: return 262.0
-        case .tip: return 85.0 + 44.0 // Visible + ToolView
-        default: return nil
-        }
-    }
-
-    func backdropAlphaFor(position: FloatingPanelPosition) -> CGFloat {
+    func backdropAlpha(for state: FloatingPanelState) -> CGFloat {
         return 0.0
     }
 }
 
-// MARK: My custom behavior
+// MARK: - FloatingPanelBehavior
 
 class FloatingPanelStocksBehavior: FloatingPanelBehavior {
-    var velocityThreshold: CGFloat {
-        return 15.0
-    }
-
-    func interactionAnimator(_ fpc: FloatingPanelController, to targetPosition: FloatingPanelPosition, with velocity: CGVector) -> UIViewPropertyAnimator {
-        let timing = timeingCurve(to: targetPosition, with: velocity)
-        return UIViewPropertyAnimator(duration: 0, timingParameters: timing)
-    }
-
-    private func timeingCurve(to: FloatingPanelPosition, with velocity: CGVector) -> UITimingCurveProvider {
-        let damping = self.damping(with: velocity)
-        return UISpringTimingParameters(dampingRatio: damping,
-                                        frequencyResponse: 0.4,
-                                        initialVelocity: velocity)
-    }
-
-    private func damping(with velocity: CGVector) -> CGFloat {
-        switch velocity.dy {
-        case ...(-velocityThreshold):
-            return 0.7
-        case velocityThreshold...:
-            return 0.7
-        default:
-            return 1.0
-        }
-    }
+    let springDecelerationRate: CGFloat = UIScrollView.DecelerationRate.fast.rawValue
+    let springResponseTime: CGFloat = 0.25
 }

FloatingPanel.podspec

@@ -1,24 +1,22 @@
 Pod::Spec.new do |s|
 
   s.name                = "FloatingPanel"
-  s.version             = "1.3.1"
+  s.version             = "2.3.0"
   s.summary             = "FloatingPanel is a clean and easy-to-use UI component of a floating panel interface."
   s.description         = <<-DESC
 FloatingPanel is a clean and easy-to-use UI component for a new interface introduced in Apple Maps, Shortcuts and Stocks app.
 The new interface displays the related contents and utilities in parallel as a user wants.
                    DESC
   s.homepage            = "https://github.com/SCENEE/FloatingPanel"
-  # s.screenshots       = ""
+  s.author              = "Shin Yamamoto"
+  s.social_media_url    = "https://twitter.com/scenee"
 
   s.platform            = :ios, "10.0"
-  s.source              = { :git => "https://github.com/SCENEE/FloatingPanel.git", :tag => "v#{s.version}" }
-  s.source_files        = "Framework/Sources/*.swift"
-  s.swift_version       = "4.2"
-  s.pod_target_xcconfig = { 'SWIFT_WHOLE_MODULE_OPTIMIZATION' => 'YES', 'APPLICATION_EXTENSION_API_ONLY' => 'YES' }
+  s.source              = { :git => "https://github.com/SCENEE/FloatingPanel.git", :tag => s.version.to_s }
+  s.source_files        = "Sources/*.swift"
+  s.swift_versions      = ['5.1', '5.2', '5.3']
 
   s.framework           = "UIKit"
 
-  s.author              = { "Shin Yamamoto" => "shin@scenee.com" }
   s.license             = { :type => "MIT", :file => "LICENSE" }
-  s.social_media_url    = "https://twitter.com/scenee"
 end

FloatingPanel.xcodeproj/project.pbxproj

@@ -0,0 +1,819 @@
+// !$*UTF8*$!
+{
+	archiveVersion = 1;
+	classes = {
+	};
+	objectVersion = 50;
+	objects = {
+
+/* Begin PBXBuildFile section */
+		542753C622C49A6E00D17955 /* LayoutTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 542753C522C49A6E00D17955 /* LayoutTests.swift */; };
+		54352E9621A51A2500CBCA08 /* Transitioning.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54352E9521A51A2500CBCA08 /* Transitioning.swift */; };
+		54352E9821A521CA00CBCA08 /* PassthroughView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54352E9721A521CA00CBCA08 /* PassthroughView.swift */; };
+		5450EEE421646DF500135936 /* Behavior.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5450EEE321646DF500135936 /* Behavior.swift */; };
+		545DB9CB2151169500CA77B8 /* FloatingPanel.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 545DB9C12151169500CA77B8 /* FloatingPanel.framework */; };
+		545DB9D02151169500CA77B8 /* ControllerTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 545DB9CF2151169500CA77B8 /* ControllerTests.swift */; };
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+
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+			defaultConfigurationName = Release;
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+/* End XCConfigurationList section */
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+	rootObject = 545DB9B82151169500CA77B8 /* Project object */;
+}

FloatingPanel.xcodeproj/xcshareddata/IDETemplateMacros.plist

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>FILEHEADER</key>
+	<string> Copyright 2018 the FloatingPanel authors. All rights reserved. MIT license.</string>
+</dict>
+</plist>

FloatingPanel.xcodeproj/xcshareddata/xcschemes/FloatingPanel.xcscheme

@@ -23,12 +23,33 @@
       </BuildActionEntries>
    </BuildAction>
    <TestAction
-      buildConfiguration = "Debug"
+      buildConfiguration = "Test"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
       shouldUseLaunchSchemeArgsEnv = "YES">
       <Testables>
+         <TestableReference
+            skipped = "NO"
+            parallelizable = "YES"
+            testExecutionOrdering = "random">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "545DB9C92151169500CA77B8"
+               BuildableName = "FloatingPanelTests.xctest"
+               BlueprintName = "FloatingPanelTests"
+               ReferencedContainer = "container:FloatingPanel.xcodeproj">
+            </BuildableReference>
+         </TestableReference>
       </Testables>
+      <MacroExpansion>
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "545DB9C02151169500CA77B8"
+            BuildableName = "FloatingPanel.framework"
+            BlueprintName = "FloatingPanel"
+            ReferencedContainer = "container:FloatingPanel.xcodeproj">
+         </BuildableReference>
+      </MacroExpansion>
       <AdditionalOptions>
       </AdditionalOptions>
    </TestAction>

FloatingPanel.xcworkspace/contents.xcworkspacedata

@@ -4,13 +4,9 @@
    <FileRef
       location = "group:README.md">
    </FileRef>
-   <Group
-      location = "group:Framework"
-      name = "Framework">
-      <FileRef
-         location = "group:FloatingPanel.xcodeproj">
-      </FileRef>
-   </Group>
+   <FileRef
+      location = "group:FloatingPanel.xcodeproj">
+   </FileRef>
    <Group
       location = "group:Examples"
       name = "Examples">
@@ -23,5 +19,8 @@
       <FileRef
          location = "group:Samples/Samples.xcodeproj">
       </FileRef>
+      <FileRef
+         location = "group:SamplesObjC/SamplesObjC.xcodeproj">
+      </FileRef>
    </Group>
 </Workspace>

Framework/FloatingPanel.xcodeproj/project.pbxproj

@@ -1,509 +0,0 @@
-// !$*UTF8*$!
-{
-	archiveVersion = 1;
-	classes = {
-	};
-	objectVersion = 50;
-	objects = {
-
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-		5450EEE421646DF500135936 /* FloatingPanelBehavior.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5450EEE321646DF500135936 /* FloatingPanelBehavior.swift */; };
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-		545DB9DA2151169500CA77B8 /* Release */ = {
-			isa = XCBuildConfiguration;
-			buildSettings = {
-				ALWAYS_EMBED_SWIFT_STANDARD_LIBRARIES = YES;
-				CODE_SIGN_STYLE = Automatic;
-				INFOPLIST_FILE = Tests/Info.plist;
-				LD_RUNPATH_SEARCH_PATHS = (
-					"$(inherited)",
-					"@executable_path/Frameworks",
-					"@loader_path/Frameworks",
-				);
-				PRODUCT_BUNDLE_IDENTIFIER = com.scenee.FloatingModalControllerTests;
-				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 4.2;
-				TARGETED_DEVICE_FAMILY = "1,2";
-			};
-			name = Release;
-		};
-/* End XCBuildConfiguration section */
-
-/* Begin XCConfigurationList section */
-		545DB9BB2151169500CA77B8 /* Build configuration list for PBXProject "FloatingPanel" */ = {
-			isa = XCConfigurationList;
-			buildConfigurations = (
-				545DB9D32151169500CA77B8 /* Debug */,
-				545DB9D42151169500CA77B8 /* Release */,
-			);
-			defaultConfigurationIsVisible = 0;
-			defaultConfigurationName = Release;
-		};
-		545DB9D52151169500CA77B8 /* Build configuration list for PBXNativeTarget "FloatingPanel" */ = {
-			isa = XCConfigurationList;
-			buildConfigurations = (
-				545DB9D62151169500CA77B8 /* Debug */,
-				545DB9D72151169500CA77B8 /* Release */,
-			);
-			defaultConfigurationIsVisible = 0;
-			defaultConfigurationName = Release;
-		};
-		545DB9D82151169500CA77B8 /* Build configuration list for PBXNativeTarget "FloatingPanelTests" */ = {
-			isa = XCConfigurationList;
-			buildConfigurations = (
-				545DB9D92151169500CA77B8 /* Debug */,
-				545DB9DA2151169500CA77B8 /* Release */,
-			);
-			defaultConfigurationIsVisible = 0;
-			defaultConfigurationName = Release;
-		};
-/* End XCConfigurationList section */
-	};
-	rootObject = 545DB9B82151169500CA77B8 /* Project object */;
-}

Framework/Sources/FloatingPanel.swift

@@ -1,805 +0,0 @@
-//
-//  Copyright © 2018 Shin Yamamoto. All rights reserved.
-//
-
-import UIKit
-
-///
-/// FloatingPanel presentation model
-///
-class FloatingPanel: NSObject, UIGestureRecognizerDelegate, UIScrollViewDelegate {
-    // MUST be a weak reference to prevent UI freeze on the presentaion modally
-    weak var viewcontroller: FloatingPanelController!
-
-    let surfaceView: FloatingPanelSurfaceView
-    let backdropView: FloatingPanelBackdropView
-    var layoutAdapter: FloatingPanelLayoutAdapter
-    var behavior: FloatingPanelBehavior
-
-    weak var scrollView: UIScrollView? {
-        didSet {
-            guard let scrollView = scrollView else { return }
-            scrollView.panGestureRecognizer.addTarget(self, action: #selector(handle(panGesture:)))
-            scrollBouncable = scrollView.bounces
-            scrollIndictorVisible = scrollView.showsVerticalScrollIndicator
-        }
-    }
-    weak var userScrollViewDelegate: UIScrollViewDelegate?
-
-    private(set) var state: FloatingPanelPosition = .hidden {
-        didSet { viewcontroller.delegate?.floatingPanelDidChangePosition(viewcontroller) }
-    }
-
-    private var isBottomState: Bool {
-        let remains = layoutAdapter.supportedPositions.filter { $0.rawValue > state.rawValue }
-        return remains.count == 0
-    }
-
-    let panGesture: FloatingPanelPanGestureRecognizer
-    var isRemovalInteractionEnabled: Bool = false
-
-    private var animator: UIViewPropertyAnimator?
-    private var initialFrame: CGRect = .zero
-    private var initialScrollOffset: CGPoint = .zero
-    private var transOffsetY: CGFloat = 0
-
-    var interactionInProgress: Bool = false
-
-    // Scroll handling
-    private var stopScrollDeceleration: Bool = false
-    private var scrollBouncable = false
-    private var scrollIndictorVisible = false
-
-    // MARK: - Interface
-
-    init(_ vc: FloatingPanelController, layout: FloatingPanelLayout, behavior: FloatingPanelBehavior) {
-        viewcontroller = vc
-
-        surfaceView = FloatingPanelSurfaceView()
-        surfaceView.backgroundColor = .white
-
-        backdropView = FloatingPanelBackdropView()
-        backdropView.backgroundColor = .black
-        backdropView.alpha = 0.0
-
-        self.layoutAdapter = FloatingPanelLayoutAdapter(surfaceView: surfaceView,
-                                                        backdropView: backdropView,
-                                                        layout: layout)
-        self.behavior = behavior
-
-        panGesture = FloatingPanelPanGestureRecognizer()
-
-        if #available(iOS 11.0, *) {
-            panGesture.name = "FloatingPanelSurface"
-        }
-
-        super.init()
-
-        surfaceView.addGestureRecognizer(panGesture)
-        panGesture.addTarget(self, action: #selector(handle(panGesture:)))
-        panGesture.delegate = self
-    }
-
-    func move(to: FloatingPanelPosition, animated: Bool, completion: (() -> Void)? = nil) {
-        move(from: state, to: to, animated: animated, completion: completion)
-    }
-
-    private func move(from: FloatingPanelPosition, to: FloatingPanelPosition, animated: Bool, completion: (() -> Void)? = nil) {
-        if to != .full {
-            lockScrollView()
-        }
-
-        if animated {
-            let animator: UIViewPropertyAnimator
-            switch (from, to) {
-            case (.hidden, let to):
-                animator = behavior.addAnimator(self.viewcontroller, to: to)
-            case (let from, .hidden):
-                animator = behavior.removeAnimator(self.viewcontroller, from: from)
-            case (let from, let to):
-                animator = behavior.moveAnimator(self.viewcontroller, from: from, to: to)
-            }
-
-            animator.addAnimations { [weak self] in
-                guard let self = self else { return }
-
-                self.updateLayout(to: to)
-                self.state = to
-            }
-            animator.addCompletion { _ in
-                completion?()
-            }
-            animator.startAnimation()
-        } else {
-            self.updateLayout(to: to)
-            self.state = to
-            completion?()
-        }
-    }
-
-    // MARK: - Layout update
-
-    private func updateLayout(to target: FloatingPanelPosition) {
-        self.layoutAdapter.activateLayout(of: target)
-    }
-
-    private func getBackdropAlpha(with translation: CGPoint) -> CGFloat {
-        let currentY = getCurrentY(from: initialFrame, with: translation)
-
-        let next = directionalPosition(with: translation)
-        let pre = redirectionalPosition(with: translation)
-        let nextY = layoutAdapter.positionY(for: next)
-        let preY = layoutAdapter.positionY(for: pre)
-
-        let nextAlpha = layoutAdapter.layout.backdropAlphaFor(position: next)
-        let preAlpha = layoutAdapter.layout.backdropAlphaFor(position: pre)
-
-        if preY == nextY {
-            return preAlpha
-        } else {
-            return preAlpha + max(min(1.0, 1.0 - (nextY - currentY) / (nextY - preY) ), 0.0) * (nextAlpha - preAlpha)
-        }
-    }
-
-    // MARK: - UIGestureRecognizerDelegate
-
-    public func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer,
-                                  shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
-        guard gestureRecognizer == panGesture else { return false }
-
-        /* log.debug("shouldRecognizeSimultaneouslyWith", otherGestureRecognizer) */
-
-        if viewcontroller.delegate?.floatingPanel(viewcontroller, shouldRecognizeSimultaneouslyWith: otherGestureRecognizer) ?? false {
-            return true
-        }
-
-        // all gestures of the tracking scroll view should be recognized in parallel
-        // and handle them in self.handle(panGesture:)
-        return scrollView?.gestureRecognizers?.contains(otherGestureRecognizer) ?? false
-    }
-
-    public func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldBeRequiredToFailBy otherGestureRecognizer: UIGestureRecognizer) -> Bool {
-        guard gestureRecognizer == panGesture else { return false }
-        /* log.debug("shouldBeRequiredToFailBy", otherGestureRecognizer) */
-        return false
-    }
-
-    public func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRequireFailureOf otherGestureRecognizer: UIGestureRecognizer) -> Bool {
-        guard gestureRecognizer == panGesture else { return false }
-
-        /* log.debug("shouldRequireFailureOf", otherGestureRecognizer) */
-
-        // Should begin the pan gesture without waiting for the tracking scroll view's gestures.
-        // `scrollView.gestureRecognizers` can contains the following gestures
-        // * UIScrollViewDelayedTouchesBeganGestureRecognizer
-        // * UIScrollViewPanGestureRecognizer (scrollView.panGestureRecognizer)
-        // * _UIDragAutoScrollGestureRecognizer
-        // * _UISwipeActionPanGestureRecognizer
-        // * UISwipeDismissalGestureRecognizer
-        if let scrollView = scrollView {
-            // On short contents scroll, `_UISwipeActionPanGestureRecognizer` blocks
-            // the panel's pan gesture if not returns false
-            if let scrollGestureRecognizers = scrollView.gestureRecognizers,
-                scrollGestureRecognizers.contains(otherGestureRecognizer) {
-                return false
-            }
-        }
-
-        if viewcontroller.delegate?.floatingPanel(viewcontroller, shouldRecognizeSimultaneouslyWith: otherGestureRecognizer) ?? false {
-            return false
-        }
-
-
-        switch otherGestureRecognizer {
-        case is UIPanGestureRecognizer,
-             is UISwipeGestureRecognizer,
-             is UIRotationGestureRecognizer,
-             is UIScreenEdgePanGestureRecognizer,
-             is UIPinchGestureRecognizer:
-            // Do not begin the pan gesture until these gestures fail
-            return true
-        default:
-            // Should begin the pan gesture witout waiting tap/long press gestures fail
-            return false
-        }
-    }
-
-    var grabberAreaFrame: CGRect {
-        let grabberAreaFrame = CGRect(x: surfaceView.bounds.origin.x,
-                                     y: surfaceView.bounds.origin.y,
-                                     width: surfaceView.bounds.width,
-                                     height: FloatingPanelSurfaceView.topGrabberBarHeight * 2)
-        return grabberAreaFrame
-    }
-
-    // MARK: - Gesture handling
-    private let offsetThreshold: CGFloat = 5.0 // Optimal value from testing
-    @objc func handle(panGesture: UIPanGestureRecognizer) {
-        log.debug("Gesture >>>>", panGesture)
-        let velocity = panGesture.velocity(in: panGesture.view)
-
-        switch panGesture {
-        case scrollView?.panGestureRecognizer:
-            guard let scrollView = scrollView else { return }
-
-            log.debug("SrollPanGesture ScrollView.contentOffset >>>", scrollView.contentOffset.y, scrollView.contentSize, scrollView.bounds.size)
-
-            // Prevent scoll slip by the top bounce when the scroll view's height is
-            // less than the content's height
-            if scrollView.isDecelerating == false, scrollView.contentSize.height > scrollView.bounds.height {
-                scrollView.bounces = (scrollView.contentOffset.y > offsetThreshold)
-            }
-
-            if surfaceView.frame.minY > layoutAdapter.topY {
-                switch state {
-                case .full:
-                    let point = panGesture.location(in: surfaceView)
-                    if grabberAreaFrame.contains(point) {
-                        // Preserve the current content offset in moving from full.
-                        scrollView.contentOffset.y = initialScrollOffset.y
-                    } else {
-                        // Prevent over scrolling in moving from full.
-                        scrollView.contentOffset.y = scrollView.contentOffsetZero.y
-                    }
-                case .half, .tip:
-                    guard scrollView.isDecelerating == false else {
-                        // Don't fix the scroll offset in animating the panel to half and tip.
-                        // It causes a buggy scrolling deceleration because `state` becomes
-                        // a target position in animating the panel on the interaction from full.
-                        return
-                    }
-                    // Fix the scroll offset in moving the panel from half and tip.
-                    scrollView.contentOffset.y = initialScrollOffset.y
-                case .hidden:
-                    fatalError("A floating panel hidden must not be used by a user")
-                }
-
-                // Always hide a scroll indicator at the non-top.
-                if interactionInProgress {
-                    lockScrollView()
-                }
-            } else {
-                // Always show a scroll indicator at the top.
-                if interactionInProgress {
-                    unlockScrollView()
-                }
-            }
-        case panGesture:
-            let translation = panGesture.translation(in: panGesture.view!.superview)
-            let location = panGesture.location(in: panGesture.view)
-
-            log.debug(panGesture.state, ">>>", "translation: \(translation.y), velocity: \(velocity.y)")
-
-            if shouldScrollViewHandleTouch(scrollView, point: location, velocity: velocity) {
-                return
-            }
-
-            if let animator = self.animator, animator.isInterruptible {
-                animator.stopAnimation(true)
-                self.animator = nil
-            }
-
-            switch panGesture.state {
-            case .began:
-                panningBegan()
-            case .changed:
-                if interactionInProgress == false {
-                    startInteraction(with: translation)
-                }
-                panningChange(with: translation)
-            case .ended, .cancelled, .failed:
-                panningEnd(with: translation, velocity: velocity)
-            case .possible:
-                break
-            }
-        default:
-            return
-        }
-    }
-
-    private func shouldScrollViewHandleTouch(_ scrollView: UIScrollView?, point: CGPoint, velocity: CGPoint) -> Bool {
-        // When no scrollView, nothing to handle.
-        guard let scrollView = scrollView else { return false }
-
-        // For _UISwipeActionPanGestureRecognizer
-        if let scrollGestureRecognizers = scrollView.gestureRecognizers {
-            for gesture in scrollGestureRecognizers {
-                guard gesture.state == .began || gesture.state == .changed
-                else { continue }
-
-                if gesture !=  scrollView.panGestureRecognizer {
-                    return true
-                }
-            }
-        }
-
-        guard
-            state == .full,                   // When not .full, don't scroll.
-            interactionInProgress == false,   // When interaction already in progress, don't scroll.
-            scrollView.frame.contains(point), // When point not in scrollView, don't scroll.
-            !grabberAreaFrame.contains(point) // When point within grabber area, don't scroll.
-        else {
-            return false
-        }
-
-        log.debug("ScrollView.contentOffset >>>", scrollView.contentOffset.y)
-
-        let offset = scrollView.contentOffset.y - scrollView.contentOffsetZero.y
-        if  abs(offset) > offsetThreshold {
-            return true
-        }
-        if scrollView.isDecelerating {
-            return true
-        }
-        if velocity.y < 0 {
-            return true
-        }
-
-        return false
-    }
-
-    private func panningBegan() {
-        // A user interaction does not always start from Began state of the pan gesture
-        // because it can be recognized in scrolling a content in a content view controller.
-        // So do nothing here.
-        log.debug("panningBegan")
-    }
-
-    private func panningChange(with translation: CGPoint) {
-        log.debug("panningChange")
-
-        let currentY = getCurrentY(from: initialFrame, with: translation)
-
-        var frame = initialFrame
-        frame.origin.y = currentY
-        surfaceView.frame = frame
-        backdropView.alpha = getBackdropAlpha(with: translation)
-
-        viewcontroller.delegate?.floatingPanelDidMove(viewcontroller)
-    }
-
-    private func panningEnd(with translation: CGPoint, velocity: CGPoint) {
-        log.debug("panningEnd")
-        if interactionInProgress == false {
-            initialFrame = surfaceView.frame
-        }
-
-        stopScrollDeceleration = (surfaceView.frame.minY > layoutAdapter.topY) // Projecting the dragging to the scroll dragging or not
-
-        let targetPosition = self.targetPosition(with: translation, velocity: velocity)
-        let distance = self.distance(to: targetPosition, with: translation)
-
-        endInteraction(for: targetPosition)
-
-        if isRemovalInteractionEnabled, isBottomState {
-            let velocityVector = (distance != 0) ? CGVector(dx: 0,
-                                                            dy: max(min(velocity.y/distance, behavior.removalVelocity), 0.0)) : .zero
-
-
-
-            if shouldStartRemovalAnimation(with: translation, velocityVector: velocityVector) {
-
-                viewcontroller.delegate?.floatingPanelDidEndDraggingToRemove(viewcontroller, withVelocity: velocity)
-                self.startRemovalAnimation(with: velocityVector) { [weak self] in
-                    guard let self = self else { return }
-                    self.viewcontroller.dismiss(animated: false, completion: { [weak self] in
-                        guard let self = self else { return }
-                        self.viewcontroller.delegate?.floatingPanelDidEndRemove(self.viewcontroller)
-                    })
-                }
-                return
-            }
-        }
-
-        viewcontroller.delegate?.floatingPanelDidEndDragging(viewcontroller, withVelocity: velocity, targetPosition: targetPosition)
-        viewcontroller.delegate?.floatingPanelWillBeginDecelerating(viewcontroller)
-
-        startAnimation(to: targetPosition, at: distance, with: velocity)
-    }
-
-    private func shouldStartRemovalAnimation(with translation: CGPoint, velocityVector: CGVector) -> Bool {
-        let posY = layoutAdapter.positionY(for: state)
-        let currentY = getCurrentY(from: initialFrame, with: translation)
-        let safeAreaBottomY = layoutAdapter.safeAreaBottomY
-        let vth = behavior.removalVelocity
-        let pth = max(min(behavior.removalProgress, 1.0), 0.0)
-
-        let num = (currentY - posY)
-        let den = (safeAreaBottomY - posY)
-
-        guard num >= 0, den != 0, (num / den >= pth || velocityVector.dy == vth)
-        else { return false }
-
-        return true
-    }
-
-    private func startRemovalAnimation(with velocityVector: CGVector, completion: (() -> Void)?) {
-        let animator = self.behavior.removalInteractionAnimator(self.viewcontroller, with: velocityVector)
-
-        animator.addAnimations { [weak self] in
-            self?.updateLayout(to: .hidden)
-        }
-        animator.addCompletion({ _ in
-            completion?()
-        })
-        animator.startAnimation()
-    }
-
-    private func startInteraction(with translation: CGPoint) {
-        /* Don't lock a scroll view to show a scroll indicator after hitting the top */
-        log.debug("startInteraction")
-        initialFrame = surfaceView.frame
-        if let scrollView = scrollView {
-            initialScrollOffset = scrollView.contentOffset
-        }
-        transOffsetY = translation.y
-
-        viewcontroller.delegate?.floatingPanelWillBeginDragging(viewcontroller)
-
-        viewcontroller.contentViewController?.view?.constraints.forEach({ (const) in
-            switch viewcontroller.contentViewController?.layoutGuide.bottomAnchor {
-            case const.firstAnchor:
-                (const.secondItem as? UIView)?.disableAutoLayout()
-            case const.secondAnchor:
-                (const.firstItem as? UIView)?.disableAutoLayout()
-            default:
-                break
-            }
-        })
-
-        interactionInProgress = true
-    }
-
-    private func endInteraction(for targetPosition: FloatingPanelPosition) {
-        log.debug("endInteraction for \(targetPosition)")
-        interactionInProgress = false
-
-        // Prevent to keep a scoll view indicator visible at the half/tip position
-        if targetPosition != .full {
-            lockScrollView()
-        }
-
-        viewcontroller.contentViewController?.view?.constraints.forEach({ (const) in
-            switch viewcontroller.contentViewController?.layoutGuide.bottomAnchor {
-            case const.firstAnchor:
-                (const.secondItem as? UIView)?.enableAutoLayout()
-            case const.secondAnchor:
-                (const.firstItem as? UIView)?.enableAutoLayout()
-            default:
-                break
-            }
-        })
-    }
-
-    private func getCurrentY(from rect: CGRect, with translation: CGPoint) -> CGFloat {
-        let dy = translation.y - transOffsetY
-        let y = rect.offsetBy(dx: 0.0, dy: dy).origin.y
-
-        let topY = layoutAdapter.topY
-        let topBuffer = layoutAdapter.layout.topInteractionBuffer
-        let bottomY = layoutAdapter.bottomY
-        let bottomBuffer = layoutAdapter.layout.bottomInteractionBuffer
-
-        if let scrollView = scrollView, scrollView.panGestureRecognizer.state == .changed {
-            let preY = surfaceView.frame.origin.y
-            if preY > 0 && preY > y {
-                return max(topY, min(bottomY, y))
-            }
-        }
-        let topMax = layoutAdapter.topMaxY
-        let bottomMax = layoutAdapter.bottomMaxY
-        return max(max(topY - topBuffer, topMax), min(min(bottomY + bottomBuffer, bottomMax), y))
-    }
-
-    private func startAnimation(to targetPosition: FloatingPanelPosition, at distance: CGFloat, with velocity: CGPoint) {
-        log.debug("startAnimation", targetPosition, distance, velocity)
-        let targetY = layoutAdapter.positionY(for: targetPosition)
-        let velocityVector = (distance != 0) ? CGVector(dx: 0, dy: max(min(velocity.y/distance, 30.0), -30.0)) : .zero
-        let animator = behavior.interactionAnimator(self.viewcontroller, to: targetPosition, with: velocityVector)
-        animator.addAnimations { [weak self] in
-            guard let self = self else { return }
-            if self.state == targetPosition {
-                self.surfaceView.frame.origin.y = targetY
-                self.layoutAdapter.setBackdropAlpha(of: targetPosition)
-            } else {
-                self.updateLayout(to: targetPosition)
-            }
-            self.state = targetPosition
-        }
-        animator.addCompletion { [weak self] pos in
-            guard let self = self else { return }
-            guard
-                self.interactionInProgress == false,
-                animator == self.animator,
-                pos == .end
-                else { return }
-            self.finishAnimation(at: targetPosition)
-        }
-        animator.startAnimation()
-        self.animator = animator
-    }
-
-    private func finishAnimation(at targetPosition: FloatingPanelPosition) {
-        log.debug("finishAnimation \(targetPosition)")
-        self.animator = nil
-        self.viewcontroller.delegate?.floatingPanelDidEndDecelerating(self.viewcontroller)
-
-        stopScrollDeceleration = false
-        // Don't unlock scroll view in animating view when presentation layer != model layer
-        if targetPosition == .full {
-            unlockScrollView()
-        }
-    }
-
-    private func distance(to targetPosition: FloatingPanelPosition, with translation: CGPoint) -> CGFloat {
-        let topY = layoutAdapter.topY
-        let middleY = layoutAdapter.middleY
-        let bottomY = layoutAdapter.bottomY
-        let currentY = getCurrentY(from: initialFrame, with: translation)
-
-        switch targetPosition {
-        case .full:
-            return CGFloat(fabs(Double(currentY - topY)))
-        case .half:
-            return CGFloat(fabs(Double(currentY - middleY)))
-        case .tip:
-            return CGFloat(fabs(Double(currentY - bottomY)))
-        case .hidden:
-            fatalError("A floating panel hidden must not be used by a user")
-        }
-    }
-
-    private func directionalPosition(with translation: CGPoint) -> FloatingPanelPosition {
-        let currentY = getCurrentY(from: initialFrame, with: translation)
-
-        let supportedPositions = layoutAdapter.supportedPositions
-
-        if supportedPositions.count == 1 {
-            return state
-        }
-
-        switch supportedPositions {
-        case [.full, .half]: return translation.y >= 0 ? .half : .full
-        case [.half, .tip]: return translation.y >= 0 ? .tip : .half
-        case [.full, .tip]: return translation.y >= 0 ? .tip : .full
-        default:
-            let middleY = layoutAdapter.middleY
-
-            switch state {
-            case .full:
-                if translation.y <= 0 {
-                    return .full
-                }
-                return currentY > middleY ? .tip : .half
-            case .half:
-                return currentY > middleY ? .tip : .full
-            case .tip:
-                if translation.y >= 0 {
-                    return .tip
-                }
-                return currentY > middleY ? .half : .full
-            case .hidden:
-                fatalError("A floating panel hidden must not be used by a user")
-            }
-        }
-    }
-
-    private func redirectionalPosition(with translation: CGPoint) -> FloatingPanelPosition {
-        let currentY = getCurrentY(from: initialFrame, with: translation)
-
-        let supportedPositions = layoutAdapter.supportedPositions
-
-        if supportedPositions.count == 1 {
-            return state
-        }
-
-        switch supportedPositions {
-        case [.full, .half]: return translation.y >= 0 ? .full : .half
-        case [.half, .tip]: return translation.y >= 0 ? .half : .tip
-        case [.full, .tip]: return translation.y >= 0 ? .full : .tip
-        default:
-            let middleY = layoutAdapter.middleY
-
-            switch state {
-            case .full:
-                return currentY > middleY ? .half : .full
-            case .half:
-                return .half
-            case .tip:
-                return currentY > middleY ? .tip : .half
-            case .hidden:
-                fatalError("A floating panel hidden must not be used by a user")
-            }
-        }
-    }
-
-    // Distance travelled after decelerating to zero velocity at a constant rate.
-    // Refer to the slides p176 of [Designing Fluid Interfaces](https://developer.apple.com/videos/play/wwdc2018/803/)
-    private func project(initialVelocity: CGFloat) -> CGFloat {
-        let decelerationRate = UIScrollView.DecelerationRate.normal.rawValue
-        return (initialVelocity / 1000.0) * decelerationRate / (1.0 - decelerationRate)
-    }
-
-    private func targetPosition(with translation: CGPoint, velocity: CGPoint) -> (FloatingPanelPosition) {
-        let currentY = getCurrentY(from: initialFrame, with: translation)
-        let supportedPositions = layoutAdapter.supportedPositions
-
-        if supportedPositions.count == 1 {
-            return state
-        }
-
-        switch supportedPositions {
-        case [.full, .half]:
-            return targetPosition(from: [.full, .half], at: currentY, velocity: velocity)
-        case [.half, .tip]:
-            return targetPosition(from: [.half, .tip], at: currentY, velocity: velocity)
-        case [.full, .tip]:
-            return targetPosition(from: [.full, .tip], at: currentY, velocity: velocity)
-        default:
-            /*
-             [topY|full]---[th1]---[middleY|half]---[th2]---[bottomY|tip]
-             */
-            let topY = layoutAdapter.topY
-            let middleY = layoutAdapter.middleY
-            let bottomY = layoutAdapter.bottomY
-
-            let target: FloatingPanelPosition
-            let forwardYDirection: Bool
-
-            switch state {
-            case .full:
-                target = .half
-                forwardYDirection = true
-            case .half:
-                if (currentY < middleY) {
-                    target = .full
-                    forwardYDirection = false
-                } else {
-                    target = .tip
-                    forwardYDirection = true
-                }
-            case .tip:
-                target = .half
-                forwardYDirection = false
-            case .hidden:
-                fatalError("A floating panel hidden must not be used by a user")
-            }
-
-            let redirectionalProgress = max(min(behavior.redirectionalProgress(viewcontroller, from: state, to: target), 1.0), 0.0)
-
-            let th1: CGFloat
-            let th2: CGFloat
-
-            if forwardYDirection {
-                th1 = topY + (middleY - topY) * redirectionalProgress
-                th2 = middleY + (bottomY - middleY) * redirectionalProgress
-            } else {
-                th1 = middleY - (middleY - topY) * redirectionalProgress
-                th2 = bottomY - (bottomY - middleY) * redirectionalProgress
-            }
-
-            switch currentY {
-            case ..<th1:
-                if project(initialVelocity: velocity.y) >= (middleY - currentY) {
-                    return .half
-                } else {
-                    return .full
-                }
-            case ...middleY:
-                if project(initialVelocity: velocity.y) <= (topY - currentY) {
-                    return .full
-                } else {
-                    return .half
-                }
-            case ..<th2:
-                if project(initialVelocity: velocity.y) >= (bottomY - currentY) {
-                    return .tip
-                } else {
-                    return .half
-                }
-            default:
-                if project(initialVelocity: velocity.y) <= (middleY - currentY) {
-                    return .half
-                } else {
-                    return .tip
-                }
-            }
-        }
-    }
-
-    private func targetPosition(from positions: [FloatingPanelPosition], at currentY: CGFloat, velocity: CGPoint) -> FloatingPanelPosition {
-        assert(positions.count == 2)
-
-        let top = positions[0]
-        let bottom = positions[1]
-
-        let topY = layoutAdapter.positionY(for: top)
-        let bottomY = layoutAdapter.positionY(for: bottom)
-
-        let target = top == state ? bottom : top
-        let redirectionalProgress = max(min(behavior.redirectionalProgress(viewcontroller, from: state, to: target), 1.0), 0.0)
-
-        let th = topY + (bottomY - topY) * redirectionalProgress
-
-        switch currentY {
-        case ..<th:
-            if project(initialVelocity: velocity.y) >= (bottomY - currentY) {
-                return bottom
-            } else {
-                return top
-            }
-        default:
-            if project(initialVelocity: velocity.y) <= (topY - currentY) {
-                return top
-            } else {
-                return bottom
-            }
-        }
-    }
-
-    // MARK: - ScrollView handling
-
-    private func lockScrollView() {
-        guard let scrollView = scrollView else { return }
-
-        scrollView.isDirectionalLockEnabled = true
-        scrollView.bounces = false
-        scrollView.showsVerticalScrollIndicator = false
-    }
-
-    private func unlockScrollView() {
-        guard let scrollView = scrollView else { return }
-
-        scrollView.isDirectionalLockEnabled = false
-        scrollView.bounces = scrollBouncable
-        scrollView.showsVerticalScrollIndicator = scrollIndictorVisible
-    }
-
-
-    // MARK: - UIScrollViewDelegate Intermediation
-    override func responds(to aSelector: Selector!) -> Bool {
-        return super.responds(to: aSelector) || userScrollViewDelegate?.responds(to: aSelector) == true
-    }
-
-    override func forwardingTarget(for aSelector: Selector!) -> Any? {
-        if userScrollViewDelegate?.responds(to: aSelector) == true {
-            return userScrollViewDelegate
-        } else {
-            return super.forwardingTarget(for: aSelector)
-        }
-    }
-
-    func scrollViewDidEndScrollingAnimation(_ scrollView: UIScrollView) {
-        if state != .full {
-            initialScrollOffset = scrollView.contentOffset
-        }
-        userScrollViewDelegate?.scrollViewDidEndScrollingAnimation?(scrollView)
-    }
-
-    func scrollViewWillEndDragging(_ scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer<CGPoint>) {
-        if stopScrollDeceleration {
-            targetContentOffset.pointee = scrollView.contentOffset
-            stopScrollDeceleration = false
-        } else {
-            userScrollViewDelegate?.scrollViewWillEndDragging?(scrollView, withVelocity: velocity, targetContentOffset: targetContentOffset)
-        }
-    }
-}
-
-class FloatingPanelPanGestureRecognizer: UIPanGestureRecognizer {
-    override weak var delegate: UIGestureRecognizerDelegate? {
-        get {
-            return super.delegate
-        }
-        set {
-            guard newValue is FloatingPanel else {
-                let exception = NSException(name: .invalidArgumentException,
-                                            reason: "FloatingPanelController's built-in pan gesture recognizer must have its controller as its delegate.",
-                                            userInfo: nil)
-                exception.raise()
-                return
-            }
-            super.delegate = newValue
-        }
-    }
-}

Framework/Sources/FloatingPanelBackdropView.swift

@@ -1,9 +0,0 @@
-//
-//  Created by Shin Yamamoto on 2018/09/26.
-//  Copyright © 2018 Shin Yamamoto. All rights reserved.
-//
-
-import UIKit
-
-/// A view that presents a backdrop interface behind a floating panel.
-public class FloatingPanelBackdropView: UIView { }

Framework/Sources/FloatingPanelBehavior.swift

@@ -1,110 +0,0 @@
-//
-//  Created by Shin Yamamoto on 2018/10/03.
-//  Copyright © 2018 Shin Yamamoto. All rights reserved.
-//
-
-import UIKit
-
-public protocol FloatingPanelBehavior {
-    /// Returns the progress to redirect to the previous position
-    ///
-    /// The progress is represented by a floating-point value between 0.0 and 1.0, inclusive, where 1.0 indicates the floating panel is impossible to move to the next posiiton. The default value is 0.5. Values less than 0.0 and greater than 1.0 are pinned to those limits.
-    func redirectionalProgress(_ fpc: FloatingPanelController, from: FloatingPanelPosition, to: FloatingPanelPosition) -> CGFloat
-
-    /// Returns a UIViewPropertyAnimator object to project a floating panel to a position on finger up if the user dragged.
-    func interactionAnimator(_ fpc: FloatingPanelController, to targetPosition: FloatingPanelPosition, with velocity: CGVector) -> UIViewPropertyAnimator
-
-    /// Returns a UIViewPropertyAnimator object to add a floating panel to a position.
-    ///
-    /// Its animator instance will be used to animate the surface view in `FloatingPanelController.addPanel(toParent:belowView:animated:)`.
-    /// Default is an animator with ease-in-out curve and 0.25 sec duration.
-    func addAnimator(_ fpc: FloatingPanelController, to: FloatingPanelPosition) -> UIViewPropertyAnimator
-
-    /// Returns a UIViewPropertyAnimator object to remove a floating panel from a position.
-    ///
-    /// Its animator instance will be used to animate the surface view in `FloatingPanelController.removePanelFromParent(animated:completion:)`.
-    /// Default is an animator with ease-in-out curve and 0.25 sec duration.
-    func removeAnimator(_ fpc: FloatingPanelController, from: FloatingPanelPosition) -> UIViewPropertyAnimator
-
-    /// Returns a UIViewPropertyAnimator object to move a floating panel from a position to a position.
-    ///
-    /// Its animator instance will be used to animate the surface view in `FloatingPanelController.move(to:animated:completion:)`.
-    /// Default is an animator with ease-in-out curve and 0.25 sec duration.
-    func moveAnimator(_ fpc: FloatingPanelController, from: FloatingPanelPosition, to: FloatingPanelPosition) -> UIViewPropertyAnimator
-
-    /// Returns a y-axis velocity to invoke a removal interaction at the bottom position.
-    ///
-    /// Default is 10.0. This method is called when FloatingPanelController.isRemovalInteractionEnabled is true.
-    var removalVelocity: CGFloat { get }
-
-    /// Returns the threshold of the transition to invoke a removal interaction at the bottom position.
-    ///
-    /// The progress is represented by a floating-point value between 0.0 and 1.0, inclusive, where 1.0 indicates the floating panel is impossible to invoke the removal interaction. The default value is 0.5. Values less than 0.0 and greater than 1.0 are pinned to those limits. This method is called when FloatingPanelController.isRemovalInteractionEnabled is true.
-    var removalProgress: CGFloat { get }
-
-    /// Returns a UIViewPropertyAnimator object to remove a floating panel with a velocity interactively at the bottom position.
-    ///
-    /// Default is a spring animator with 1.0 damping ratio. This method is called when FloatingPanelController.isRemovalInteractionEnabled is true.
-    func removalInteractionAnimator(_ fpc: FloatingPanelController, with velocity: CGVector) -> UIViewPropertyAnimator
-}
-
-public extension FloatingPanelBehavior {
-    func redirectionalProgress(_ fpc: FloatingPanelController, from: FloatingPanelPosition, to: FloatingPanelPosition) -> CGFloat {
-        return 0.5
-    }
-
-    func addAnimator(_ fpc: FloatingPanelController, to: FloatingPanelPosition) -> UIViewPropertyAnimator {
-        return UIViewPropertyAnimator(duration: 0.25, curve: .easeInOut)
-    }
-
-    func removeAnimator(_ fpc: FloatingPanelController, from: FloatingPanelPosition) -> UIViewPropertyAnimator {
-        return UIViewPropertyAnimator(duration: 0.25, curve: .easeInOut)
-    }
-
-    func moveAnimator(_ fpc: FloatingPanelController, from: FloatingPanelPosition, to: FloatingPanelPosition) -> UIViewPropertyAnimator {
-        return UIViewPropertyAnimator(duration: 0.25, curve: .easeInOut)
-    }
-
-    var removalVelocity: CGFloat {
-        return 10.0
-    }
-
-    var removalProgress: CGFloat {
-        return 0.5
-    }
-
-    func removalInteractionAnimator(_ fpc: FloatingPanelController, with velocity: CGVector) -> UIViewPropertyAnimator {
-        log.debug("velocity", velocity)
-        let timing = UISpringTimingParameters(dampingRatio: 1.0,
-                                        frequencyResponse: 0.3,
-                                        initialVelocity: velocity)
-        return UIViewPropertyAnimator(duration: 0, timingParameters: timing)
-    }
-}
-
-class FloatingPanelDefaultBehavior: FloatingPanelBehavior {
-    func interactionAnimator(_ fpc: FloatingPanelController, to targetPosition: FloatingPanelPosition, with velocity: CGVector) -> UIViewPropertyAnimator {
-        let timing = timeingCurve(with: velocity)
-        let animator = UIViewPropertyAnimator(duration: 0, timingParameters: timing)
-        animator.isInterruptible = false
-        return animator
-    }
-
-    private func timeingCurve(with velocity: CGVector) -> UITimingCurveProvider {
-        log.debug("velocity", velocity)
-        let damping = self.getDamping(with: velocity)
-        return UISpringTimingParameters(dampingRatio: damping,
-                                        frequencyResponse: 0.3,
-                                        initialVelocity: velocity)
-    }
-
-    private let velocityThreshold: CGFloat = 8.0
-    private func getDamping(with velocity: CGVector) -> CGFloat {
-        let dy = abs(velocity.dy)
-        if dy > velocityThreshold {
-            return 0.7
-        } else {
-            return 1.0
-        }
-    }
-}

Framework/Sources/FloatingPanelController.h

@@ -1,9 +0,0 @@
-//
-//  Created by Shin Yamamoto on 2018/09/18.
-//  Copyright © 2018 Shin Yamamoto. All rights reserved.
-//
-
-#import <UIKit/UIKit.h>
-
-FOUNDATION_EXPORT double FloatingPanelVersionNumber;
-FOUNDATION_EXPORT const unsigned char FloatingPanelVersionString[];

Framework/Sources/FloatingPanelController.swift

@@ -1,493 +0,0 @@
-//
-//  Created by Shin Yamamoto on 2018/09/18.
-//  Copyright © 2018 Shin Yamamoto. All rights reserved.
-//
-
-import UIKit
-
-public protocol FloatingPanelControllerDelegate: class {
-    // if it returns nil, FloatingPanelController uses the default layout
-    func floatingPanel(_ vc: FloatingPanelController, layoutFor newCollection: UITraitCollection) -> FloatingPanelLayout?
-
-    // if it returns nil, FloatingPanelController uses the default behavior
-    func floatingPanel(_ vc: FloatingPanelController, behaviorFor newCollection: UITraitCollection) -> FloatingPanelBehavior?
-
-    func floatingPanelDidChangePosition(_ vc: FloatingPanelController) // changed the settled position in the model layer
-
-    func floatingPanelDidMove(_ vc: FloatingPanelController) // any offset changes
-
-    // called on start of dragging (may require some time and or distance to move)
-    func floatingPanelWillBeginDragging(_ vc: FloatingPanelController)
-    // called on finger up if the user dragged. velocity is in points/second.
-    func floatingPanelDidEndDragging(_ vc: FloatingPanelController, withVelocity velocity: CGPoint, targetPosition: FloatingPanelPosition)
-    func floatingPanelWillBeginDecelerating(_ vc: FloatingPanelController) // called on finger up as we are moving
-    func floatingPanelDidEndDecelerating(_ vc: FloatingPanelController) // called when scroll view grinds to a halt
-
-    // called on start of dragging to remove its views from a parent view controller
-    func floatingPanelDidEndDraggingToRemove(_ vc: FloatingPanelController, withVelocity velocity: CGPoint)
-    // called when its views are removed from a parent view controller
-    func floatingPanelDidEndRemove(_ vc: FloatingPanelController)
-
-    func floatingPanel(_ vc: FloatingPanelController, shouldRecognizeSimultaneouslyWith gestureRecognizer: UIGestureRecognizer) -> Bool
-}
-
-public extension FloatingPanelControllerDelegate {
-    func floatingPanel(_ vc: FloatingPanelController, layoutFor newCollection: UITraitCollection) -> FloatingPanelLayout? {
-        return nil
-    }
-    func floatingPanel(_ vc: FloatingPanelController, behaviorFor newCollection: UITraitCollection) -> FloatingPanelBehavior? {
-        return nil
-    }
-    func floatingPanelDidChangePosition(_ vc: FloatingPanelController) {}
-    func floatingPanelDidMove(_ vc: FloatingPanelController) {}
-    func floatingPanelWillBeginDragging(_ vc: FloatingPanelController) {}
-    func floatingPanelDidEndDragging(_ vc: FloatingPanelController, withVelocity velocity: CGPoint, targetPosition: FloatingPanelPosition) {}
-    func floatingPanelWillBeginDecelerating(_ vc: FloatingPanelController) {}
-    func floatingPanelDidEndDecelerating(_ vc: FloatingPanelController) {}
-
-    func floatingPanelDidEndDraggingToRemove(_ vc: FloatingPanelController, withVelocity velocity: CGPoint) {}
-    func floatingPanelDidEndRemove(_ vc: FloatingPanelController) {}
-
-    func floatingPanel(_ vc: FloatingPanelController, shouldRecognizeSimultaneouslyWith gestureRecognizer: UIGestureRecognizer) -> Bool { return false }
-}
-
-public enum FloatingPanelPosition: Int, CaseIterable {
-    case full
-    case half
-    case tip
-    case hidden
-}
-
-///
-/// A container view controller to display a floating panel to present contents in parallel as a user wants.
-///
-public class FloatingPanelController: UIViewController, UIScrollViewDelegate, UIGestureRecognizerDelegate {
-    /// Constants indicating how safe area insets are added to the adjusted content inset.
-    public enum ContentInsetAdjustmentBehavior: Int {
-        case always
-        case never
-    }
-
-    /// The delegate of the floating panel controller object.
-    public weak var delegate: FloatingPanelControllerDelegate?
-
-    /// Returns the surface view managed by the controller object. It's the same as `self.view`.
-    public var surfaceView: FloatingPanelSurfaceView! {
-        return floatingPanel.surfaceView
-    }
-
-    /// Returns the backdrop view managed by the controller object.
-    public var backdropView: FloatingPanelBackdropView! {
-        return floatingPanel.backdropView
-    }
-
-    /// Returns the scroll view that the controller tracks.
-    public weak var scrollView: UIScrollView? {
-        return floatingPanel.scrollView
-    }
-
-    // The underlying gesture recognizer for pan gestures
-    public var panGestureRecognizer: UIPanGestureRecognizer {
-        return floatingPanel.panGesture
-    }
-
-    /// The current position of the floating panel controller's contents.
-    public var position: FloatingPanelPosition {
-        return floatingPanel.state
-    }
-
-    /// The layout object managed by the controller
-    public var layout: FloatingPanelLayout {
-        return floatingPanel.layoutAdapter.layout
-    }
-
-    /// The behavior object managed by the controller
-    public var behavior: FloatingPanelBehavior {
-        return floatingPanel.behavior
-    }
-
-    /// The content insets of the tracking scroll view derived from this safe area
-    public var adjustedContentInsets: UIEdgeInsets {
-        return floatingPanel.layoutAdapter.adjustedContentInsets
-    }
-
-    /// The behavior for determining the adjusted content offsets.
-    ///
-    /// This property specifies how the content area of the tracking scroll view is modified using `adjustedContentInsets`. The default value of this property is FloatingPanelController.ContentInsetAdjustmentBehavior.always.
-    public var contentInsetAdjustmentBehavior: ContentInsetAdjustmentBehavior = .always
-
-    /// A Boolean value that determines whether the removal interaction is enabled.
-    public var isRemovalInteractionEnabled: Bool {
-        set { floatingPanel.isRemovalInteractionEnabled = newValue }
-        get { return floatingPanel.isRemovalInteractionEnabled }
-    }
-
-    /// The view controller responsible for the content portion of the floating panel.
-    public var contentViewController: UIViewController? {
-        set { set(contentViewController: newValue) }
-        get { return _contentViewController }
-    }
-    private var _contentViewController: UIViewController?
-
-    private var floatingPanel: FloatingPanel!
-    private var safeAreaInsetsObservation: NSKeyValueObservation?
-    private let modalTransition = FloatingPanelModalTransition()
-
-    required init?(coder aDecoder: NSCoder) {
-        super.init(coder: aDecoder)
-        setUp()
-    }
-
-    /// Initialize a newly created floating panel controller.
-    public init() {
-        super.init(nibName: nil, bundle: nil)
-        setUp()
-    }
-
-    private func setUp() {
-        _ = FloatingPanelController.dismissSwizzling
-
-        modalPresentationStyle = .custom
-        transitioningDelegate = modalTransition
-
-        floatingPanel = FloatingPanel(self,
-                                      layout: fetchLayout(for: self.traitCollection),
-                                      behavior: fetchBehavior(for: self.traitCollection))
-    }
-
-    // MARK:- Overrides
-
-    /// Creates the view that the controller manages.
-    override public func loadView() {
-        assert(self.storyboard == nil, "Storyboard isn't supported")
-
-        let view = FloatingPanelPassThroughView()
-        view.backgroundColor = .clear
-
-        backdropView.frame = view.bounds
-        view.addSubview(backdropView)
-
-        surfaceView.frame = view.bounds
-        view.addSubview(surfaceView)
-
-        self.view = view as UIView
-    }
-
-    public override func viewDidLayoutSubviews() {
-        super.viewDidLayoutSubviews()
-        if #available(iOS 11.0, *) {}
-        else {
-            // Because {top,bottom}LayoutGuide is managed as a view
-            self.update(safeAreaInsets: layoutInsets)
-        }
-    }
-
-    public override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
-        super.viewWillTransition(to: size, with: coordinator)
-
-        if view.translatesAutoresizingMaskIntoConstraints {
-            view.frame.size = size
-            view.layoutIfNeeded()
-        }
-    }
-
-    public override func willTransition(to newCollection: UITraitCollection, with coordinator: UIViewControllerTransitionCoordinator) {
-        super.willTransition(to: newCollection, with: coordinator)
-
-        // Change layout for a new trait collection
-        reloadLayout(for: newCollection)
-        setUpLayout()
-
-        floatingPanel.behavior = fetchBehavior(for: newCollection)
-    }
-
-    // MARK:- Privates
-
-    private func fetchLayout(for traitCollection: UITraitCollection) -> FloatingPanelLayout {
-        switch traitCollection.verticalSizeClass {
-        case .compact:
-            return self.delegate?.floatingPanel(self, layoutFor: traitCollection) ?? FloatingPanelDefaultLandscapeLayout()
-        default:
-            return self.delegate?.floatingPanel(self, layoutFor: traitCollection) ?? FloatingPanelDefaultLayout()
-        }
-    }
-
-    private func fetchBehavior(for traitCollection: UITraitCollection) -> FloatingPanelBehavior {
-        return self.delegate?.floatingPanel(self, behaviorFor: traitCollection) ?? FloatingPanelDefaultBehavior()
-    }
-
-    private func update(safeAreaInsets: UIEdgeInsets) {
-        // Don't re-layout the surface on SafeArea.Bottom enabled/disabled in interaction progress
-        guard
-            floatingPanel.layoutAdapter.safeAreaInsets != safeAreaInsets,
-            self.floatingPanel.interactionInProgress == false
-        else { return }
-
-        log.debug("Update safeAreaInsets", safeAreaInsets)
-        
-        floatingPanel.layoutAdapter.safeAreaInsets = safeAreaInsets
-
-        setUpLayout()
-
-        switch contentInsetAdjustmentBehavior {
-        case .always:
-            scrollView?.contentInset = adjustedContentInsets
-            scrollView?.scrollIndicatorInsets = adjustedContentInsets
-        default:
-            break
-        }
-    }
-
-    private func reloadLayout(for traitCollection: UITraitCollection) {
-        floatingPanel.layoutAdapter.layout = fetchLayout(for: traitCollection)
-        floatingPanel.layoutAdapter.prepareLayout(in: self)
-    }
-
-    private func setUpLayout() {
-        // preserve the current content offset
-        let contentOffset = scrollView?.contentOffset
-
-        floatingPanel.layoutAdapter.updateHeight()
-        floatingPanel.layoutAdapter.activateLayout(of: floatingPanel.state)
-
-        scrollView?.contentOffset = contentOffset ?? .zero
-    }
-
-    // MARK: - Container view controller interface
-
-    /// Shows the surface view at the initial position defined by the current layout
-    public func show(animated: Bool = false, completion: (() -> Void)? = nil) {
-        // Must apply the current layout here
-        reloadLayout(for: traitCollection)
-        setUpLayout()
-
-        if #available(iOS 11.0, *) {
-            // Must track the safeAreaInsets of `self.view` to update the layout.
-            // There are 2 reasons.
-            // 1. This or the parent VC doesn't call viewSafeAreaInsetsDidChange() on the bottom
-            // inset's update expectedly.
-            // 2. The safe area top inset can be variable on the large title navigation bar(iOS11+).
-            // That's why it needs the observation to keep `adjustedContentInsets` correct.
-            safeAreaInsetsObservation = self.observe(\.view.safeAreaInsets) { [weak self] (vc, chaneg) in
-                guard let self = self else { return }
-                self.update(safeAreaInsets: vc.layoutInsets)
-            }
-        } else {
-            // KVOs for topLayoutGuide & bottomLayoutGuide are not effective.
-            // Instead, update(safeAreaInsets:) is called at `viewDidLayoutSubviews()`
-        }
-
-        move(to: floatingPanel.layoutAdapter.layout.initialPosition,
-             animated: animated,
-             completion: completion)
-    }
-
-    /// Hides the surface view to the hidden position
-    public func hide(animated: Bool = false, completion: (() -> Void)? = nil) {
-        safeAreaInsetsObservation = nil
-        move(to: .hidden,
-             animated: animated,
-             completion: completion)
-    }
-
-    /// Adds the view managed by the controller as a child of the specified view controller.
-    /// - Parameters:
-    ///     - parent: A parent view controller object that displays FloatingPanelController's view. A container view controller object isn't applicable.
-    ///     - belowView: Insert the surface view managed by the controller below the specified view. By default, the surface view will be added to the end of the parent list of subviews.
-    ///     - animated: Pass true to animate the presentation; otherwise, pass false.
-    public func addPanel(toParent parent: UIViewController, belowView: UIView? = nil, animated: Bool = false) {
-        guard self.parent == nil else {
-            log.warning("Already added to a parent(\(parent))")
-            return
-        }
-        precondition((parent is UINavigationController) == false, "UINavigationController displays only one child view controller at a time.")
-        precondition((parent is UITabBarController) == false, "UITabBarController displays child view controllers with a radio-style selection interface")
-        precondition((parent is UISplitViewController) == false, "UISplitViewController manages two child view controllers in a master-detail interface")
-        precondition((parent is UITableViewController) == false, "UITableViewController should not be the parent because the view is a table view so that a floating panel doens't work well")
-        precondition((parent is UICollectionViewController) == false, "UICollectionViewController should not be the parent because the view is a collection view so that a floating panel doens't work well")
-
-        if let belowView = belowView {
-            parent.view.insertSubview(self.view, belowSubview: belowView)
-        } else {
-            parent.view.addSubview(self.view)
-        }
-
-        parent.addChild(self)
-
-        view.frame = parent.view.bounds // Needed for a correct safe area configuration
-        view.translatesAutoresizingMaskIntoConstraints = false
-        NSLayoutConstraint.activate([
-            self.view.topAnchor.constraint(equalTo: parent.view.topAnchor, constant: 0.0),
-            self.view.leftAnchor.constraint(equalTo: parent.view.leftAnchor, constant: 0.0),
-            self.view.rightAnchor.constraint(equalTo: parent.view.rightAnchor, constant: 0.0),
-            self.view.bottomAnchor.constraint(equalTo: parent.view.bottomAnchor, constant: 0.0),
-            ])
-
-        show(animated: animated) { [weak self] in
-            guard let self = self else { return }
-            self.didMove(toParent: parent)
-        }
-    }
-
-    /// Removes the controller and the managed view from its parent view controller
-    /// - Parameters:
-    ///     - animated: Pass true to animate the presentation; otherwise, pass false.
-    ///     - completion: The block to execute after the view controller is dismissed. This block has no return value and takes no parameters. You may specify nil for this parameter.
-    public func removePanelFromParent(animated: Bool, completion: (() -> Void)? = nil) {
-        guard self.parent != nil else {
-            completion?()
-            return
-        }
-
-        hide(animated: animated) { [weak self] in
-            guard let self = self else { return }
-            self.willMove(toParent: nil)
-            self.view.removeFromSuperview()
-            self.removeFromParent()
-            completion?()
-        }
-    }
-
-    /// Moves the position to the specified position.
-    /// - Parameters:
-    ///     - to: Pass a FloatingPanelPosition value to move the surface view to the position.
-    ///     - animated: Pass true to animate the presentation; otherwise, pass false.
-    ///     - completion: The block to execute after the view controller has finished moving. This block has no return value and takes no parameters. You may specify nil for this parameter.
-    public func move(to: FloatingPanelPosition, animated: Bool, completion: (() -> Void)? = nil) {
-        precondition(floatingPanel.layoutAdapter.vc != nil, "Use show(animated:completion)")
-        floatingPanel.move(to: to, animated: animated, completion: completion)
-    }
-
-    /// Sets the view controller responsible for the content portion of the floating panel..
-    public func set(contentViewController: UIViewController?) {
-        if let vc = _contentViewController {
-            vc.willMove(toParent: nil)
-            vc.view.removeFromSuperview()
-            vc.removeFromParent()
-        }
-
-        if let vc = contentViewController {
-            addChild(vc)
-            let surfaceView = floatingPanel.surfaceView
-            surfaceView.add(contentView: vc.view)
-            vc.didMove(toParent: self)
-        }
-
-        _contentViewController = contentViewController
-    }
-    
-    @available(*, unavailable, renamed: "set(contentViewController:)")
-    public override func show(_ vc: UIViewController, sender: Any?) {
-        if let target = self.parent?.targetViewController(forAction: #selector(UIViewController.show(_:sender:)), sender: sender) {
-            target.show(vc, sender: sender)
-        }
-    }
-
-    @available(*, unavailable, renamed: "set(contentViewController:)")
-    public override func showDetailViewController(_ vc: UIViewController, sender: Any?) {
-        if let target = self.parent?.targetViewController(forAction: #selector(UIViewController.showDetailViewController(_:sender:)), sender: sender) {
-            target.showDetailViewController(vc, sender: sender)
-        }
-    }
-
-    // MARK: - Scroll view tracking
-
-    /// Tracks the specified scroll view to correspond with the scroll.
-    ///
-    /// - Attention:
-    ///     The specified scroll view must be already assigned to the delegate property because the controller intermediates between the various delegate methods.
-    ///
-    public func track(scrollView: UIScrollView) {
-        floatingPanel.scrollView = scrollView
-        if scrollView.delegate !== floatingPanel {
-            floatingPanel.userScrollViewDelegate = scrollView.delegate
-            scrollView.delegate = floatingPanel
-        }
-        switch contentInsetAdjustmentBehavior {
-        case .always:
-            if #available(iOS 11.0, *) {
-                scrollView.contentInsetAdjustmentBehavior = .never
-            } else {
-                children.forEach { (vc) in
-                    vc.automaticallyAdjustsScrollViewInsets = false
-                }
-            }
-        default:
-            break
-        }
-    }
-
-    // MARK: - Utilities
-
-    /// Updates the layout object from the delegate and lays out the views managed
-    /// by the controller immediately.
-    ///
-    /// This method updates the `FloatingPanelLayout` object from the delegate and
-    /// then it calls `layoutIfNeeded()` of the root view to force the view
-    /// to update the floating panel's layout immediately. It can be called in an
-    /// animation block.
-    public func updateLayout() {
-        reloadLayout(for: traitCollection)
-        setUpLayout()
-    }
-
-    /// Returns the y-coordinate of the point at the origin of the surface view
-    public func originYOfSurface(for pos: FloatingPanelPosition) -> CGFloat {
-        switch pos {
-        case .full:
-            return floatingPanel.layoutAdapter.topY
-        case .half:
-            return floatingPanel.layoutAdapter.middleY
-        case .tip:
-            return floatingPanel.layoutAdapter.bottomY
-        case .hidden:
-            return floatingPanel.layoutAdapter.hiddenY
-        }
-    }
-}
-
-extension FloatingPanelController {
-    private static let dismissSwizzling: Any? = {
-        let aClass: AnyClass! = UIViewController.self //object_getClass(vc)
-        if let imp = class_getMethodImplementation(aClass, #selector(dismiss(animated:completion:))),
-            let originalAltMethod = class_getInstanceMethod(aClass, #selector(fp_original_dismiss(animated:completion:))) {
-            method_setImplementation(originalAltMethod, imp)
-        }
-        let originalMethod = class_getInstanceMethod(aClass, #selector(dismiss(animated:completion:)))
-        let swizzledMethod = class_getInstanceMethod(aClass, #selector(fp_dismiss(animated:completion:)))
-        if let originalMethod = originalMethod, let swizzledMethod = swizzledMethod {
-            // switch implementation..
-            method_exchangeImplementations(originalMethod, swizzledMethod)
-        }
-        return nil
-    }()
-}
-
-public extension UIViewController {
-    @objc public func fp_original_dismiss(animated flag: Bool, completion: (() -> Void)? = nil) {
-        // Implementation will be replaced by IMP of self.dismiss(animated:completion:)
-    }
-    @objc public func fp_dismiss(animated flag: Bool, completion: (() -> Void)? = nil) {
-        // Call dismiss(animated:completion:) to a content view controller
-        if let fpc = parent as? FloatingPanelController {
-            if fpc.presentingViewController != nil {
-                self.fp_original_dismiss(animated: flag, completion: completion)
-            } else {
-                fpc.removePanelFromParent(animated: flag, completion: completion)
-            }
-            return
-        }
-        // Call dismiss(animated:completion:) to FloatingPanelController directly
-        if let fpc = self as? FloatingPanelController {
-            if fpc.presentingViewController != nil {
-                self.fp_original_dismiss(animated: flag, completion: completion)
-            } else {
-                fpc.removePanelFromParent(animated: flag, completion: completion)
-            }
-            return
-        }
-
-        // For other view controllers
-        self.fp_original_dismiss(animated: flag, completion: completion)
-    }
-}

Framework/Sources/FloatingPanelLayout.swift

@@ -1,377 +0,0 @@
-//
-//  Created by Shin Yamamoto on 2018/09/27.
-//  Copyright © 2018 Shin Yamamoto. All rights reserved.
-//
-
-import UIKit
-
-/// FloatingPanelIntrinsicLayout
-///
-/// - Attention:
-///     `insetFor(position:)` must return `nil` for full position because the inset is determined automatically.
-///     You can customize insets only for half, tip and hidden positions
-///     on FloatingPanelIntrinsicLayout.
-public protocol FloatingPanelIntrinsicLayout: FloatingPanelLayout { }
-
-public extension FloatingPanelIntrinsicLayout {
-    var initialPosition: FloatingPanelPosition {
-        return .full
-    }
-
-    var supportedPositions: Set<FloatingPanelPosition> {
-        return [.full]
-    }
-
-    func insetFor(position: FloatingPanelPosition) -> CGFloat? {
-        return nil
-    }
-}
-
-public protocol FloatingPanelLayout: class {
-    /// Returns the initial position of a floating panel.
-    var initialPosition: FloatingPanelPosition { get }
-
-    /// Returns a set of FloatingPanelPosition objects to tell the applicable
-    /// positions of the floating panel controller.
-    ///
-    /// By default, it returns all position exepct for `hidden` position. Because
-    /// it's always supported by `FloatingPanelController` so you don't need to return it.
-    var supportedPositions: Set<FloatingPanelPosition> { get }
-
-    /// Return the interaction buffer to the top from the top position. Default is 6.0.
-    var topInteractionBuffer: CGFloat { get }
-
-    /// Return the interaction buffer to the bottom from the bottom position. Default is 6.0.
-    var bottomInteractionBuffer: CGFloat { get }
-
-    /// Returns a CGFloat value to determine a Y coordinate of a floating panel for each position(full, half, tip and hidden).
-    ///
-    /// Its returning value indicates a different inset for each positiion.
-    /// For full position, a top inset from a safe area in `FloatingPanelController.view`.
-    /// For half or tip position, a bottom inset from the safe area.
-    /// For hidden position, a bottom inset from `FloatingPanelController.view`.
-    /// If a position isn't supported or the default value is used, return nil.
-    func insetFor(position: FloatingPanelPosition) -> CGFloat?
-
-    /// Returns X-axis and width layout constraints of the surface view of a floating panel.
-    /// You must not include any Y-axis and height layout constraints of the surface view
-    /// because their constraints will be configured by the floating panel controller.
-    /// By default, the width of a surface view fits a safe area.
-    func prepareLayout(surfaceView: UIView, in view: UIView) -> [NSLayoutConstraint]
-
-    /// Returns a CGFloat value to determine the backdrop view's alpha for a position.
-    ///
-    /// Default is 0.3 at full position, otherwise 0.0.
-    func backdropAlphaFor(position: FloatingPanelPosition) -> CGFloat
-}
-
-public extension FloatingPanelLayout {
-    var topInteractionBuffer: CGFloat { return 6.0 }
-    var bottomInteractionBuffer: CGFloat { return 6.0 }
-
-    var supportedPositions: Set<FloatingPanelPosition> {
-        return Set([.full, .half, .tip])
-    }
-    
-    func prepareLayout(surfaceView: UIView, in view: UIView) -> [NSLayoutConstraint] {
-        return [
-            surfaceView.leftAnchor.constraint(equalTo: view.sideLayoutGuide.leftAnchor, constant: 0.0),
-            surfaceView.rightAnchor.constraint(equalTo: view.sideLayoutGuide.rightAnchor, constant: 0.0),
-        ]
-    }
-
-    func backdropAlphaFor(position: FloatingPanelPosition) -> CGFloat {
-        return position == .full ? 0.3 : 0.0
-    }
-}
-
-public class FloatingPanelDefaultLayout: FloatingPanelLayout {
-    public var initialPosition: FloatingPanelPosition {
-        return .half
-    }
-
-    public func insetFor(position: FloatingPanelPosition) -> CGFloat? {
-        switch position {
-        case .full: return 18.0
-        case .half: return 262.0
-        case .tip: return 69.0
-        case .hidden: return nil
-        }
-    }
-}
-
-public class FloatingPanelDefaultLandscapeLayout: FloatingPanelLayout {
-    public var initialPosition: FloatingPanelPosition {
-        return .tip
-    }
-    public var supportedPositions: Set<FloatingPanelPosition> {
-        return [.full, .tip]
-    }
-
-    public func insetFor(position: FloatingPanelPosition) -> CGFloat? {
-        switch position {
-        case .full: return 16.0
-        case .tip: return 69.0
-        default: return nil
-        }
-    }
-}
-
-
-class FloatingPanelLayoutAdapter {
-    weak var vc: UIViewController!
-    private weak var surfaceView: FloatingPanelSurfaceView!
-    private weak var backdropView: FloatingPanelBackdropView!
-
-    var layout: FloatingPanelLayout {
-        didSet {
-            checkLayoutConsistance()
-        }
-    }
-
-    var safeAreaInsets: UIEdgeInsets = .zero
-
-    private var heightBuffer: CGFloat = 88.0 // For bounce
-    private var fixedConstraints: [NSLayoutConstraint] = []
-    private var fullConstraints: [NSLayoutConstraint] = []
-    private var halfConstraints: [NSLayoutConstraint] = []
-    private var tipConstraints: [NSLayoutConstraint] = []
-    private var offConstraints: [NSLayoutConstraint] = []
-    private var heightConstraints: [NSLayoutConstraint] = []
-
-    private var fullInset: CGFloat {
-        if layout is FloatingPanelIntrinsicLayout {
-            return intrinsicHeight
-        } else {
-            return layout.insetFor(position: .full) ?? 0.0
-        }
-    }
-    private var halfInset: CGFloat {
-        return layout.insetFor(position: .half) ?? 0.0
-    }
-    private var tipInset: CGFloat {
-        return layout.insetFor(position: .tip) ?? 0.0
-    }
-    private var hiddenInset: CGFloat {
-        return layout.insetFor(position: .hidden) ?? 0.0
-    }
-
-    var supportedPositions: Set<FloatingPanelPosition> {
-        var supportedPositions = layout.supportedPositions
-        supportedPositions.remove(.hidden)
-        return supportedPositions
-    }
-
-    var topY: CGFloat {
-        if supportedPositions.contains(.full) {
-            if layout is FloatingPanelIntrinsicLayout {
-                return surfaceView.superview!.bounds.height - surfaceView.bounds.height
-            } else {
-                return (safeAreaInsets.top + fullInset)
-            }
-        } else {
-            return middleY
-        }
-    }
-
-    var middleY: CGFloat {
-        return surfaceView.superview!.bounds.height - (safeAreaInsets.bottom + halfInset)
-    }
-
-    var bottomY: CGFloat {
-        if supportedPositions.contains(.tip) {
-            return surfaceView.superview!.bounds.height - (safeAreaInsets.bottom + tipInset)
-        } else {
-            return middleY
-        }
-    }
-
-    var hiddenY: CGFloat {
-        return surfaceView.superview!.bounds.height
-    }
-
-    var safeAreaBottomY: CGFloat {
-        return surfaceView.superview!.bounds.height - (safeAreaInsets.bottom + hiddenInset)
-    }
-
-    var topMaxY: CGFloat { return -safeAreaInsets.top }
-    var bottomMaxY: CGFloat { return safeAreaBottomY }
-
-    var adjustedContentInsets: UIEdgeInsets {
-        return UIEdgeInsets(top: 0.0,
-                            left: 0.0,
-                            bottom: safeAreaInsets.bottom,
-                            right: 0.0)
-    }
-
-    func positionY(for pos: FloatingPanelPosition) -> CGFloat {
-        switch pos {
-        case .full:
-            return topY
-        case .half:
-            return middleY
-        case .tip:
-            return bottomY
-        case .hidden:
-            return hiddenY
-        }
-    }
-
-    var intrinsicHeight: CGFloat = 0.0
-
-    init(surfaceView: FloatingPanelSurfaceView, backdropView: FloatingPanelBackdropView, layout: FloatingPanelLayout) {
-        self.layout = layout
-        self.surfaceView = surfaceView
-        self.backdropView = backdropView
-    }
-
-    func updateIntrinsicHeight() {
-        let fittingSize = UIView.layoutFittingCompressedSize
-        var intrinsicHeight = surfaceView.contentView?.systemLayoutSizeFitting(fittingSize).height ?? 0.0
-        var safeAreaBottom: CGFloat = 0.0
-        if #available(iOS 11.0, *) {
-            safeAreaBottom = surfaceView.contentView?.safeAreaInsets.bottom ?? 0.0
-            if safeAreaBottom > 0 {
-                intrinsicHeight -= safeAreaInsets.bottom
-            }
-        }
-        self.intrinsicHeight = max(intrinsicHeight, 0.0)
-
-        log.debug("Update intrinsic height =", intrinsicHeight,
-                  ", surface(height) =", surfaceView.frame.height,
-                  ", content(height) =", surfaceView.contentView?.frame.height ?? 0.0,
-                  ", content safe area(bottom) =", safeAreaBottom)
-    }
-
-    func prepareLayout(in vc: UIViewController) {
-        self.vc = vc
-
-        NSLayoutConstraint.deactivate(fixedConstraints + fullConstraints + halfConstraints + tipConstraints + offConstraints)
-
-        surfaceView.translatesAutoresizingMaskIntoConstraints = false
-        backdropView.translatesAutoresizingMaskIntoConstraints = false
-
-        // Fixed constraints of surface and backdrop views
-        let surfaceConstraints = layout.prepareLayout(surfaceView: surfaceView, in: vc.view!)
-        let backdropConstraints = [
-            backdropView.topAnchor.constraint(equalTo: vc.view.topAnchor, constant: 0.0),
-            backdropView.leftAnchor.constraint(equalTo: vc.view.leftAnchor,constant: 0.0),
-            backdropView.rightAnchor.constraint(equalTo: vc.view.rightAnchor, constant: 0.0),
-            backdropView.bottomAnchor.constraint(equalTo: vc.view.bottomAnchor, constant: 0.0),
-            ]
-
-        fixedConstraints = surfaceConstraints + backdropConstraints
-
-        // Flexible surface constarints for full, half, tip and off
-        if layout is FloatingPanelIntrinsicLayout {
-            // Set up on updateHeight()
-        } else {
-            fullConstraints = [
-                surfaceView.topAnchor.constraint(equalTo: vc.layoutGuide.topAnchor,
-                                                 constant: fullInset),
-            ]
-        }
-        halfConstraints = [
-            surfaceView.topAnchor.constraint(equalTo: vc.layoutGuide.bottomAnchor,
-                                             constant: -halfInset),
-        ]
-        tipConstraints = [
-            surfaceView.topAnchor.constraint(equalTo: vc.layoutGuide.bottomAnchor,
-                                             constant: -tipInset),
-        ]
-        offConstraints = [
-            surfaceView.topAnchor.constraint(equalTo: vc.view.bottomAnchor,
-                                             constant: -hiddenInset),
-        ]
-    }
-
-    // The method is separated from prepareLayout(to:) for the rotation support
-    // It must be called in FloatingPanelController.traitCollectionDidChange(_:)
-    func updateHeight() {
-        guard let vc = vc else { return }
-
-        NSLayoutConstraint.deactivate(heightConstraints)
-
-        if layout is FloatingPanelIntrinsicLayout {
-            updateIntrinsicHeight()
-            heightConstraints = [
-                surfaceView.heightAnchor.constraint(equalToConstant: intrinsicHeight + safeAreaInsets.bottom),
-            ]
-        } else {
-            heightConstraints = [
-                surfaceView.heightAnchor.constraint(equalTo: vc.view.heightAnchor,
-                                                    constant: -(safeAreaInsets.top + fullInset)),
-            ]
-        }
-        NSLayoutConstraint.activate(heightConstraints)
-
-        surfaceView.bottomOverflow = heightBuffer + layout.topInteractionBuffer
-
-        if layout is FloatingPanelIntrinsicLayout {
-            NSLayoutConstraint.deactivate(fullConstraints)
-            fullConstraints = [
-                surfaceView.topAnchor.constraint(equalTo: vc.layoutGuide.bottomAnchor,
-                                                 constant: -fullInset),
-            ]
-        }
-    }
-
-    func activateLayout(of state: FloatingPanelPosition) {
-        defer {
-            surfaceView.superview!.layoutIfNeeded()
-        }
-
-        var state = state
-
-        setBackdropAlpha(of: state)
-
-        NSLayoutConstraint.activate(fixedConstraints)
-
-        if supportedPositions.union([.hidden]).contains(state) == false {
-            state = layout.initialPosition
-        }
-
-        NSLayoutConstraint.deactivate(fullConstraints + halfConstraints + tipConstraints + offConstraints)
-        switch state {
-        case .full:
-            NSLayoutConstraint.activate(fullConstraints)
-        case .half:
-            NSLayoutConstraint.activate(halfConstraints)
-        case .tip:
-            NSLayoutConstraint.activate(tipConstraints)
-        case .hidden:
-            NSLayoutConstraint.activate(offConstraints)
-        }
-    }
-
-    func setBackdropAlpha(of target: FloatingPanelPosition) {
-        if target == .hidden {
-            self.backdropView.alpha = 0.0
-        } else {
-            self.backdropView.alpha = layout.backdropAlphaFor(position: target)
-        }
-    }
-
-    private func checkLayoutConsistance() {
-        // Verify layout configurations
-        assert(supportedPositions.count > 0)
-        assert(supportedPositions.contains(layout.initialPosition),
-               "Does not include an initial potision(\(layout.initialPosition)) in supportedPositions(\(supportedPositions))")
-
-        if layout is FloatingPanelIntrinsicLayout {
-            assert(layout.insetFor(position: .full) == nil, "Return `nil` for full position on FloatingPanelIntrinsicLayout")
-        }
-
-        if halfInset > 0 {
-            assert(halfInset > tipInset, "Invalid half and tip insets")
-        }
-        // The verification isn't working on orientation change(portrait -> landscape)
-        // of a floating panel in tab bar. Because the `safeAreaInsets.bottom` is
-        // updated in delay so that it can be 83.0(not 53.0) even after the surface
-        // and the super view's frame is fit to landscape already.
-        /*if fullInset > 0 {
-            assert(middleY > topY, "Invalid insets { topY: \(topY), middleY: \(middleY) }")
-            assert(bottomY > topY, "Invalid insets { topY: \(topY), bottomY: \(bottomY) }")
-         }*/
-    }
-}

Framework/Sources/FloatingPanelSurfaceView.swift

@@ -1,161 +0,0 @@
-//
-//  Created by Shin Yamamoto on 2018/09/26.
-//  Copyright © 2018 Shin Yamamoto. All rights reserved.
-//
-
-import UIKit
-
-class FloatingPanelSurfaceContentView: UIView {}
-
-/// A view that presents a surface interface in a floating panel.
-public class FloatingPanelSurfaceView: UIView {
-
-    /// A GrabberHandleView object displayed at the top of the surface view.
-    ///
-    /// To use a custom grabber handle, hide this and then add the custom one
-    /// to the surface view at appropirate coordinates.
-    public var grabberHandle: GrabberHandleView!
-
-    /// The height of the grabber bar area
-    public static var topGrabberBarHeight: CGFloat {
-        return Default.grabberTopPadding * 2 + GrabberHandleView.Default.height // 17.0
-    }
-
-    /// A root view of a content view controller
-    public weak var contentView: UIView!
-
-    private var color: UIColor? = .white { didSet { setNeedsLayout() } }
-    var bottomOverflow: CGFloat = 0.0 // Must not call setNeedsLayout()
-
-    public override var backgroundColor: UIColor? {
-        get { return color }
-        set { color = newValue }
-    }
-
-    /// The radius to use when drawing top rounded corners.
-    ///
-    /// `self.contentView` is masked with the top rounded corners automatically on iOS 11 and later.
-    /// On iOS 10, they are not automatically masked because of a UIVisualEffectView issue. See https://forums.developer.apple.com/thread/50854
-    public var cornerRadius: CGFloat = 0.0 { didSet { setNeedsLayout() } }
-
-    /// A Boolean indicating whether the surface shadow is displayed.
-    public var shadowHidden: Bool = false  { didSet { setNeedsLayout() } }
-
-    /// The color of the surface shadow.
-    public var shadowColor: UIColor = .black  { didSet { setNeedsLayout() } }
-
-    /// The offset (in points) of the surface shadow.
-    public var shadowOffset: CGSize = CGSize(width: 0.0, height: 1.0)  { didSet { setNeedsLayout() } }
-
-    /// The opacity of the surface shadow.
-    public var shadowOpacity: Float = 0.2 { didSet { setNeedsLayout() } }
-
-    /// The blur radius (in points) used to render the surface shadow.
-    public var shadowRadius: CGFloat = 3  { didSet { setNeedsLayout() } }
-
-    /// The width of the surface border.
-    public var borderColor: UIColor?  { didSet { setNeedsLayout() } }
-
-    /// The color of the surface border.
-    public var borderWidth: CGFloat = 0.0  { didSet { setNeedsLayout() } }
-
-    private var backgroundLayer: CAShapeLayer!  { didSet { setNeedsLayout() } }
-
-    private struct Default {
-        public static let grabberTopPadding: CGFloat = 6.0
-    }
-
-    override init(frame: CGRect) {
-        super.init(frame: frame)
-        render()
-    }
-
-    required init?(coder aDecoder: NSCoder) {
-        super.init(coder: aDecoder)
-        render()
-    }
-
-    private func render() {
-        super.backgroundColor = .clear
-        self.clipsToBounds = false
-
-        let backgroundLayer = CAShapeLayer()
-        layer.insertSublayer(backgroundLayer, at: 0)
-        self.backgroundLayer = backgroundLayer
-
-        let grabberHandle = GrabberHandleView()
-        addSubview(grabberHandle)
-        self.grabberHandle = grabberHandle
-
-        grabberHandle.translatesAutoresizingMaskIntoConstraints = false
-        NSLayoutConstraint.activate([
-            grabberHandle.topAnchor.constraint(equalTo: topAnchor, constant: Default.grabberTopPadding),
-            grabberHandle.widthAnchor.constraint(equalToConstant: grabberHandle.frame.width),
-            grabberHandle.heightAnchor.constraint(equalToConstant: grabberHandle.frame.height),
-            grabberHandle.centerXAnchor.constraint(equalTo: centerXAnchor),
-            ])
-    }
-
-    public override func layoutSubviews() {
-        super.layoutSubviews()
-        log.debug("SurfaceView frame", frame)
-
-        updateLayers()
-        updateContentViewMask()
-
-        contentView?.layer.borderColor = borderColor?.cgColor
-        contentView?.layer.borderWidth = borderWidth
-        contentView?.frame = bounds
-    }
-
-    private func updateLayers() {
-        log.debug("SurfaceView bounds", bounds)
-        
-        var rect = bounds
-        rect.size.height += bottomOverflow // Expand the height for overflow buffer
-        let path = UIBezierPath(roundedRect: rect,
-                                byRoundingCorners: [.topLeft, .topRight],
-                                cornerRadii: CGSize(width: cornerRadius, height: cornerRadius))
-        backgroundLayer.path = path.cgPath
-        backgroundLayer.fillColor = color?.cgColor
-		
-        if shadowHidden == false {
-            layer.shadowColor = shadowColor.cgColor
-            layer.shadowOffset = shadowOffset
-            layer.shadowOpacity = shadowOpacity
-            layer.shadowRadius = shadowRadius
-        }
-    }
-
-    private func updateContentViewMask() {
-        if #available(iOS 11, *) {
-            // Don't use `contentView.clipToBounds` because it prevents content view from expanding the height of a subview of it
-            // for the bottom overflow like Auto Layout settings of UIVisualEffectView in Main.storyborad of Example/Maps.
-            // Because the bottom of contentView must be fit to the bottom of a screen to work the `safeLayoutGuide` of a content VC.
-            let maskLayer = CAShapeLayer()
-            var rect = bounds
-            rect.size.height += bottomOverflow
-            let path = UIBezierPath(roundedRect: rect,
-                                    byRoundingCorners: [.topLeft, .topRight],
-                                    cornerRadii: CGSize(width: cornerRadius, height: cornerRadius))
-            maskLayer.path = path.cgPath
-            contentView?.layer.mask = maskLayer
-        } else {
-            // Don't use `contentView.layer.mask` because of a UIVisualEffectView issue in iOS 10, https://forums.developer.apple.com/thread/50854
-            // Instead, a user can mask the content view manually in an application.
-        }
-    }
-
-    func add(contentView: UIView) {
-        insertSubview(contentView, belowSubview: grabberHandle)
-        self.contentView = contentView
-        /* contentView.frame = bounds */ // MUST NOT: Because the top safe area inset of a content VC will be incorrect.
-        contentView.translatesAutoresizingMaskIntoConstraints = false
-        NSLayoutConstraint.activate([
-            contentView.topAnchor.constraint(equalTo: topAnchor, constant: 0.0),
-            contentView.leftAnchor.constraint(equalTo: leftAnchor, constant: 0.0),
-            contentView.rightAnchor.constraint(equalTo: rightAnchor, constant: 0.0),
-            contentView.bottomAnchor.constraint(equalTo: bottomAnchor, constant: 0.0),
-            ])
-    }
-}

Framework/Sources/FloatingPanelTransitioning.swift

@@ -1,112 +0,0 @@
-//
-//  Created by Shin Yamamoto on 2018/11/21.
-//  Copyright © 2018 Shin Yamamoto. All rights reserved.
-//
-
-import UIKit
-
-class FloatingPanelModalTransition: NSObject, UIViewControllerTransitioningDelegate {
-    func animationController(forPresented presented: UIViewController,
-                             presenting: UIViewController,
-                             source: UIViewController) -> UIViewControllerAnimatedTransitioning? {
-        return FloatingPanelModalPresentTransition()
-    }
-
-    func animationController(forDismissed dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning? {
-        return FloatingPanelModalDismissTransition()
-    }
-
-    func presentationController(forPresented presented: UIViewController, presenting: UIViewController?, source: UIViewController) -> UIPresentationController? {
-        return FloatingPanelPresentationController(presentedViewController: presented, presenting: presenting)
-    }
-}
-
-class FloatingPanelPresentationController: UIPresentationController {
-    override func presentationTransitionWillBegin() { }
-
-    override func presentationTransitionDidEnd(_ completed: Bool) {
-        // For non-animated presentation
-        if let fpc = presentedViewController as? FloatingPanelController, fpc.position == .hidden {
-            fpc.show(animated: false, completion: nil)
-        }
-    }
-
-    override func dismissalTransitionDidEnd(_ completed: Bool) {
-        if let fpc = presentedViewController as? FloatingPanelController {
-            // For non-animated dismissal
-            if fpc.position != .hidden {
-                fpc.hide(animated: false, completion: nil)
-            }
-            fpc.view.removeFromSuperview()
-        }
-
-    }
-
-    override func containerViewWillLayoutSubviews() {
-        guard
-            let containerView = self.containerView,
-            let fpc = presentedViewController as? FloatingPanelController,
-            let fpView = fpc.view
-            else { fatalError() }
-
-        containerView.addSubview(fpView)
-        fpView.frame = containerView.bounds
-        fpView.translatesAutoresizingMaskIntoConstraints = false
-        NSLayoutConstraint.activate([
-            fpView.topAnchor.constraint(equalTo: containerView.topAnchor, constant: 0.0),
-            fpView.leftAnchor.constraint(equalTo: containerView.leftAnchor, constant: 0.0),
-            fpView.rightAnchor.constraint(equalTo: containerView.rightAnchor, constant: 0.0),
-            fpView.bottomAnchor.constraint(equalTo: containerView.bottomAnchor, constant: 0.0),
-            ])
-
-        let tapGesture = UITapGestureRecognizer(target: self, action: #selector(handleBackdrop(tapGesture:)))
-        fpc.backdropView.addGestureRecognizer(tapGesture)
-    }
-
-    @objc func handleBackdrop(tapGesture: UITapGestureRecognizer) {
-        presentedViewController.dismiss(animated: true, completion: nil)
-    }
-}
-
-class FloatingPanelModalPresentTransition: NSObject, UIViewControllerAnimatedTransitioning {
-    func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
-        guard
-            let fpc = transitionContext?.viewController(forKey: .to) as? FloatingPanelController
-        else { fatalError()}
-
-        let animator = fpc.behavior.addAnimator(fpc, to: fpc.layout.initialPosition)
-        return TimeInterval(animator.duration)
-    }
-
-    func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
-        guard
-            let fpc = transitionContext.viewController(forKey: .to) as? FloatingPanelController
-        else { fatalError() }
-
-        fpc.show(animated: true) {
-            transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
-        }
-    }
-}
-
-class FloatingPanelModalDismissTransition: NSObject, UIViewControllerAnimatedTransitioning {
-    func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
-        guard
-            let fpc = transitionContext?.viewController(forKey: .from) as? FloatingPanelController
-        else { fatalError()}
-
-        let animator = fpc.behavior.removeAnimator(fpc, from: fpc.position)
-        return TimeInterval(animator.duration)
-    }
-
-    func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
-        guard
-            let fpc = transitionContext.viewController(forKey: .from) as? FloatingPanelController
-        else { fatalError() }
-
-        fpc.hide(animated: true) {
-            transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
-        }
-    }
-}
-

Framework/Sources/FloatingPanelView.swift

@@ -1,18 +0,0 @@
-//
-//  Created by Shin Yamamoto on 2018/11/21.
-//  Copyright © 2018 Shin Yamamoto. All rights reserved.
-//
-
-import UIKit
-
-class FloatingPanelPassThroughView: UIView {
-    public override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
-        let view = super.hitTest(point, with: event)
-        switch view {
-        case is FloatingPanelPassThroughView:
-            return nil
-        default:
-            return view
-        }
-    }
-}

Framework/Sources/GrabberHandleView.swift

@@ -1,37 +0,0 @@
-//
-//  Created by Shin Yamamoto on 2018/09/19.
-//  Copyright © 2018 Shin Yamamoto. All rights reserved.
-//
-
-import UIKit
-
-public class GrabberHandleView: UIView {
-    public struct Default {
-        public static let width: CGFloat = 36.0
-        public static let height: CGFloat = 5.0
-        public static let barColor = UIColor(displayP3Red: 0.76, green: 0.77, blue: 0.76, alpha: 1.0)
-    }
-
-    required init?(coder aDecoder: NSCoder) {
-        super.init(coder: aDecoder)
-        render()
-    }
-
-    init() {
-        let size = CGSize(width: Default.width,
-                          height: Default.height)
-        super.init(frame: CGRect(origin: .zero, size: size))
-        self.backgroundColor = Default.barColor
-        render()
-    }
-
-    private func render() {
-        self.layer.masksToBounds = true
-        self.layer.cornerRadius = frame.size.height * 0.5
-    }
-
-    public override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
-        let view = super.hitTest(point, with: event)
-        return view == self ? nil : view
-    }
-}

Framework/Sources/Logger.swift

@@ -1,106 +0,0 @@
-//
-//  Created by Shin Yamamoto on 2018/10/09.
-//  Copyright © 2018 Shin Yamamoto. All rights reserved.
-//
-
-import Foundation
-import os.log
-
-var log = {
-    return Logger()
-}()
-
-struct Logger {
-    private let osLog: OSLog
-    private let s = DispatchSemaphore(value: 1)
-
-    enum Level: Int, Comparable {
-        case debug = 0
-        case info = 1
-        case warning = 2
-        case error = 3
-        case fault = 4
-
-        var name: String {
-            switch self {
-            case .debug: return "DEBUG"
-            case .info: return "INFO"
-            case .warning: return "WARNING"
-            case .error: return "ERROR"
-            case .fault: return "FAULT"
-            }
-        }
-        var shortName: String {
-            switch self {
-            case .debug:
-                return "D/"
-            case .info:
-                return "I/"
-            case .warning:
-                return "W/"
-            case .error:
-                return "E/"
-            case .fault:
-                return "F/"
-            }
-        }
-        @available(iOS 10.0, *)
-        var osLogType: OSLogType {
-            switch self {
-            case .debug: return .debug
-            case .info: return .info
-            case .warning: return .info
-            case .error: return .error
-            case .fault: return .fault
-            }
-        }
-
-        public static func < (lhs: Logger.Level, rhs: Logger.Level) -> Bool {
-            return lhs.rawValue < rhs.rawValue
-        }
-    }
-
-    init() {
-        osLog = OSLog(subsystem: "com.scenee.FloatingPanel", category: "FloatingPanel")
-    }
-
-    private func log(_ level: Level, _ message: Any, _ arguments: [Any], function: String, line: UInt) {
-        #if __FP_LOG
-        _ = s.wait(timeout: .now() + 0.033)
-        defer { s.signal() }
-
-        let extraMessage: String = arguments.map({ String(describing: $0) }).joined(separator: " ")
-        let log = "\(level.shortName) \(message) \(extraMessage) (\(function):\(line))"
-
-        os_log("%@", log: osLog, type: level.osLogType, log)
-        #endif
-    }
-
-    private func getPrettyFunction(_ function: String, _ file: String) -> String {
-        if let filename = file.split(separator: "/").last {
-            return filename + ":" + function
-        } else {
-            return file + ":" + function
-        }
-    }
-
-    func debug(_ log: Any, _ arguments: Any..., function: String = #function, file: String  = #file, line: UInt = #line) {
-        self.log(.debug, log, arguments, function: getPrettyFunction(function, file), line: line)
-    }
-
-    func info(_ log: Any, _ arguments: Any..., function: String = #function, file: String  = #file, line: UInt = #line) {
-        self.log(.info, log, arguments, function: getPrettyFunction(function, file), line: line)
-    }
-
-    func warning(_ log: Any, _ arguments: Any..., function: String = #function, file: String  = #file, line: UInt = #line) {
-        self.log(.warning, log, arguments, function: getPrettyFunction(function, file), line: line)
-    }
-
-    func error(_ log: Any, _ arguments: Any..., function: String = #function, file: String  = #file, line: UInt = #line) {
-        self.log(.error, log, arguments, function: getPrettyFunction(function, file), line: line)
-    }
-
-    func fault(_ log: Any, _ arguments: Any..., function: String = #function, file: String  = #file, line: UInt = #line) {
-        self.log(.fault, log, arguments, function: getPrettyFunction(function, file), line: line)
-    }
-}

Framework/Sources/UIExtensions.swift

@@ -1,102 +0,0 @@
-//
-//  Created by Shin Yamamoto on 2018/09/18.
-//  Copyright © 2018 Shin Yamamoto. All rights reserved.
-//
-
-import UIKit
-
-protocol LayoutGuideProvider {
-    var topAnchor: NSLayoutYAxisAnchor { get }
-    var bottomAnchor: NSLayoutYAxisAnchor { get }
-}
-extension UILayoutGuide: LayoutGuideProvider {}
-
-class CustomLayoutGuide: LayoutGuideProvider {
-    let topAnchor: NSLayoutYAxisAnchor
-    let bottomAnchor: NSLayoutYAxisAnchor
-    init(topAnchor: NSLayoutYAxisAnchor, bottomAnchor: NSLayoutYAxisAnchor) {
-        self.topAnchor = topAnchor
-        self.bottomAnchor = bottomAnchor
-    }
-}
-
-extension UIViewController {
-    var layoutInsets: UIEdgeInsets {
-        if #available(iOS 11.0, *) {
-            return view.safeAreaInsets
-        } else {
-            return UIEdgeInsets(top: topLayoutGuide.length,
-                                left: 0.0,
-                                bottom: bottomLayoutGuide.length,
-                                right: 0.0)
-        }
-    }
-
-    var layoutGuide: LayoutGuideProvider {
-        if #available(iOS 11.0, *) {
-            return view!.safeAreaLayoutGuide
-        } else {
-            return CustomLayoutGuide(topAnchor: topLayoutGuide.bottomAnchor,
-                                     bottomAnchor: bottomLayoutGuide.topAnchor)
-        }
-    }
-}
-
-protocol SideLayoutGuideProvider {
-    var leftAnchor: NSLayoutXAxisAnchor { get }
-    var rightAnchor: NSLayoutXAxisAnchor { get }
-}
-
-extension UIView: SideLayoutGuideProvider {}
-extension UILayoutGuide: SideLayoutGuideProvider {}
-
-// The reason why UIView has no extensions of safe area insets and top/bottom guides
-// is for iOS10 compat.
-extension UIView {
-    var sideLayoutGuide: SideLayoutGuideProvider {
-        if #available(iOS 11.0, *) {
-            return safeAreaLayoutGuide
-        } else {
-            return self
-        }
-    }
-}
-
-extension UIView {
-    func disableAutoLayout() {
-        let frame = self.frame
-        translatesAutoresizingMaskIntoConstraints = true
-        self.frame = frame
-    }
-    func enableAutoLayout() {
-        translatesAutoresizingMaskIntoConstraints = false
-    }
-}
-
-extension UIGestureRecognizer.State: CustomDebugStringConvertible {
-    public var debugDescription: String {
-        switch self {
-        case .began: return "Began"
-        case .changed: return "Changed"
-        case .failed: return "Failed"
-        case .cancelled: return "Cancelled"
-        case .ended: return "Endeded"
-        case .possible: return "Possible"
-        }
-    }
-}
-
-extension UIScrollView {
-    var contentOffsetZero: CGPoint {
-        return CGPoint(x: 0.0, y: 0.0 - contentInset.top)
-    }
-}
-
-extension UISpringTimingParameters {
-    public convenience init(dampingRatio: CGFloat, frequencyResponse: CGFloat, initialVelocity: CGVector = .zero) {
-        let mass = 1 as CGFloat
-        let stiffness = pow(2 * .pi / frequencyResponse, 2) * mass
-        let damp = 4 * .pi * dampingRatio * mass / frequencyResponse
-        self.init(mass: mass, stiffness: stiffness, damping: damp, initialVelocity: initialVelocity)
-    }
-}

Framework/Tests/ViewTests.swift

@@ -1,14 +0,0 @@
-//
-//  Created by Shin Yamamoto on 2018/09/18.
-//  Copyright © 2018 Shin Yamamoto. All rights reserved.
-//
-
-import XCTest
-@testable import FloatingPanelController
-
-class ViewTests: XCTestCase {
-
-    override func setUp() {}
-
-    override func tearDown() {}
-}

LICENSE

@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2018 Shin Yamamoto
+Copyright (c) 2018-Present Shin Yamamoto
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
@@ -18,4 +18,4 @@ FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-SOFTWARE.
+SOFTWARE.

Package.swift

@@ -0,0 +1,27 @@
+// swift-tools-version:5.0
+// The swift-tools-version declares the minimum version of Swift required to build this package.
+
+import PackageDescription
+
+let package = Package(
+    name: "FloatingPanel",
+    platforms: [
+        .iOS(.v10)
+    ],
+    products: [
+        // Products define the executables and libraries produced by a package, and make them visible to other packages.
+        .library(
+            name: "FloatingPanel",
+            targets: ["FloatingPanel"]),
+    ],
+    dependencies: [
+        // Dependencies declare other packages that this package depends on.
+        // .package(url: /* package url */, from: "1.0.0"),
+    ],
+    targets: [
+        // Targets are the basic building blocks of a package. A target can define a module or a test suite.
+        // Targets can depend on other targets in this package, and on products in packages which this package depends on.
+        .target(name: "FloatingPanel", path: "Sources"),
+    ],
+    swiftLanguageVersions: [.version("5")]
+)

README.md

@@ -2,10 +2,9 @@
 [![Version](https://img.shields.io/cocoapods/v/FloatingPanel.svg)](https://cocoapods.org/pods/FloatingPanel)
 [![Carthage compatible](https://img.shields.io/badge/Carthage-compatible-4BC51D.svg?style=flat)](https://github.com/Carthage/Carthage)
 [![Platform](https://img.shields.io/cocoapods/p/FloatingPanel.svg)](https://cocoapods.org/pods/FloatingPanel)
-[![Swift 4.2](https://img.shields.io/badge/Swift-4.2-orange.svg?style=flat)](https://swift.org/)
-
-#  FloatingPanel
+[![Swift 5](https://img.shields.io/badge/Swift-5-orange.svg?style=flat)](https://swift.org/)
 
+# FloatingPanel
 
 FloatingPanel is a simple and easy-to-use UI component for a new interface introduced in Apple Maps, Shortcuts and Stocks app.
 The new interface displays the related contents and utilities in parallel as a user wants.
@@ -20,29 +19,47 @@ The new interface displays the related contents and utilities in parallel as a u
 - [Features](#features)
 - [Requirements](#requirements)
 - [Installation](#installation)
-  - [CocoaPods](#cocoapods)
-  - [Carthage](#carthage)
+    - [CocoaPods](#cocoapods)
+    - [Carthage](#carthage)
+    - [Swift Package Manager](#swift-package-manager)
 - [Getting Started](#getting-started)
-  - [Add a floating panel as a child view controller](#add-a-floating-panel-as-a-child-view-controller)
-  - [Present a floating panel as a modality](#present-a-floating-panel-as-a-modality)
+    - [Add a floating panel as a child view controller](#add-a-floating-panel-as-a-child-view-controller)
+    - [Present a floating panel as a modality](#present-a-floating-panel-as-a-modality)
 - [View hierarchy](#view-hierarchy)
 - [Usage](#usage)
-  - [Show/Hide a floating panel in a view with your view hierarchy](#showhide-a-floating-panel-in-a-view-with-your-view-hierarchy)
-  - [Customize the layout with `FloatingPanelLayout` protocol](#customize-the-layout-with-floatingpanellayout-protocol)
-    - [Change the initial position and height](#change-the-initial-position-and-height)
-    - [Support your landscape layout](#support-your-landscape-layout)
-    - [Use Intrinsic height layout](#use-intrinsic-height-layout)
-  - [Customize the behavior with `FloatingPanelBehavior` protocol](#customize-the-behavior-with-floatingpanelbehavior-protocol)
-    - [Modify your floating panel's interaction](#modify-your-floating-panels-interaction)
-  - [Use a custom grabber handle](#use-a-custom-grabber-handle)
-  - [Add tap gestures to the surface or backdrop views](#add-tap-gestures-to-the-surface-or-backdrop-views)
-  - [Create an additional floating panel for a detail](#create-an-additional-floating-panel-for-a-detail)
-  - [Move a position with an animation](#move-a-position-with-an-animation)
-  - [Work your contents together with a floating panel behavior](#work-your-contents-together-with-a-floating-panel-behavior)
+    - [Show/Hide a floating panel in a view with your view hierarchy](#showhide-a-floating-panel-in-a-view-with-your-view-hierarchy)
+    - [Scale the content view when the surface position changes](#scale-the-content-view-when-the-surface-position-changes)
+    - [Customize the layout with `FloatingPanelLayout` protocol](#customize-the-layout-with-floatingpanellayout-protocol)
+        - [Change the initial layout](#change-the-initial-layout)
+    - [Update your panel layout](#update-your-panel-layout)
+        - [Support your landscape layout](#support-your-landscape-layout)
+        - [Use the intrinsic size of a content in your panel layout](#use-the-intrinsic-size-of-a-content-in-your-panel-layout)
+        - [Specify an anchor for each state by an inset of the `FloatingPanelController.view` frame](#specify-an-anchor-for-each-state-by-an-inset-of-the-floatingpanelcontrollerview-frame)
+        - [Change the backdrop alpha](#change-the-backdrop-alpha)
+        - [Using custome panel states](#using-custome-panel-states)
+    - [Customize the behavior with `FloatingPanelBehavior` protocol](#customize-the-behavior-with-floatingpanelbehavior-protocol)
+        - [Modify your floating panel's interaction](#modify-your-floating-panels-interaction)
+        - [Activate the rubber-band effect on panel edges](#activate-the-rubber-band-effect-on-panel-edges)
+        - [Manage the projection of a pan gesture momentum](#manage-the-projection-of-a-pan-gesture-momentum)
+    - [Specify the panel move's boundary](#specify-the-panel-moves-boundary)
+    - [Customize the surface design](#customize-the-surface-design)
+        - [Modify your surface appearance](#modify-your-surface-appearance)
+        - [Use a custom grabber handle](#use-a-custom-grabber-handle)
+        - [Customize layout of the grabber handle](#customize-layout-of-the-grabber-handle)
+        - [Customize content padding from surface edges](#customize-content-padding-from-surface-edges)
+        - [Customize margins of the surface edges](#customize-margins-of-the-surface-edges)
+    - [Customize gestures](#customize-gestures)
+        - [Suppress the panel interaction](#suppress-the-panel-interaction)
+        - [Add tap gestures to the surface view](#add-tap-gestures-to-the-surface-view)
+        - [Interrupt the delegate methods of `FloatingPanelController.panGestureRecognizer`](#interrupt-the-delegate-methods-of-floatingpanelcontrollerpangesturerecognizer)
+    - [Create an additional floating panel for a detail](#create-an-additional-floating-panel-for-a-detail)
+    - [Move a position with an animation](#move-a-position-with-an-animation)
+    - [Work your contents together with a floating panel behavior](#work-your-contents-together-with-a-floating-panel-behavior)
 - [Notes](#notes)
-  - ['Show' or 'Show Detail' Segues from `FloatingPanelController`'s content view controller](#show-or-show-detail-segues-from-floatingpanelcontrollers-content-view-controller)
-  - [FloatingPanelSurfaceView's issue on iOS 10](#floatingpanelsurfaceviews-issue-on-ios-10)
-- [Author](#author)
+    - ['Show' or 'Show Detail' Segues from `FloatingPanelController`'s content view controller](#show-or-show-detail-segues-from-floatingpanelcontrollers-content-view-controller)
+    - [UISearchController issue](#uisearchcontroller-issue)
+    - [FloatingPanelSurfaceView's issue on iOS 10](#floatingpanelsurfaceviews-issue-on-ios-10)
+- [Maintainer](#maintainer)
 - [License](#license)
 
 <!-- /TOC -->
@@ -50,23 +67,32 @@ The new interface displays the related contents and utilities in parallel as a u
 ## Features
 
 - [x] Simple container view controller
-- [x] Fluid animation and gesture handling
+- [x] Fluid behavior using numeric springing
 - [x] Scroll view tracking
-- [x] Common UI elements: Grabber handle, Backdrop and Surface rounding corners
-- [x] 1~3 anchor positions(full, half, tip)
-- [x] Layout customization for all trait environments(i.e. Landscape orientation support)
-- [x] Behavior customization
-- [x] Free from common issues of Auto Layout and gesture handling
+- [x] Removal interaction
+- [x] Multi panel support
 - [x] Modal presentation
+- [x] 4 positioning support(top, left, bottom, right)
+- [x] 1 or more magnetic anchors(full, half, tip and more)
+- [x] Layout support for all trait environments(i.e. Landscape orientation)
+- [x] Common UI elements: surface, backdrop and grabber handle
+- [x] Free from common issues of Auto Layout and gesture handling
+- [x] Compatible with Objective-C
 
 Examples are here.
 
 - [Examples/Maps](https://github.com/SCENEE/FloatingPanel/tree/master/Examples/Maps) like Apple Maps.app.
 - [Examples/Stocks](https://github.com/SCENEE/FloatingPanel/tree/master/Examples/Stocks) like Apple Stocks.app.
+- [Examples/Samples](https://github.com/SCENEE/FloatingPanel/tree/master/Examples/Samples)
+- [Examples/SamplesObjC](https://github.com/SCENEE/FloatingPanel/tree/master/Examples/SamplesObjC)
 
 ## Requirements
 
-FloatingPanel is written in Swift 4.2. Compatible with iOS 10.0+
+FloatingPanel is written in Swift 5.0+. Compatible with iOS 11.0+.
+
+The deployment is still iOS 10, but it is recommended to use this library on iOS 11+.
+
+:pencil2: You would like to use Swift 4.0. Please use FloatingPanel v1. 
 
 ## Installation
 
@@ -79,6 +105,8 @@ it, simply add the following line to your Podfile:
 pod 'FloatingPanel'
 ```
 
+:pencil2: FloatingPanel v1.7.0 or later requires CocoaPods v1.7.0+ for `swift_versions` support.
+
 ### Carthage
 
 For [Carthage](https://github.com/Carthage/Carthage), add the following to your `Cartfile`:
@@ -87,6 +115,10 @@ For [Carthage](https://github.com/Carthage/Carthage), add the following to your
 github "scenee/FloatingPanel"
 ```
 
+### Swift Package Manager
+
+Follow [this doc](https://developer.apple.com/documentation/swift_packages/adding_package_dependencies_to_your_app).
+
 ## Getting Started
 
 ### Add a floating panel as a child view controller
@@ -116,13 +148,6 @@ class ViewController: UIViewController, FloatingPanelControllerDelegate {
         // Add and show the views managed by the `FloatingPanelController` object to self.view.
         fpc.addPanel(toParent: self)
     }
-
-    override func viewWillDisappear(_ animated: Bool) {
-        super.viewWillDisappear(animated)
-
-        // Remove the views managed by the `FloatingPanelController` object from self.view.
-        fpc.removePanelFromParent()
-    }
 }
 ```
 
@@ -138,9 +163,9 @@ fpc.isRemovalInteractionEnabled = true // Optional: Let it removable by a swipe-
 self.present(fpc, animated: true, completion: nil)
 ```
 
-You can show a floating panel over UINavigationController from the containnee view controllers as a modality of `.overCurrentContext` style.
+You can show a floating panel over UINavigationController from the container view controllers as a modality of `.overCurrentContext` style.
 
-NOTE: FloatingPanelController has the custom presentation controller. If you would like to customize the presentation/dismissal, please see [FloatingPanelTransitioning](https://github.com/SCENEE/FloatingPanel/blob/feat-modality/Framework/Sources/FloatingPanelTransitioning.swift).
+:pencil2: FloatingPanelController has the custom presentation controller. If you would like to customize the presentation/dismissal, please see [Transitioning](https://github.com/SCENEE/FloatingPanel/blob/master/Sources/Transitioning.swift).
 
 ## View hierarchy
 
@@ -150,75 +175,131 @@ NOTE: FloatingPanelController has the custom presentation controller. If you wou
 FloatingPanelController.view (FloatingPanelPassThroughView)
  ├─ .backdropView (FloatingPanelBackdropView)
  └─ .surfaceView (FloatingPanelSurfaceView)
-          ├─ .contentView  == FloatingPanelController.contentViewController.view
-          └─ .grabberHandle (GrabberHandleView)
+    ├─ .containerView (UIView)
+    │  └─ .contentView (FloatingPanelController.contentViewController.view)
+    └─ .grabber (FloatingPanelGrabberView)
 ```
 
 ## Usage
 
 ### Show/Hide a floating panel in a view with your view hierarchy
 
+If you need more control over showing and hiding the floating panel, you can forgo the `addPanel` and `removePanelFromParent` methods. These methods are a convenience wrapper for **FloatingPanel**'s `show` and `hide` methods along with some required setup.
+
+There are two ways to work with the `FloatingPanelController`:
+1. Add it to the hierarchy once and then call `show` and `hide` methods to make it appear/disappear.
+2. Add it to the hierarchy when needed and remove afterwards.
+
+The following example shows how to add the controller to your `UIViewController` and how to remove it. Make sure that you never add the same `FloatingPanelController` to the hierarchy before removing it.
+
+**NOTE**: `self.` prefix is not required, nor recommended. It's used here to make it clearer where do the functions used come from. `self` is an instance of a custom UIViewController in your code.
+
 ```swift
-// Add the controller and the managed views to a view controller.
-// From the second time, just call `show(animated:completion)`.
-view.addSubview(fpc.view)
+// Add the floating panel view to the controller's view on top of other views.
+self.view.addSubview(fpc.view)
+
+// REQUIRED. It makes the floating panel view have the same size as the controller's view.
+fpc.view.frame = self.view.bounds
 
-fpc.view.frame = view.bounds // MUST
 // In addition, Auto Layout constraints are highly recommended.
-// Because it makes the layout more robust on trait collection change.
-//
-//     fpc.view.translatesAutoresizingMaskIntoConstraints = false
-//     NSLayoutConstraint.activate([...])
-// 
+// Constraint the fpc.view to all four edges of your controller's view.
+// It makes the layout more robust on trait collection change.
+fpc.view.translatesAutoresizingMaskIntoConstraints = false
+NSLayoutConstraint.activate([
+  fpc.view.topAnchor.constraint(equalTo: self.view.topAnchor, constant: 0.0),
+  fpc.view.leftAnchor.constraint(equalTo: self.view.leftAnchor, constant: 0.0),
+  fpc.view.rightAnchor.constraint(equalTo: self.view.rightAnchor, constant: 0.0),
+  fpc.view.bottomAnchor.constraint(equalTo: self.view.bottomAnchor, constant: 0.0),
+])
 
-parent.addChild(fpc)
+// Add the floating panel controller to the controller hierarchy.
+self.addChild(fpc)
 
-// Show a floating panel to the initial position defined in your `FloatingPanelLayout` object.
+// Show the floating panel at the initial position defined in your `FloatingPanelLayout` object.
 fpc.show(animated: true) {
-
-    // Only for the first time
-    self.didMove(toParent: self)
-}
-
-...
-
-// Hide it
-fpc.hide(animated: true) {
-
-    // Remove it if needed
-    self.willMove(toParent: nil)
-    self.view.removeFromSuperview()
-    self.removeFromParent()
+    // Inform the floating panel controller that the transition to the controller hierarchy has completed.
+    fpc.didMove(toParent: self)
 }
 ```
 
-NOTE: `FloatingPanelController` wraps `show`/`hide` with `addPanel`/`removePanelFromParent` for easy-to-use. But `show`/`hide` are more convenience for your app.
+After you add the `FloatingPanelController` as seen above, you can call `fpc.show(animated: true) { }` to show the panel and `fpc.hide(animated: true) { }` to hide it.
+
+To remove the `FloatingPanelController` from the hierarchy, follow the example below.
+
+```swift
+// Inform the panel controller that it will be removed from the hierarchy.
+fpc.willMove(toParent: nil)
+    
+// Hide the floating panel.
+fpc.hide(animated: true) {
+    // Remove the floating panel view from your controller's view.
+    fpc.view.removeFromSuperview()
+    // Remove the floating panel controller from the controller hierarchy.
+    fpc.removeFromParent()
+}
+```
+
+### Scale the content view when the surface position changes
+
+Specify the `contentMode` to `.fitToBounds` if the surface height fits the bounds of `FloatingPanelController.view` when the surface position changes
+
+```swift
+fpc.contentMode = .fitToBounds
+```
+
+Otherwise, `FloatingPanelController` fixes the content by the height of the top most position.
+
+:pencil2: In `.fitToBounds` mode, the surface height changes as following a user interaction so that you have a responsibility to configure Auto Layout constrains not to break the layout of a content view by the elastic surface height.
 
 ### Customize the layout with `FloatingPanelLayout` protocol
 
-#### Change the initial position and height
+#### Change the initial layout
 
 ```swift
 class ViewController: UIViewController, FloatingPanelControllerDelegate {
-    ...
-    func floatingPanel(_ vc: FloatingPanelController, layoutFor newCollection: UITraitCollection) -> FloatingPanelLayout? {
-        return MyFloatingPanelLayout()
+    ... {
+        fpc = FloatingPanelController(delegate: self)
+        fpc.layout = MyFloatingPanelLayout()
     }
 }
 
 class MyFloatingPanelLayout: FloatingPanelLayout {
-    public var initialPosition: FloatingPanelPosition {
-        return .tip
+    let position: FloatingPanelPosition = .bottom
+    let initialState: FloatingPanelState = .tip
+    var anchors: [FloatingPanelState: FloatingPanelLayoutAnchoring] {
+        return [
+            .full: FloatingPanelLayoutAnchor(absoluteInset: 16.0, edge: .top, referenceGuide: .safeArea),
+            .half: FloatingPanelLayoutAnchor(fractionalInset: 0.5, edge: .bottom, referenceGuide: .safeArea),
+            .tip: FloatingPanelLayoutAnchor(absoluteInset: 44.0, edge: .bottom, referenceGuide: .safeArea),
+        ]
+    }
+}
+```
+
+### Update your panel layout
+
+There are 2 ways to update the panel layout.
+
+1. Manually set `FloatingPanelController.layout` to the new layout object directly.
+
+```swift
+fpc.layout = MyPanelLayout()
+fpc.invalidateLayout() // If needed
+```
+
+2. Returns an appropriate layout object in one of 2 `floatingPanel(_:layoutFor:)` delegates.
+
+```swift
+class ViewController: UIViewController, FloatingPanelControllerDelegate {
+    ...
+    func floatingPanel(_ vc: FloatingPanelController, layoutFor newCollection: UITraitCollection) -> FloatingPanelLayout {
+        return MyFloatingPanelLayout()
     }
 
-    public func insetFor(position: FloatingPanelPosition) -> CGFloat? {
-        switch position {
-            case .full: return 16.0 // A top inset from safe area
-            case .half: return 216.0 // A bottom inset from the safe area
-            case .tip: return 44.0 // A bottom inset from the safe area
-            default: return nil // Or `case .hidden: return nil`
-        }
-    }
+    // OR
+    func floatingPanel(_ vc: FloatingPanelController, layoutFor size: CGSize) -> FloatingPanelLayout {
+        return MyFloatingPanelLayout()
+    } 
 }
 ```
 
@@ -227,60 +308,107 @@ class MyFloatingPanelLayout: FloatingPanelLayout {
 ```swift
 class ViewController: UIViewController, FloatingPanelControllerDelegate {
     ...
-    func floatingPanel(_ vc: FloatingPanelController, layoutFor newCollection: UITraitCollection) -> FloatingPanelLayout? {
-        return (newCollection.verticalSizeClass == .compact) ? FloatingPanelLandscapeLayout() : nil // Returning nil indicates to use the default layout
+    func floatingPanel(_ vc: FloatingPanelController, layoutFor newCollection: UITraitCollection) -> FloatingPanelLayout {
+        return (newCollection.verticalSizeClass == .compact) ? LandscapePanelLayout() : FloatingPanelBottomLayout()
     }
 }
 
-class FloatingPanelLandscapeLayout: FloatingPanelLayout {
-    public var initialPosition: FloatingPanelPosition {
-        return .tip
-    }
-    public var supportedPositions: Set<FloatingPanelPosition> {
-        return [.full, .tip]
-    }
-
-    public func insetFor(position: FloatingPanelPosition) -> CGFloat? {
-        switch position {
-            case .full: return 16.0
-            case .tip: return 69.0
-            default: return nil
-        }
-    }
-
-    public func prepareLayout(surfaceView: UIView, in view: UIView) -> [NSLayoutConstraint] {
+class LandscapePanelLayout: FloatingPanelLayout {
+    let position: FloatingPanelPosition = .bottom
+    let initialState: FloatingPanelState = .tip
+    var anchors: [FloatingPanelState: FloatingPanelLayoutAnchoring] {
         return [
-            surfaceView.leftAnchor.constraint(equalTo: view.safeAreaLayoutGuid.leftAnchor, constant: 8.0),
+            .full: FloatingPanelLayoutAnchor(absoluteInset: 16.0, edge: .top, referenceGuide: .safeArea),
+            .tip: FloatingPanelLayoutAnchor(absoluteInset: 69.0, edge: .bottom, referenceGuide: .safeArea),
+        ]
+    }
+    func prepareLayout(surfaceView: UIView, in view: UIView) -> [NSLayoutConstraint] {
+        return [
+            surfaceView.leftAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leftAnchor, constant: 8.0),
             surfaceView.widthAnchor.constraint(equalToConstant: 291),
         ]
     }
 }
 ```
 
-#### Use Intrinsic height layout
+#### Use the intrinsic size of a content in your panel layout
 
 1. Lay out your content View with the intrinsic height size. For example, see "Detail View Controller scene"/"Intrinsic View Controller scene" of [Main.storyboard](https://github.com/SCENEE/FloatingPanel/blob/master/Examples/Samples/Sources/Base.lproj/Main.storyboard). The 'Stack View.bottom' constraint determines the intrinsic height.
-2. Create a layout that adopts and conforms to `FloatingPanelIntrinsicLayout` and use it.
+2. Specify layout anchors using `FloatingPanelIntrinsicLayoutAnchor`.
 
 ```swift
-class ViewController: UIViewController, FloatingPanelControllerDelegate {
+class IntrinsicPanelLayout: FloatingPanelLayout {
+    let position: FloatingPanelPosition = .bottom
+    let initialState: FloatingPanelState = .full
+    var anchors: [FloatingPanelState: FloatingPanelLayoutAnchoring] {
+        return [
+            .full: FloatingPanelIntrinsicLayoutAnchor(absoluteOffset: 0, referenceGuide: .safeArea),
+            .half: FloatingPanelIntrinsicLayoutAnchor(fractionalOffset: 0.5, referenceGuide: .safeArea),
+        ]
+    }
     ...
-    func floatingPanel(_ vc: FloatingPanelController, layoutFor newCollection: UITraitCollection) -> FloatingPanelLayout? {
-        return RemovablePanelLayout()
+}
+```
+
+:pencil2: `FloatingPanelIntrinsicLayout` is deprecated on v1.
+
+#### Specify an anchor for each state by an inset of the `FloatingPanelController.view` frame
+
+Use `.superview` reference guide in your anchors.
+
+```swift
+class MyFullScreenLayout: FloatingPanelLayout {
+    ...
+    var anchors: [FloatingPanelState: FloatingPanelLayoutAnchoring] {
+        return [
+            .full: FloatingPanelLayoutAnchor(absoluteInset: 16.0, edge: .top, referenceGuide: .superview),
+            .half: FloatingPanelLayoutAnchor(fractionalInset: 0.5, edge: .bottom, referenceGuide: .superview),
+            .tip: FloatingPanelLayoutAnchor(absoluteInset: 44.0, edge: .bottom, referenceGuide: .superview),
+        ]
+
     }
 }
+```
 
-class RemovablePanelLayout: FloatingPanelIntrinsicLayout {
-    var supportedPositions: Set<FloatingPanelPosition> {
-        return [.full, .half]
-    }
-    func insetFor(position: FloatingPanelPosition) -> CGFloat? {
-        switch position {
-        case .half: return 130.0
-        default: return nil  // Must return nil for .full
+:pencil2: `FloatingPanelFullScreenLayout` is deprecated on v1.
+
+#### Change the backdrop alpha
+
+You can change the backdrop alpha by `FloatingPanelLayout.backdropAlpha(for:)` for each state(`.full`, `.half` and `.tip`).
+
+For instance, if a panel seems like the backdrop view isn't there on `.half` state, it's time to implement the backdropAlpha API and return a value for the state as below.
+
+```swift
+class MyPanelLayout: FloatingPanelLayout {
+    func backdropAlpha(for state: FloatingPanelState) -> CGFloat {
+        switch state {
+        case .full, .half: return 0.3
+        default: return 0.0
         }
     }
-    ...
+}
+```
+
+#### Using custome panel states
+
+You're able to define custom panel states and use them as the following example.
+
+```swift
+extension FloatingPanelState {
+    static let lastQuart: FloatingPanelState = FloatingPanelState(rawValue: "lastQuart", order: 750)
+    static let firstQuart: FloatingPanelState = FloatingPanelState(rawValue: "firstQuart", order: 250)
+}
+
+class FloatingPanelLayoutWithCustomState: FloatingPanelBottomLayout {
+    override var anchors: [FloatingPanelState: FloatingPanelLayoutAnchoring] {
+        return [
+            .full: FloatingPanelLayoutAnchor(absoluteInset: 0.0, edge: .top, referenceGuide: .safeArea),
+            .lastQuart: FloatingPanelLayoutAnchor(fractionalInset: 0.75, edge: .bottom, referenceGuide: .safeArea),
+            .half: FloatingPanelLayoutAnchor(fractionalInset: 0.5, edge: .bottom, referenceGuide: .safeArea),
+            .firstQuart: FloatingPanelLayoutAnchor(fractionalInset: 0.25, edge: .bottom, referenceGuide: .safeArea),
+            .tip: FloatingPanelLayoutAnchor(absoluteInset: 20.0, edge: .bottom, referenceGuide: .safeArea),
+        ]
+    }
 }
 ```
 
@@ -291,22 +419,90 @@ class RemovablePanelLayout: FloatingPanelIntrinsicLayout {
 ```swift
 class ViewController: UIViewController, FloatingPanelControllerDelegate {
     ...
-    func floatingPanel(_ vc: FloatingPanelController, behaviorFor newCollection: UITraitCollection) -> FloatingPanelBehavior? {
-        return FloatingPanelStocksBehavior()
+    func viewDidLoad() {
+        ...
+        fpc.behavior =  CustomPanelBehavior()
     }
 }
 
-class FloatingPanelStocksBehavior: FloatingPanelBehavior {
-    ...
-    func interactionAnimator(_ fpc: FloatingPanelController, to targetPosition: FloatingPanelPosition, with velocity: CGVector) -> UIViewPropertyAnimator {
-        let damping = self.damping(with: velocity)
-        let springTiming = UISpringTimingParameters(dampingRatio: damping, initialVelocity: velocity)
-        return UIViewPropertyAnimator(duration: 0.5, timingParameters: springTiming)
+class CustomPanelBehavior: FloatingPanelBehavior {
+    let springDecelerationRate = UIScrollView.DecelerationRate.fast.rawValue + 0.02
+    let springResponseTime = 0.4
+    func shouldProjectMomentum(_ fpc: FloatingPanelController, to proposedTargetPosition: FloatingPanelState) -> Bool {
+        return true
     }
 }
 ```
 
-### Use a custom grabber handle
+:pencil2: `floatingPanel(_ vc:behaviorFor:)` is deprecated on v1.
+
+#### Activate the rubber-band effect on panel edges
+
+```swift
+class MyPanelBehavior: FloatingPanelBehavior {
+    ...
+    func allowsRubberBanding(for edge: UIRectEdge) -> Bool {
+        return true
+    }
+}
+```
+
+#### Manage the projection of a pan gesture momentum
+
+This allows full projectional panel behavior. For example, a user can swipe up a panel from tip to full nearby the tip position.
+
+```swift
+class MyPanelBehavior: FloatingPanelBehavior {
+    ...
+    func shouldProjectMomentum(_ fpc: FloatingPanelController, to proposedTargetPosition: FloatingPanelPosition) -> Bool {
+        return true
+    }
+}
+```
+
+### Specify the panel move's boundary
+
+`FloatingPanelController.surfaceLocation` in `floatingPanelDidMove(_:)` delegate method behaves like `UIScrollView.contentOffset` in `scrollViewDidScroll(_:)`.
+As a result, you can specify the boundary of a panel move as below.
+
+```swift
+func floatingPanelDidMove(_ vc: FloatingPanelController) {
+    if vc.isAttracting == false {
+        let loc = vc.surfaceLocation
+        let minY = vc.surfaceLocation(for: .full).y - 6.0
+        let maxY = vc.surfaceLocation(for: .tip).y + 6.0
+        vc.surfaceLocation = CGPoint(x: loc.x, y: min(max(loc.y, minY), maxY))
+    }
+}
+```
+
+:pencil2: `{top,bottom}InteractionBuffer` property is removed from `FloatingPanelLayout` since v2.
+
+### Customize the surface design
+
+#### Modify your surface appearance
+
+```swift
+// Create a new appearance.
+let appearance = SurfaceAppearance()
+
+// Define shadows
+let shadow = SurfaceAppearance.Shadow()
+shadow.color = UIColor.black
+shadow.offset = CGSize(width: 0, height: 16)
+shadow.radius = 16
+shadow.spread = 8
+appearance.shadows = [shadow]
+
+// Define corner radius and background color
+appearance.cornerRadius = 8.0
+appearance.backgroundColor = .clear
+
+// Set the new appearance
+fpc.surfaceView.appearance = appearance
+````
+
+#### Use a custom grabber handle
 
 ```swift
 let myGrabberHandleView = MyGrabberHandleView()
@@ -314,17 +510,57 @@ fpc.surfaceView.grabberHandle.isHidden = true
 fpc.surfaceView.addSubview(myGrabberHandleView)
 ```
 
-### Add tap gestures to the surface or backdrop views
+#### Customize layout of the grabber handle
+
+```swift
+fpc.surfaceView.grabberHandlePadding = 10.0
+fpc.surfaceView.grabberHandleSize = .init(width: 44.0, height: 12.0)
+```
+
+:pencil2: Note that `grabberHandleSize` width and height are reversed in the left/right position.
+
+#### Customize content padding from surface edges
+
+```swift
+fpc.surfaceView.contentPadding = .init(top: 20, left: 20, bottom: 20, right: 20)
+```
+
+#### Customize margins of the surface edges
+
+```swift
+fpc.surfaceView.containerMargins = .init(top: 20.0, left: 16.0, bottom: 16.0, right: 16.0)
+```
+
+The feature can be used for these 2 kind panels
+
+* Facebook/Slack-like panel whose surface top edge is separated from the grabber handle.
+* iOS native panel to display AirPods information, for example.
+
+### Customize gestures
+
+#### Suppress the panel interaction
+
+You can disable the pan gesture recognizer directly
+
+```swift
+fpc.panGestureRecognizer.isEnabled = false
+```
+
+Or use this `FloatingPanelControllerDelegate` method.
+
+```swift
+func floatingPanelShouldBeginDragging(_ vc: FloatingPanelController) -> Bool {
+    return aCondition ?  false : true
+}
+```
+
+#### Add tap gestures to the surface view
 
 ```swift
 override func viewDidLoad() {
     ...
-    surfaceTapGesture = UITapGestureRecognizer(target: self, action: #selector(handleSurface(tapGesture:)))
+    let surfaceTapGesture = UITapGestureRecognizer(target: self, action: #selector(handleSurface(tapGesture:)))
     fpc.surfaceView.addGestureRecognizer(surfaceTapGesture)
-
-    backdropTapGesture = UITapGestureRecognizer(target: self, action: #selector(handleBackdrop(tapGesture:)))
-    fpc.backdropView.addGestureRecognizer(backdropTapGesture)
-
     surfaceTapGesture.isEnabled = (fpc.position == .tip)
 }
 
@@ -334,6 +570,26 @@ func floatingPanelDidChangePosition(_ vc: FloatingPanelController) {
 }
 ```
 
+#### Interrupt the delegate methods of `FloatingPanelController.panGestureRecognizer`
+
+If you are set `FloatingPanelController.panGestureRecognizer.delegateProxy` to an object adopting `UIGestureRecognizerDelegate`, it overrides delegate methods of the pan gesture recognizer.
+
+```swift
+class MyGestureRecognizerDelegate: UIGestureRecognizerDelegate {
+    func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRequireFailureOf otherGestureRecognizer: UIGestureRecognizer) -> Bool {
+        return false
+    }
+}
+
+class ViewController: UIViewController {
+    let myGestureDelegate = MyGestureRecognizerDelegate()
+
+    func setUpFpc() {
+        ....
+        fpc.panGestureRecognizer.delegateProxy = myGestureDelegate
+    }
+```
+
 ### Create an additional floating panel for a detail
 
 ```swift
@@ -374,6 +630,14 @@ func searchBarTextDidBeginEditing(_ searchBar: UISearchBar) {
 }
 ```
 
+You can also use a view animation to move a panel.
+
+```swift
+UIView.animate(withDuration: 0.25) {
+    self.fpc.move(to: .half, animated: false)
+}
+```
+
 ### Work your contents together with a floating panel behavior
 
 ```swift
@@ -386,8 +650,8 @@ class ViewController: UIViewController, FloatingPanelControllerDelegate {
         }
     }
 
-    func floatingPanelDidEndDragging(_ vc: FloatingPanelController, withVelocity velocity: CGPoint, targetPosition: FloatingPanelPosition) {
-        if targetPosition != .full {
+    func floatingPanelWillEndDragging(_ vc: FloatingPanelController, withVelocity velocity: CGPoint, targetState: UnsafeMutablePointer<FloatingPanelState>) {
+        if targetState.pointee != .full {
             searchVC.hideHeader()
         }
     }
@@ -428,6 +692,12 @@ A `FloatingPanelController` object proxies an action for `show(_:sender)` to the
 
 It's a great way to decouple between a floating panel and the content VC.
 
+### UISearchController issue
+
+`UISearchController` isn't able to be used with `FloatingPanelController` by the system design.
+
+Because `UISearchController` automatically presents itself modally when a user interacts with the search bar, and then it swaps the superview of the search bar to the view managed by itself while it displays. As a result, `FloatingPanelController` can't control the search bar when it's active, as you can see from [the screen shot](https://github.com/SCENEE/FloatingPanel/issues/248#issuecomment-521263831).
+
 ### FloatingPanelSurfaceView's issue on iOS 10
 
 * On iOS 10, `FloatingPanelSurfaceView.cornerRadius` isn't not automatically masked with the top rounded corners  because of `UIVisualEffectView` issue. See https://forums.developer.apple.com/thread/50854. 
@@ -443,7 +713,7 @@ override func viewDidLayoutSubviews() {
 ```
 * If you sets clear color to `FloatingPanelSurfaceView.backgroundColor`, please note the bottom overflow of your content on bouncing at full position. To prevent it, you need to expand your content. For example, See Example/Maps App's Auto Layout settings of `UIVisualEffectView` in Main.storyboard.
 
-## Author
+## Maintainer
 
 Shin Yamamoto <shin@scenee.com> | [@scenee](https://twitter.com/scenee)
 

Sources/BackdropView.swift

@@ -0,0 +1,11 @@
+// Copyright 2018-Present Shin Yamamoto. All rights reserved. MIT license.
+
+import UIKit
+
+/// A view that presents a backdrop interface behind a panel.
+@objc(FloatingPanelBackdropView)
+public class BackdropView: UIView {
+
+    /// The gesture recognizer for tap gestures to dismiss a panel.
+    public var dismissalTapGestureRecognizer: UITapGestureRecognizer!
+}

Sources/Behavior.swift

@@ -0,0 +1,126 @@
+// Copyright 2018-Present Shin Yamamoto. All rights reserved. MIT license.
+
+import UIKit
+
+/// An interface for generating behavior information to fine-tune the behavior of a panel.
+@objc
+public protocol FloatingPanelBehavior {
+    /// A floating-point value that determines the rate of oscillation magnitude reduction after the user lifts their finger.
+    ///
+    /// The oscillation magnitude to attract a panel to an anchor can be adjusted this value between 0.979 and 1.0
+    /// in increments of 0.001. When this value is around 0.979, the attraction uses a critically damped spring system.
+    /// When this value is between 0.978 and 1.0, it uses a underdamped spring system with a damping ratio computed by
+    /// this value. You shouldn't return less than 0.979 because the system is overdamped. If the pan gesture's velocity
+    /// is less than 300, this value is ignored and a panel applies a critically damped system.
+    @objc optional
+    var springDecelerationRate: CGFloat { get }
+
+    /// A floating-point value that determines the approximate time until a panel stops to an anchor after the user lifts their finger.
+    @objc optional
+    var springResponseTime: CGFloat { get }
+
+    /// Returns a deceleration rate to calculate a target position projected a dragging momentum.
+    ///
+    /// The default implementation of this method returns the normal deceleration rate of UIScrollView.
+    @objc optional
+    var momentumProjectionRate: CGFloat { get }
+
+    /// Asks the behavior if a panel should project a momentum of a user interaction to move the proposed position.
+    ///
+    /// The default implementation of this method returns true. This method is called for a layout to support all positions(tip, half and full).
+    /// Therefore, `proposedTargetPosition` can only be `FloatingPanelState.tip` or `FloatingPanelState.full`.
+    @objc optional
+    func shouldProjectMomentum(_ fpc: FloatingPanelController, to proposedTargetPosition: FloatingPanelState) -> Bool
+
+    /// Returns the progress to redirect to the previous position.
+    ///
+    /// The progress is represented by a floating-point value between 0.0 and 1.0, inclusive, where 1.0 indicates a panel is impossible to move to the next position. The default value is 0.5. Values less than 0.0 and greater than 1.0 are pinned to those limits.
+    @objc optional
+    func redirectionalProgress(_ fpc: FloatingPanelController, from: FloatingPanelState, to: FloatingPanelState) -> CGFloat
+
+    /// Asks the behavior whether the rubber band effect is enabled in moving over a given edge of the surface view.
+    ///
+    /// This method allows a panel to activate the rubber band effect to a given edge of the surface view. By default, the effect is disabled.
+    @objc optional
+    func allowsRubberBanding(for edge: UIRectEdge) -> Bool
+    
+    /// Returns the velocity threshold for the default interactive removal gesture.
+    ///
+    /// In case `floatingPanel:shouldRemoveAt:with` is implemented, this value will not be used. The default value of `FloatingPanelDefaultBehavior` is 5.5
+    @objc optional
+    var removalInteractionVelocityThreshold: CGFloat { get }
+}
+
+/// The default behavior object for a panel
+///
+/// This behavior object is fine-tuned to behave as a search panel(card) in Apple Maps on iPhone portrait orientation.
+open class FloatingPanelDefaultBehavior: FloatingPanelBehavior {
+    public init() {}
+
+    open var springDecelerationRate: CGFloat {
+        return UIScrollView.DecelerationRate.fast.rawValue + 0.001
+    }
+
+    open var springResponseTime: CGFloat {
+        return 0.4
+    }
+
+    open var momentumProjectionRate: CGFloat {
+        return UIScrollView.DecelerationRate.normal.rawValue
+    }
+
+    open func redirectionalProgress(_ fpc: FloatingPanelController, from: FloatingPanelState, to: FloatingPanelState) -> CGFloat {
+        return 0.5
+    }
+
+    open func allowsRubberBanding(for edge: UIRectEdge) -> Bool {
+        return false
+    }
+    
+    open var removalInteractionVelocityThreshold: CGFloat = 5.5
+}
+
+class BehaviorAdapter {
+    unowned let vc: FloatingPanelController
+    fileprivate var behavior: FloatingPanelBehavior
+
+    init(vc: FloatingPanelController, behavior: FloatingPanelBehavior) {
+        self.vc = vc
+        self.behavior = behavior
+    }
+
+    var springDecelerationRate: CGFloat {
+        behavior.springDecelerationRate ?? FloatingPanelDefaultBehavior().springDecelerationRate
+    }
+
+    var springResponseTime: CGFloat {
+        behavior.springResponseTime ?? FloatingPanelDefaultBehavior().springResponseTime
+    }
+
+    var momentumProjectionRate: CGFloat {
+        behavior.momentumProjectionRate ?? FloatingPanelDefaultBehavior().momentumProjectionRate
+    }
+    
+    var removalInteractionVelocityThreshold: CGFloat {
+        behavior.removalInteractionVelocityThreshold ?? FloatingPanelDefaultBehavior().removalInteractionVelocityThreshold
+    }
+
+    func redirectionalProgress(from: FloatingPanelState, to: FloatingPanelState) -> CGFloat {
+        behavior.redirectionalProgress?(vc, from: from, to: to) ?? FloatingPanelDefaultBehavior().redirectionalProgress(vc,from: from, to: to)
+    }
+
+    func shouldProjectMomentum(to: FloatingPanelState) -> Bool {
+        behavior.shouldProjectMomentum?(vc, to: to) ?? false
+    }
+
+    func allowsRubberBanding(for edge: UIRectEdge) -> Bool {
+        behavior.allowsRubberBanding?(for: edge) ?? false
+    }
+}
+
+extension FloatingPanelController {
+    var _behavior: FloatingPanelBehavior {
+        get { floatingPanel.behaviorAdapter.behavior }
+        set { floatingPanel.behaviorAdapter.behavior = newValue}
+    }
+}

Sources/Controller.swift

@@ -0,0 +1,717 @@
+// Copyright 2018-Present Shin Yamamoto. All rights reserved. MIT license.
+
+import UIKit
+
+/// A set of methods implemented by the delegate of a panel controller allows the adopting delegate to respond to
+/// messages from the FloatingPanelController class and thus respond to, and in some affect, operations such as
+/// dragging, attracting a panel, layout of a panel and the content, and transition animations.
+@objc public protocol FloatingPanelControllerDelegate {
+    /// Returns a FloatingPanelLayout object. If you use the default one, you can use a `FloatingPanelBottomLayout` object.
+    @objc(floatingPanel:layoutForTraitCollection:) optional
+    func floatingPanel(_ fpc: FloatingPanelController, layoutFor newCollection: UITraitCollection) -> FloatingPanelLayout
+
+    /// Returns a FloatingPanelLayout object. If you use the default one, you can use a `FloatingPanelBottomLayout` object.
+    @objc(floatingPanel:layoutForSize:) optional
+    func floatingPanel(_ fpc: FloatingPanelController, layoutFor size: CGSize) -> FloatingPanelLayout
+
+    /// Returns a UIViewPropertyAnimator object to add/present the  panel to a position.
+    ///
+    /// Default is the spring animation with 0.25 secs.
+    @objc(floatingPanel:animatorForPresentingToState:) optional
+    func floatingPanel(_ fpc: FloatingPanelController, animatorForPresentingTo state: FloatingPanelState) -> UIViewPropertyAnimator
+
+    /// Returns a UIViewPropertyAnimator object to remove/dismiss a panel from a position.
+    ///
+    /// Default is the spring animator with 0.25 secs.
+    @objc(floatingPanel:animatorForDismissingWithVelocity:) optional
+    func floatingPanel(_ fpc: FloatingPanelController, animatorForDismissingWith velocity: CGVector) -> UIViewPropertyAnimator
+
+    /// Called when a panel has changed to a new position. Can be called inside an animation block, so any
+    /// view properties set inside this function will be automatically animated alongside a panel.
+    @objc optional
+    func floatingPanelDidChangePosition(_ fpc: FloatingPanelController)
+
+    /// Asks the delegate if dragging should begin by the pan gesture recognizer.
+    @objc optional
+    func floatingPanelShouldBeginDragging(_ fpc: FloatingPanelController) -> Bool
+
+    /// Called when the user drags the surface or the surface is attracted to a state anchor.
+    @objc optional
+    func floatingPanelDidMove(_ fpc: FloatingPanelController) // any surface frame changes in dragging
+
+    /// Called on start of dragging (may require some time and or distance to move)
+    @objc optional
+    func floatingPanelWillBeginDragging(_ fpc: FloatingPanelController)
+
+    /// Called on finger up if the user dragged. velocity is in points/second.
+    @objc optional
+    func floatingPanelWillEndDragging(_ fpc: FloatingPanelController, withVelocity velocity: CGPoint, targetState: UnsafeMutablePointer<FloatingPanelState>)
+
+    /// Called on finger up if the user dragged.
+    ///
+    /// If `attract` is true, it will continue moving afterwards to a nearby state anchor.
+    @objc optional
+    func floatingPanelDidEndDragging(_ fpc: FloatingPanelController, willAttract attract: Bool)
+
+    /// Called when it is about to be attracted to a state anchor.
+    @objc optional
+    func floatingPanelWillBeginAttracting(_ fpc: FloatingPanelController, to state: FloatingPanelState) // called on finger up as a panel are moving
+
+    /// Called when attracting it is completed.
+    @objc optional
+    func floatingPanelDidEndAttracting(_ fpc: FloatingPanelController) // called when a panel stops
+
+    /// Asks the delegate whether a panel should be removed when dragging ended at the specified location
+    ///
+    /// This delegate method is called only where `FloatingPanelController.isRemovalInteractionEnabled` is `true`.
+    /// The velocity vector is calculated from the distance to a point of the hidden state and the pan gesture's velocity.
+    @objc(floatingPanel:shouldRemoveAtLocation:withVelocity:)
+    optional
+    func floatingPanel(_ fpc: FloatingPanelController, shouldRemoveAt location: CGPoint, with velocity: CGVector) -> Bool
+
+    /// Called on start to remove its view controller from the parent view controller.
+    @objc(floatingPanelWillRemove:)
+    optional
+    func floatingPanelWillRemove(_ fpc: FloatingPanelController)
+
+    /// Called when a panel is removed from the parent view controller.
+    @objc optional
+    func floatingPanelDidRemove(_ fpc: FloatingPanelController)
+
+    /// Asks the delegate for a content offset of the tracking scroll view to be pinned when a panel moves
+    ///
+    /// If you do not implement this method, the controller uses a value of the content offset plus the content insets
+    /// of the tracked scroll view. Your implementation of this method can return a value for a navigation bar with a large
+    /// title, for example.
+    ///
+    /// This method will not be called if the controller doesn't track any scroll view.
+    @objc(floatingPanel:contentOffsetForPinningScrollView:)
+    optional
+    func floatingPanel(_ fpc: FloatingPanelController, contentOffsetForPinning trackingScrollView: UIScrollView) -> CGPoint
+}
+
+///
+/// A container view controller to display a panel to present contents in parallel as a user wants.
+///
+@objc
+open class FloatingPanelController: UIViewController {
+    /// Constants indicating how safe area insets are added to the adjusted content inset.
+    @objc
+    public enum ContentInsetAdjustmentBehavior: Int {
+        case always
+        case never
+    }
+
+    /// A flag used to determine how the controller object lays out the content view when the surface position changes.
+    @objc
+    public enum ContentMode: Int {
+        /// The option to fix the content to keep the height of the top most position.
+        case `static`
+        /// The option to scale the content to fit the bounds of the root view by changing the surface position.
+        case fitToBounds
+    }
+
+    /// The delegate of a panel controller object.
+    @objc 
+    public weak var delegate: FloatingPanelControllerDelegate?{
+        didSet{
+            didUpdateDelegate()
+        }
+    }
+
+    /// Returns the surface view managed by the controller object. It's the same as `self.view`.
+    @objc
+    public var surfaceView: SurfaceView! {
+        return floatingPanel.surfaceView
+    }
+
+    /// Returns the backdrop view managed by the controller object.
+    @objc
+    public var backdropView: BackdropView! {
+        return floatingPanel.backdropView
+    }
+
+    /// Returns the scroll view that the controller tracks.
+    @objc
+    public weak var trackingScrollView: UIScrollView? {
+        return floatingPanel.scrollView
+    }
+
+    // The underlying gesture recognizer for pan gestures
+    @objc
+    public var panGestureRecognizer: FloatingPanelPanGestureRecognizer {
+        return floatingPanel.panGestureRecognizer
+    }
+
+    /// The current position of a panel controller's contents.
+    @objc
+    public var state: FloatingPanelState {
+        return floatingPanel.state
+    }
+
+    /// A Boolean value indicating whether a panel controller is attracting the surface to a state anchor.
+    @objc
+    public var isAttracting: Bool {
+        return floatingPanel.isAttracting
+    }
+
+    /// The layout object managed by the controller
+    @objc
+    public var layout: FloatingPanelLayout {
+        get { _layout }
+        set {
+            _layout = newValue
+            if let parent = parent, let layout = newValue as? UIViewController, layout == parent {
+                log.warning("A memory leak will occur by a retain cycle because \(self) owns the parent view controller(\(parent)) as the layout object. Don't let the parent adopt FloatingPanelLayout.")
+            }
+        }
+    }
+
+    /// The behavior object managed by the controller
+    @objc
+    public var behavior: FloatingPanelBehavior {
+        get { _behavior }
+        set {
+            _behavior = newValue
+            if let parent = parent, let behavior = newValue as? UIViewController, behavior == parent {
+                log.warning("A memory leak will occur by a retain cycle because \(self) owns the parent view controller(\(parent)) as the behavior object. Don't let the parent adopt FloatingPanelBehavior.")
+            }
+        }
+    }
+
+    /// The content insets of the tracking scroll view derived from this safe area
+    @objc
+    public var adjustedContentInsets: UIEdgeInsets {
+        return floatingPanel.layoutAdapter.adjustedContentInsets
+    }
+
+    /// The behavior for determining the adjusted content offsets.
+    ///
+    /// This property specifies how the content area of the tracking scroll view is modified using `adjustedContentInsets`. The default value of this property is FloatingPanelController.ContentInsetAdjustmentBehavior.always.
+    @objc 
+    public var contentInsetAdjustmentBehavior: ContentInsetAdjustmentBehavior = .always
+
+    /// A Boolean value that determines whether the removal interaction is enabled.
+    @objc
+    public var isRemovalInteractionEnabled: Bool {
+        @objc(setRemovalInteractionEnabled:) set { floatingPanel.isRemovalInteractionEnabled = newValue }
+        @objc(isRemovalInteractionEnabled) get { return floatingPanel.isRemovalInteractionEnabled }
+    }
+
+    /// The view controller responsible for the content portion of a panel.
+    @objc
+    public var contentViewController: UIViewController? {
+        set { set(contentViewController: newValue) }
+        get { return _contentViewController }
+    }
+
+    /// The NearbyState determines that finger's nearby state.
+    public var nearbyState: FloatingPanelState {
+        let currentY = surfaceLocation.y
+        return floatingPanel.targetPosition(from: currentY, with: .zero)
+    }
+
+    /// Constants that define how a panel content fills in the surface.
+    @objc
+    public var contentMode: ContentMode = .static {
+        didSet {
+            guard state != .hidden else { return }
+            activateLayout(forceLayout: false)
+        }
+    }
+
+    private var _contentViewController: UIViewController?
+
+    private(set) var floatingPanel: Core!
+    private var preSafeAreaInsets: UIEdgeInsets = .zero // Capture the latest one
+    private var safeAreaInsetsObservation: NSKeyValueObservation?
+    private let modalTransition = ModalTransition()
+
+    required public init?(coder aDecoder: NSCoder) {
+        super.init(coder: aDecoder)
+        setUp()
+    }
+
+    override init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?) {
+        super.init(nibName: nil, bundle: nil)
+        setUp()
+    }
+
+    /// Initialize a newly created panel controller.
+    @objc
+    public init(delegate: FloatingPanelControllerDelegate? = nil) {
+        super.init(nibName: nil, bundle: nil)
+        self.delegate = delegate
+        setUp()
+    }
+
+    private func setUp() {
+        _ = FloatingPanelController.dismissSwizzling
+
+        modalPresentationStyle = .custom
+        transitioningDelegate = modalTransition
+
+        let initialLayout: FloatingPanelLayout
+        if let layout = delegate?.floatingPanel?(self, layoutFor: traitCollection) {
+            initialLayout = layout
+        } else {
+            initialLayout = FloatingPanelBottomLayout()
+        }
+        let initialBehavior = FloatingPanelDefaultBehavior()
+
+        floatingPanel = Core(self, layout: initialLayout, behavior: initialBehavior)
+    }
+
+    private func didUpdateDelegate(){
+        if let layout = delegate?.floatingPanel?(self, layoutFor: traitCollection) {
+            _layout = layout
+        }
+    }
+
+    // MARK:- Overrides
+
+    /// Creates the view that the controller manages.
+    open override func loadView() {
+        assert(self.storyboard == nil, "Storyboard isn't supported")
+
+        let view = PassthroughView()
+        view.backgroundColor = .clear
+
+        backdropView.frame = view.bounds
+        view.addSubview(backdropView)
+
+        surfaceView.frame = view.bounds
+        view.addSubview(surfaceView)
+
+        self.view = view as UIView
+    }
+
+    open override func viewDidLayoutSubviews() {
+        super.viewDidLayoutSubviews()
+        if #available(iOS 11.0, *) {
+            // Ensure to update the static constraint of a panel after rotating a device in static mode
+            if contentMode == .static {
+                floatingPanel.layoutAdapter.updateStaticConstraint()
+            }
+        } else {
+            // Because {top,bottom}LayoutGuide is managed as a view
+            if floatingPanel.isAttracting == false {
+                self.update(safeAreaInsets: fp_safeAreaInsets)
+            }
+        }
+    }
+
+    open override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
+        super.viewWillTransition(to: size, with: coordinator)
+
+        if self.view.bounds.size == size {
+            return
+        }
+
+        // Change a layout for the new view size
+        if let newLayout = self.delegate?.floatingPanel?(self, layoutFor: size) {
+            layout = newLayout
+            activateLayout(forceLayout: false)
+        }
+
+        if view.translatesAutoresizingMaskIntoConstraints {
+            view.frame.size = size
+            view.layoutIfNeeded()
+        }
+    }
+
+    open override func willTransition(to newCollection: UITraitCollection, with coordinator: UIViewControllerTransitionCoordinator) {
+        super.willTransition(to: newCollection, with: coordinator)
+
+        if shouldUpdateLayout(from: traitCollection, to: newCollection) == false {
+            return
+        }
+
+        // Change a layout for the new trait collection
+        if let newLayout = self.delegate?.floatingPanel?(self, layoutFor: newCollection) {
+            self.layout = newLayout
+            activateLayout(forceLayout: false)
+        }
+    }
+
+    open override func viewWillDisappear(_ animated: Bool) {
+        super.viewWillDisappear(animated)
+        safeAreaInsetsObservation = nil
+    }
+
+    // MARK:- Child view controller to consult
+    open override var childForStatusBarStyle: UIViewController? {
+        return contentViewController
+    }
+
+    open override var childForStatusBarHidden: UIViewController? {
+        return contentViewController
+    }
+
+    open override var childForScreenEdgesDeferringSystemGestures: UIViewController? {
+        return contentViewController
+    }
+
+    open override var childForHomeIndicatorAutoHidden: UIViewController? {
+        return contentViewController
+    }
+
+    // MARK:- Privates
+
+    private func shouldUpdateLayout(from previous: UITraitCollection, to new: UITraitCollection) -> Bool {
+        return previous.horizontalSizeClass != new.horizontalSizeClass
+            || previous.verticalSizeClass != new.verticalSizeClass
+            || previous.preferredContentSizeCategory != new.preferredContentSizeCategory
+            || previous.layoutDirection != new.layoutDirection
+    }
+
+    private func update(safeAreaInsets: UIEdgeInsets) {
+        guard
+            preSafeAreaInsets != safeAreaInsets
+            else { return }
+
+        log.debug("Update safeAreaInsets", safeAreaInsets)
+
+        // Prevent an infinite loop on iOS 10: setUpLayout() -> viewDidLayoutSubviews() -> setUpLayout()
+        preSafeAreaInsets = safeAreaInsets
+
+        // preserve the current content offset if contentInsetAdjustmentBehavior is `.always`
+        var contentOffset: CGPoint?
+        if contentInsetAdjustmentBehavior == .always {
+            contentOffset = trackingScrollView?.contentOffset
+        }
+
+        floatingPanel.layoutAdapter.updateStaticConstraint()
+
+        if let contentOffset = contentOffset {
+            trackingScrollView?.contentOffset = contentOffset
+        }
+
+        switch contentInsetAdjustmentBehavior {
+        case .always:
+            trackingScrollView?.contentInset = adjustedContentInsets
+        default:
+            break
+        }
+    }
+
+    private func activateLayout(forceLayout: Bool = false) {
+        floatingPanel.layoutAdapter.prepareLayout()
+
+        // preserve the current content offset if contentInsetAdjustmentBehavior is `.always`
+        var contentOffset: CGPoint?
+        if contentInsetAdjustmentBehavior == .always {
+            contentOffset = trackingScrollView?.contentOffset
+        }
+
+        floatingPanel.layoutAdapter.updateStaticConstraint()
+        floatingPanel.layoutAdapter.activateLayout(for: floatingPanel.state, forceLayout: forceLayout)
+
+        if let contentOffset = contentOffset {
+            trackingScrollView?.contentOffset = contentOffset
+        }
+    }
+
+    func remove() {
+        if presentingViewController != nil, parent == nil {
+            delegate?.floatingPanelWillRemove?(self)
+            dismiss(animated: true) { [weak self] in
+                guard let self = self else { return }
+                self.delegate?.floatingPanelDidRemove?(self)
+            }
+        } else {
+            removePanelFromParent(animated: true)
+        }
+    }
+
+    // MARK: - Container view controller interface
+
+    /// Shows the surface view at the initial position defined by the current layout
+    @objc(show:completion:)
+    public func show(animated: Bool = false, completion: (() -> Void)? = nil) {
+        // Must apply the current layout here
+        activateLayout(forceLayout: true)
+
+        if #available(iOS 11.0, *) {
+            // Must track the safeAreaInsets of `self.view` to update the layout.
+            // There are 2 reasons.
+            // 1. This or the parent VC doesn't call viewSafeAreaInsetsDidChange() on the bottom
+            // inset's update expectedly.
+            // 2. The safe area top inset can be variable on the large title navigation bar(iOS11+).
+            // That's why it needs the observation to keep `adjustedContentInsets` correct.
+            safeAreaInsetsObservation = self.view.observe(\.safeAreaInsets, options: [.initial, .new, .old]) { [weak self] (_, change) in
+                // Use `self.view.safeAreaInsets` because `change.newValue` can be nil in particular case when
+                // is reported in https://github.com/SCENEE/FloatingPanel/issues/330
+                guard let self = self, change.oldValue != self.view.safeAreaInsets else { return }
+                self.update(safeAreaInsets: self.view.safeAreaInsets)
+            }
+        } else {
+            // KVOs for topLayoutGuide & bottomLayoutGuide are not effective.
+            // Instead, update(safeAreaInsets:) is called at `viewDidLayoutSubviews()`
+        }
+
+        move(to: floatingPanel.layoutAdapter.initialState,
+             animated: animated,
+             completion: completion)
+    }
+
+    /// Hides the surface view to the hidden position
+    @objc(hide:completion:)
+    public func hide(animated: Bool = false, completion: (() -> Void)? = nil) {
+        move(to: .hidden,
+             animated: animated,
+             completion: completion)
+    }
+
+    /// Adds the view managed by the controller as a child of the specified view controller.
+    /// - Parameters:
+    ///     - parent: A parent view controller object that displays FloatingPanelController's view. A container view controller object isn't applicable.
+    ///     - viewIndex: Insert the surface view managed by the controller below the specified view index. By default, the surface view will be added to the end of the parent list of subviews.
+    ///     - animated: Pass true to animate the presentation; otherwise, pass false.
+    @objc(addPanelToParent:at:animated:)
+    public func addPanel(toParent parent: UIViewController, at viewIndex: Int = -1, animated: Bool = false) {
+        guard self.parent == nil else {
+            log.warning("Already added to a parent(\(parent))")
+            return
+        }
+        assert((parent is UINavigationController) == false, "UINavigationController displays only one child view controller at a time.")
+        assert((parent is UITabBarController) == false, "UITabBarController displays child view controllers with a radio-style selection interface")
+        assert((parent is UISplitViewController) == false, "UISplitViewController manages two child view controllers in a master-detail interface")
+        assert((parent is UITableViewController) == false, "UITableViewController should not be the parent because the view is a table view so that a panel doesn't work well")
+        assert((parent is UICollectionViewController) == false, "UICollectionViewController should not be the parent because the view is a collection view so that a panel doesn't work well")
+
+        if viewIndex < 0 {
+            parent.view.addSubview(self.view)
+        } else {
+            parent.view.insertSubview(self.view, at: viewIndex)
+        }
+
+        parent.addChild(self)
+
+        view.frame = parent.view.bounds // Needed for a correct safe area configuration
+        view.translatesAutoresizingMaskIntoConstraints = false
+        NSLayoutConstraint.activate([
+            self.view.topAnchor.constraint(equalTo: parent.view.topAnchor, constant: 0.0),
+            self.view.leftAnchor.constraint(equalTo: parent.view.leftAnchor, constant: 0.0),
+            self.view.rightAnchor.constraint(equalTo: parent.view.rightAnchor, constant: 0.0),
+            self.view.bottomAnchor.constraint(equalTo: parent.view.bottomAnchor, constant: 0.0),
+            ])
+
+        show(animated: animated) { [weak self] in
+            guard let self = self else { return }
+            self.didMove(toParent: parent)
+        }
+    }
+
+    /// Removes the controller and the managed view from its parent view controller
+    /// - Parameters:
+    ///     - animated: Pass true to animate the presentation; otherwise, pass false.
+    ///     - completion: The block to execute after the view controller is dismissed. This block has no return value and takes no parameters. You may specify nil for this parameter.
+    @objc(removePanelFromParent:completion:)
+    public func removePanelFromParent(animated: Bool, completion: (() -> Void)? = nil) {
+        guard self.parent != nil else {
+            completion?()
+            return
+        }
+
+        delegate?.floatingPanelWillRemove?(self)
+
+        hide(animated: animated) { [weak self] in
+            guard let self = self else { return }
+
+            self.willMove(toParent: nil)
+
+            self.view.removeFromSuperview()
+
+            self.removeFromParent()
+
+            self.delegate?.floatingPanelDidRemove?(self)
+            completion?()
+        }
+    }
+
+    /// Moves the position to the specified position.
+    /// - Parameters:
+    ///     - to: Pass a FloatingPanelPosition value to move the surface view to the position.
+    ///     - animated: Pass true to animate the presentation; otherwise, pass false.
+    ///     - completion: The block to execute after the view controller has finished moving. This block has no return value and takes no parameters. You may specify nil for this parameter.
+    @objc(moveToState:animated:completion:)
+    public func move(to: FloatingPanelState, animated: Bool, completion: (() -> Void)? = nil) {
+        floatingPanel.move(to: to, animated: animated, completion: completion)
+    }
+
+    /// Sets the view controller responsible for the content portion of a panel.
+    public func set(contentViewController: UIViewController?) {
+        if let vc = _contentViewController {
+            vc.willMove(toParent: nil)
+            vc.view.removeFromSuperview()
+            vc.removeFromParent()
+        }
+
+        if let vc = contentViewController {
+            addChild(vc)
+
+            let surfaceView = floatingPanel.surfaceView
+            surfaceView.set(contentView: vc.view)
+
+            vc.didMove(toParent: self)
+        }
+
+        _contentViewController = contentViewController
+    }
+
+    // MARK: - Scroll view tracking
+
+    /// Tracks the specified scroll view to correspond with the scroll.
+    ///
+    /// - Parameters:
+    ///     - scrollView: Specify a scroll view to continuously and seamlessly work in concert with interactions of the surface view
+    @objc(trackScrollView:)
+    public func track(scrollView: UIScrollView) {
+        if let scrollView = floatingPanel.scrollView {
+            untrack(scrollView: scrollView)
+        }
+
+        floatingPanel.scrollView = scrollView
+
+        switch contentInsetAdjustmentBehavior {
+        case .always:
+            if #available(iOS 11.0, *) {
+                scrollView.contentInsetAdjustmentBehavior = .never
+            } else {
+                children.forEach { (vc) in
+                    vc.automaticallyAdjustsScrollViewInsets = false
+                }
+            }
+        default:
+            break
+        }
+    }
+
+    /// Cancel tracking the specify scroll view.
+    ///
+    @objc(untrackScrollView:)
+    public func untrack(scrollView: UIScrollView) {
+        if floatingPanel.scrollView == scrollView {
+            floatingPanel.scrollView = nil
+        }
+    }
+
+    // MARK: - Accessibility
+
+    open override func accessibilityPerformEscape() -> Bool {
+        guard isRemovalInteractionEnabled else { return false }
+        dismiss(animated: true, completion: nil)
+        return true
+    }
+
+    // MARK: - Utilities
+
+    /// Updates the layout object from the delegate and lays out the views managed
+    /// by the controller immediately.
+    ///
+    /// This method updates the `FloatingPanelLayout` object from the delegate and
+    /// then it calls `layoutIfNeeded()` of the root view to force the view
+    /// to update the layout immediately. It can be called in an
+    /// animation block.
+    @objc
+    public func invalidateLayout() {
+        activateLayout(forceLayout: true)
+    }
+
+    /// Returns the surface's position in a panel controller's view for the specified state.
+    ///
+    /// If a panel is top positioned, this returns a point of the bottom-left corner of the surface. If it is left positioned
+    /// this returns a point of top-right corner of the surface. If it is bottom or right positioned, this returns a point
+    /// of the top-left corner of the surface.
+    @objc
+    public func surfaceLocation(for state: FloatingPanelState) -> CGPoint {
+        return floatingPanel.layoutAdapter.surfaceLocation(for: state)
+    }
+
+    /// The surface's position in a panel controller's view.
+    ///
+    /// If a panel is top positioned, this returns a point of the bottom-left corner of the surface. If it is left positioned
+    /// this returns a point of top-right corner of the surface. If it is bottom or right positioned, this returns a point
+    /// of the top-left corner of the surface.
+    @objc
+    public var surfaceLocation: CGPoint {
+        get { floatingPanel.layoutAdapter.surfaceLocation }
+        set { floatingPanel.layoutAdapter.surfaceLocation = newValue }
+    }
+}
+
+extension FloatingPanelController {
+    func notifyDidMove() {
+        #if !TEST
+        guard self.view.window != nil else { return }
+        #endif
+        delegate?.floatingPanelDidMove?(self)
+    }
+
+    func animatorForPresenting(to: FloatingPanelState) -> UIViewPropertyAnimator {
+        if let animator = delegate?.floatingPanel?(self, animatorForPresentingTo: to) {
+            return animator
+        }
+        let timingParameters = UISpringTimingParameters(decelerationRate: UIScrollView.DecelerationRate.fast.rawValue,
+                                                       frequencyResponse: 0.25)
+        return UIViewPropertyAnimator(duration: 0.0,
+                                      timingParameters: timingParameters)
+    }
+
+    func animatorForDismissing(with velocity: CGVector) -> UIViewPropertyAnimator {
+        if let animator = delegate?.floatingPanel?(self, animatorForDismissingWith: velocity) {
+            return animator
+        }
+        let timingParameters = UISpringTimingParameters(decelerationRate: UIScrollView.DecelerationRate.fast.rawValue,
+                                                       frequencyResponse: 0.25,
+                                                       initialVelocity: velocity)
+        return UIViewPropertyAnimator(duration: 0.0,
+                                      timingParameters: timingParameters)
+    }
+}
+
+extension FloatingPanelController {
+    private static let dismissSwizzling: Void = {
+        let aClass: AnyClass! = UIViewController.self //object_getClass(vc)
+        if let imp = class_getMethodImplementation(aClass, #selector(dismiss(animated:completion:))),
+            let originalAltMethod = class_getInstanceMethod(aClass, #selector(fp_original_dismiss(animated:completion:))) {
+            method_setImplementation(originalAltMethod, imp)
+        }
+        let originalMethod = class_getInstanceMethod(aClass, #selector(dismiss(animated:completion:)))
+        let swizzledMethod = class_getInstanceMethod(aClass, #selector(fp_dismiss(animated:completion:)))
+        if let originalMethod = originalMethod, let swizzledMethod = swizzledMethod {
+            method_exchangeImplementations(originalMethod, swizzledMethod)
+        }
+    }()
+}
+
+public extension UIViewController {
+    @objc func fp_original_dismiss(animated flag: Bool, completion: (() -> Void)? = nil) {
+        // Implementation will be replaced by IMP of self.dismiss(animated:completion:)
+    }
+    @objc func fp_dismiss(animated flag: Bool, completion: (() -> Void)? = nil) {
+        // Call dismiss(animated:completion:) to a content view controller
+        if let fpc = parent as? FloatingPanelController {
+            if fpc.presentingViewController != nil {
+                self.fp_original_dismiss(animated: flag, completion: completion)
+            } else {
+                fpc.removePanelFromParent(animated: flag, completion: completion)
+            }
+            return
+        }
+        // Call dismiss(animated:completion:) to FloatingPanelController directly
+        if let fpc = self as? FloatingPanelController {
+            // When a panel is presented modally and it's not a child view controller of the presented view controller.
+            if fpc.presentingViewController != nil, fpc.parent == nil {
+                self.fp_original_dismiss(animated: flag, completion: completion)
+            } else {
+                fpc.removePanelFromParent(animated: flag, completion: completion)
+            }
+            return
+        }
+
+        // For other view controllers
+        self.fp_original_dismiss(animated: flag, completion: completion)
+    }
+}

Sources/FloatingPanel.h

@@ -0,0 +1,11 @@
+// Copyright 2018 the FloatingPanel authors. All rights reserved. MIT license.
+
+#ifndef FloatingPanel_h
+#define FloatingPanel_h
+
+#import <UIKit/UIKit.h>
+
+FOUNDATION_EXPORT double FloatingPanelVersionNumber;
+FOUNDATION_EXPORT const unsigned char FloatingPanelVersionString[];
+
+#endif /* FloatingPanel_h */

Sources/GrabberView.swift

@@ -0,0 +1,33 @@
+// Copyright 2018-Present Shin Yamamoto. All rights reserved. MIT license.
+
+import UIKit
+
+/// A view that presents a grabber handle in the surface of a panel.
+@objc(FloatingPanelGrabberView)
+public class GrabberView: UIView {
+
+    public var barColor = UIColor(displayP3Red: 0.76, green: 0.77, blue: 0.76, alpha: 1.0) { didSet { backgroundColor = barColor } }
+
+    required public init?(coder aDecoder: NSCoder) {
+        super.init(coder: aDecoder)
+    }
+
+    init() {
+        super.init(frame: .zero)
+        backgroundColor = barColor
+    }
+
+    public override func layoutSubviews() {
+        super.layoutSubviews()
+        render()
+    }
+
+    public override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
+        let view = super.hitTest(point, with: event)
+        return view == self ? nil : view
+    }
+
+    private func render() {
+        self.layer.masksToBounds = true
+    }
+}

Sources/Info.plist

@@ -15,7 +15,7 @@
 	<key>CFBundlePackageType</key>
 	<string>FMWK</string>
 	<key>CFBundleShortVersionString</key>
-	<string>1.1.0</string>
+	<string>2.3.0</string>
 	<key>CFBundleVersion</key>
 	<string>$(CURRENT_PROJECT_VERSION)</string>
 </dict>

Sources/Layout.swift

@@ -0,0 +1,842 @@
+// Copyright 2018-Present Shin Yamamoto. All rights reserved. MIT license.
+
+import UIKit
+
+/// An interface for generating layout information for a panel.
+@objc public protocol FloatingPanelLayout {
+    /// Returns the position of a panel in a `FloatingPanelController` view .
+    @objc var position: FloatingPanelPosition { get }
+
+    /// Returns the initial state when a panel is presented.
+    @objc var initialState: FloatingPanelState { get }
+
+    /// Returns the layout anchors to specify the snapping locations for each state.
+    @objc var anchors: [FloatingPanelState: FloatingPanelLayoutAnchoring] { get }
+
+    /// Returns layout constraints to determine the cross dimension of a panel.
+    @objc optional func prepareLayout(surfaceView: UIView, in view: UIView) -> [NSLayoutConstraint]
+
+    /// Returns the alpha value of the backdrop of a panel for each state.
+    @objc optional func backdropAlpha(for state: FloatingPanelState) -> CGFloat
+}
+
+/// A layout object that lays out a panel in bottom sheet style.
+@objcMembers
+open class FloatingPanelBottomLayout: NSObject, FloatingPanelLayout {
+    public override init() {
+        super.init()
+    }
+    open var initialState: FloatingPanelState {
+        return .half
+    }
+
+    open var anchors: [FloatingPanelState: FloatingPanelLayoutAnchoring]  {
+        return [
+            .full: FloatingPanelLayoutAnchor(absoluteInset: 18.0, edge: .top, referenceGuide: .safeArea),
+            .half: FloatingPanelLayoutAnchor(fractionalInset: 0.5, edge: .bottom, referenceGuide: .safeArea),
+            .tip: FloatingPanelLayoutAnchor(absoluteInset: 69.0, edge: .bottom, referenceGuide: .safeArea),
+        ]
+    }
+
+    open var position: FloatingPanelPosition {
+        return .bottom
+    }
+
+    open func prepareLayout(surfaceView: UIView, in view: UIView) -> [NSLayoutConstraint] {
+        return [
+            surfaceView.leftAnchor.constraint(equalTo: view.fp_safeAreaLayoutGuide.leftAnchor, constant: 0.0),
+            surfaceView.rightAnchor.constraint(equalTo: view.fp_safeAreaLayoutGuide.rightAnchor, constant: 0.0),
+        ]
+    }
+
+    open func backdropAlpha(for state: FloatingPanelState) -> CGFloat {
+        return state == .full ? 0.3 : 0.0
+    }
+}
+
+struct LayoutSegment {
+    let lower: FloatingPanelState?
+    let upper: FloatingPanelState?
+}
+
+class LayoutAdapter {
+    private unowned var vc: FloatingPanelController
+    private let defaultLayout = FloatingPanelBottomLayout()
+
+    fileprivate var layout: FloatingPanelLayout {
+        didSet {
+            surfaceView.position = position
+        }
+    }
+
+    private var surfaceView: SurfaceView {
+        return vc.surfaceView
+    }
+    private var backdropView: BackdropView {
+        return vc.backdropView
+    }
+    private var safeAreaInsets: UIEdgeInsets {
+        return vc.fp_safeAreaInsets
+    }
+
+    private var initialConst: CGFloat = 0.0
+
+    private var fixedConstraints: [NSLayoutConstraint] = []
+
+    private var stateConstraints: [FloatingPanelState: [NSLayoutConstraint]] = [:]
+    private var offConstraints: [NSLayoutConstraint] = []
+    private var fitToBoundsConstraint: NSLayoutConstraint?
+
+    private(set) var interactionConstraint: NSLayoutConstraint?
+    private(set) var attractionConstraint: NSLayoutConstraint?
+
+    private var staticConstraint: NSLayoutConstraint?
+
+    private var activeStates: Set<FloatingPanelState> {
+        return Set(layout.anchors.keys)
+    }
+
+    var initialState: FloatingPanelState {
+        layout.initialState
+    }
+
+    var position: FloatingPanelPosition {
+        layout.position
+    }
+
+    var orderedStates: [FloatingPanelState] {
+        return activeStates.sorted(by: {
+            return $0.order < $1.order
+        })
+    }
+
+    var validStates: Set<FloatingPanelState> {
+        return activeStates.union([.hidden])
+    }
+
+    var sortedDirectionalStates: [FloatingPanelState] {
+        return activeStates.sorted(by: {
+            switch position {
+            case .top, .left:
+                return $0.order < $1.order
+            case .bottom, .right:
+                return $0.order > $1.order
+            }
+        })
+    }
+
+    private var directionalLeastState: FloatingPanelState {
+        return sortedDirectionalStates.first ?? .hidden
+    }
+
+    private var directionalMostState: FloatingPanelState {
+        return sortedDirectionalStates.last ?? .hidden
+    }
+
+    var edgeLeastState: FloatingPanelState {
+        if orderedStates.count == 1 {
+            return .hidden
+        }
+        return orderedStates.first ?? .hidden
+    }
+
+    var edgeMostState: FloatingPanelState {
+        if orderedStates.count == 1 {
+            return orderedStates[0]
+        }
+        return orderedStates.last ?? .hidden
+    }
+
+    var edgeMostY: CGFloat {
+        return position(for: edgeMostState)
+    }
+
+    var adjustedContentInsets: UIEdgeInsets {
+        switch position {
+        case .top:
+            return UIEdgeInsets(top: safeAreaInsets.top,
+                                left: 0.0,
+                                bottom: 0.0,
+                                right: 0.0)
+        case .left:
+            return UIEdgeInsets(top: 0.0,
+                                left: safeAreaInsets.left,
+                                bottom: 0.0,
+                                right: 0.0)
+        case .bottom:
+            return UIEdgeInsets(top: 0.0,
+                                left: 0.0,
+                                bottom: safeAreaInsets.bottom,
+                                right: 0.0)
+        case .right:
+            return UIEdgeInsets(top: 0.0,
+                                left: 0.0,
+                                bottom: 0.0,
+                                right: safeAreaInsets.right)
+        }
+    }
+
+    /*
+    Returns a constraint based value in the interaction and animation.
+
+    So that it doesn't need to call `surfaceView.layoutIfNeeded()`
+    after every interaction and animation update. It has an effect on
+    the smooth interaction because the content view doesn't need to update
+    its layout frequently.
+    */
+    var surfaceLocation: CGPoint {
+        get {
+            var pos: CGFloat
+            if let constraint = interactionConstraint {
+                pos = constraint.constant
+            } else if let animationConstraint = attractionConstraint, let anchor = layout.anchors[vc.state] {
+                switch position {
+                case .top, .bottom:
+                    switch referenceEdge(of: anchor) {
+                    case .top:
+                        pos = animationConstraint.constant
+                        if anchor.referenceGuide == .safeArea {
+                            pos += safeAreaInsets.top
+                        }
+                    case .bottom:
+                        pos = vc.view.bounds.height + animationConstraint.constant
+                        if anchor.referenceGuide == .safeArea {
+                            pos -= safeAreaInsets.bottom
+                        }
+                    default:
+                        fatalError("Unsupported reference edges")
+                    }
+                case .left, .right:
+                    switch referenceEdge(of: anchor) {
+                    case .left:
+                        pos = animationConstraint.constant
+                        if anchor.referenceGuide == .safeArea {
+                            pos += safeAreaInsets.left
+                        }
+                    case .right:
+                        pos = vc.view.bounds.width + animationConstraint.constant
+                        if anchor.referenceGuide == .safeArea {
+                            pos -= safeAreaInsets.right
+                        }
+                    default:
+                        fatalError("Unsupported reference edges")
+                    }
+                }
+            } else {
+                pos = displayTrunc(edgePosition(surfaceView.frame), by: surfaceView.fp_displayScale)
+            }
+            switch position {
+            case .top, .bottom:
+                return CGPoint(x: 0.0, y: pos)
+            case .left, .right:
+                return CGPoint(x: pos, y: 0.0)
+            }
+        }
+        set {
+            let pos = position.mainLocation(newValue)
+            if let constraint = interactionConstraint {
+                constraint.constant = pos
+            } else if let animationConstraint = attractionConstraint, let anchor = layout.anchors[vc.state] {
+                let refEdge = referenceEdge(of: anchor)
+                switch refEdge {
+                case .top, .left:
+                    animationConstraint.constant = pos
+                    if anchor.referenceGuide == .safeArea {
+                        animationConstraint.constant -= refEdge.inset(of: safeAreaInsets)
+                    }
+                case .bottom, .right:
+                    animationConstraint.constant = pos - position.mainDimension(vc.view.bounds.size)
+                    if anchor.referenceGuide == .safeArea {
+                        animationConstraint.constant += refEdge.inset(of: safeAreaInsets)
+                    }
+                }
+            } else {
+                switch position {
+                case .top:
+                    return surfaceView.frame.origin.y = pos - surfaceView.bounds.height
+                case .left:
+                    return surfaceView.frame.origin.x = pos - surfaceView.bounds.width
+                case .bottom:
+                    return surfaceView.frame.origin.y = pos
+                case .right:
+                    return surfaceView.frame.origin.x = pos
+                }
+            }
+        }
+    }
+
+    var offsetFromEdgeMost: CGFloat {
+        switch position {
+        case .top, .left:
+            return edgePosition(surfaceView.presentationFrame) - position(for: directionalMostState)
+        case .bottom, .right:
+            return position(for: directionalLeastState) - edgePosition(surfaceView.presentationFrame)
+        }
+    }
+
+    private var hiddenAnchor: FloatingPanelLayoutAnchoring {
+        switch position {
+        case .top:
+            return FloatingPanelLayoutAnchor(absoluteInset: -100, edge: .top, referenceGuide: .superview)
+        case .left:
+            return FloatingPanelLayoutAnchor(absoluteInset: -100, edge: .left, referenceGuide: .superview)
+        case .bottom:
+            return FloatingPanelLayoutAnchor(absoluteInset: -100, edge: .bottom, referenceGuide: .superview)
+        case .right:
+            return FloatingPanelLayoutAnchor(absoluteInset: -100, edge: .right, referenceGuide: .superview)
+        }
+    }
+
+    init(vc: FloatingPanelController, layout: FloatingPanelLayout) {
+        self.vc = vc
+        self.layout = layout
+    }
+
+    func surfaceLocation(for state: FloatingPanelState) -> CGPoint {
+        let pos = displayTrunc(position(for: state), by: surfaceView.fp_displayScale)
+        switch layout.position {
+        case .top, .bottom:
+            return CGPoint(x: 0.0, y: pos)
+        case .left, .right:
+            return CGPoint(x: pos, y: 0.0)
+        }
+    }
+
+    func position(for state: FloatingPanelState) -> CGFloat {
+        let bounds = vc.view.bounds
+        let anchor = layout.anchors[state] ?? self.hiddenAnchor
+
+        switch anchor {
+        case let anchor as FloatingPanelIntrinsicLayoutAnchor:
+            let intrinsicLength = position.mainDimension(surfaceView.intrinsicContentSize)
+            let diff = anchor.isAbsolute ? anchor.offset : intrinsicLength * anchor.offset
+
+            switch position {
+            case .top, .left:
+                var base: CGFloat = 0.0
+                if anchor.referenceGuide == .safeArea {
+                    base += position.inset(safeAreaInsets)
+                }
+                return base + intrinsicLength - diff
+            case .bottom, .right:
+                var base = position.mainDimension(bounds.size)
+                if anchor.referenceGuide == .safeArea {
+                    base -= position.inset(safeAreaInsets)
+                }
+                return base - intrinsicLength + diff
+            }
+        case let anchor as FloatingPanelAdaptiveLayoutAnchor:
+            let dimension = layout.position.mainDimension(anchor.contentLayoutGuide.layoutFrame.size)
+            let diff = anchor.distance(from: dimension)
+            var referenceBoundsLength = layout.position.mainDimension(bounds.size)
+            switch layout.position {
+            case .top, .left:
+                if anchor.referenceGuide == .safeArea {
+                    referenceBoundsLength += position.inset(safeAreaInsets)
+                }
+                return dimension - diff
+            case .bottom, .right:
+                if anchor.referenceGuide == .safeArea {
+                    referenceBoundsLength -= position.inset(safeAreaInsets)
+                }
+                return referenceBoundsLength - dimension + diff
+            }
+        case let anchor as FloatingPanelLayoutAnchor:
+            let referenceBounds = anchor.referenceGuide == .safeArea ? bounds.inset(by: safeAreaInsets) : bounds
+            let diff = anchor.isAbsolute ? anchor.inset : position.mainDimension(referenceBounds.size) * anchor.inset
+            switch anchor.referenceEdge {
+            case .top:
+                return referenceBounds.minY + diff
+            case .left:
+                return referenceBounds.minX + diff
+            case .bottom:
+                return referenceBounds.maxY - diff
+            case .right:
+                return referenceBounds.maxX - diff
+            }
+        default:
+            fatalError("Unsupported a FloatingPanelLayoutAnchoring object")
+        }
+    }
+
+    func isIntrinsicAnchor(state: FloatingPanelState) -> Bool {
+        return layout.anchors[state] is FloatingPanelIntrinsicLayoutAnchor
+    }
+
+    private func edgePosition(_ frame: CGRect) -> CGFloat {
+        switch position {
+        case .top:
+            return frame.maxY
+        case .left:
+            return frame.maxX
+        case .bottom:
+            return frame.minY
+        case .right:
+            return frame.minX
+        }
+    }
+
+    private func referenceEdge(of anchor: FloatingPanelLayoutAnchoring) -> FloatingPanelReferenceEdge {
+        switch anchor {
+        case is FloatingPanelIntrinsicLayoutAnchor,
+            is FloatingPanelAdaptiveLayoutAnchor:
+            switch position {
+            case .top: return .top
+            case .left: return .left
+            case .bottom: return .bottom
+            case .right: return .right
+            }
+        case let anchor as FloatingPanelLayoutAnchor:
+            return anchor.referenceEdge
+        default:
+            fatalError("Unsupported a FloatingPanelLayoutAnchoring object")
+        }
+    }
+
+    func prepareLayout() {
+        NSLayoutConstraint.deactivate(fixedConstraints)
+
+        surfaceView.translatesAutoresizingMaskIntoConstraints = false
+        backdropView.translatesAutoresizingMaskIntoConstraints = false
+
+        // Fixed constraints of surface and backdrop views
+        let surfaceConstraints: [NSLayoutConstraint]
+        if let constraints = layout.prepareLayout?(surfaceView: surfaceView, in: vc.view) {
+            surfaceConstraints = constraints
+        } else {
+            switch position {
+            case .top, .bottom:
+                surfaceConstraints = [
+                    surfaceView.leftAnchor.constraint(equalTo: vc.fp_safeAreaLayoutGuide.leftAnchor, constant: 0.0),
+                    surfaceView.rightAnchor.constraint(equalTo: vc.fp_safeAreaLayoutGuide.rightAnchor, constant: 0.0),
+                ]
+            case .left, .right:
+                surfaceConstraints = [
+                    surfaceView.topAnchor.constraint(equalTo: vc.fp_safeAreaLayoutGuide.topAnchor, constant: 0.0),
+                    surfaceView.bottomAnchor.constraint(equalTo: vc.fp_safeAreaLayoutGuide.bottomAnchor, constant: 0.0),
+                ]
+            }
+        }
+        let backdropConstraints = [
+            backdropView.topAnchor.constraint(equalTo: vc.view.topAnchor, constant: 0.0),
+            backdropView.leftAnchor.constraint(equalTo: vc.view.leftAnchor,constant: 0.0),
+            backdropView.rightAnchor.constraint(equalTo: vc.view.rightAnchor, constant: 0.0),
+            backdropView.bottomAnchor.constraint(equalTo: vc.view.bottomAnchor, constant: 0.0),
+            ]
+
+        fixedConstraints = surfaceConstraints + backdropConstraints
+
+        NSLayoutConstraint.deactivate(constraint: self.fitToBoundsConstraint)
+        self.fitToBoundsConstraint = nil
+
+        if vc.contentMode == .fitToBounds {
+            switch position {
+            case .top:
+                fitToBoundsConstraint = surfaceView.topAnchor.constraint(equalTo: vc.view.topAnchor, constant: 0.0)
+                fitToBoundsConstraint?.identifier = "FloatingPanel-fit-to-top"
+            case .left:
+                fitToBoundsConstraint = surfaceView.leftAnchor.constraint(equalTo: vc.view.leftAnchor, constant: 0.0)
+                fitToBoundsConstraint?.identifier = "FloatingPanel-fit-to-left"
+            case .bottom:
+                fitToBoundsConstraint = surfaceView.bottomAnchor.constraint(equalTo: vc.view.bottomAnchor, constant: 0.0)
+                fitToBoundsConstraint?.identifier = "FloatingPanel-fit-to-bottom"
+            case .right:
+                fitToBoundsConstraint = surfaceView.rightAnchor.constraint(equalTo: vc.view.rightAnchor, constant: 0.0)
+                fitToBoundsConstraint?.identifier = "FloatingPanel-fit-to-right"
+            }
+            fitToBoundsConstraint?.priority = .defaultHigh
+        }
+
+        updateStateConstraints()
+    }
+
+    private func updateStateConstraints() {
+        let allStateConstraints = stateConstraints.flatMap { $1 }
+        NSLayoutConstraint.deactivate(allStateConstraints + offConstraints)
+        stateConstraints.removeAll()
+        for state in layout.anchors.keys {
+            stateConstraints[state] = layout.anchors[state]?
+                .layoutConstraints(vc, for: position)
+                .map{ $0.identifier = "FloatingPanel-\(state)-constraint"; return $0 }
+        }
+        let hiddenAnchor = layout.anchors[.hidden] ?? self.hiddenAnchor
+        offConstraints = hiddenAnchor.layoutConstraints(vc, for: position)
+        offConstraints.forEach {
+            $0.identifier = "FloatingPanel-hidden-constraint"
+        }
+    }
+
+    func startInteraction(at state: FloatingPanelState, offset: CGPoint = .zero) {
+        if let constraint = interactionConstraint {
+            initialConst = constraint.constant
+            return
+        }
+
+        tearDownAttraction()
+
+        NSLayoutConstraint.deactivate(stateConstraints.flatMap { $1 } + offConstraints)
+
+        initialConst = edgePosition(surfaceView.frame) + offset.y
+
+        let constraint: NSLayoutConstraint
+        switch position {
+        case .top:
+            constraint = surfaceView.bottomAnchor.constraint(equalTo: vc.view.topAnchor, constant: initialConst)
+        case .left:
+            constraint = surfaceView.rightAnchor.constraint(equalTo: vc.view.leftAnchor, constant: initialConst)
+        case .bottom:
+            constraint = surfaceView.topAnchor.constraint(equalTo: vc.view.topAnchor, constant: initialConst)
+        case .right:
+            constraint = surfaceView.leftAnchor.constraint(equalTo: vc.view.leftAnchor, constant: initialConst)
+        }
+
+        constraint.priority = .required
+        constraint.identifier = "FloatingPanel-interaction"
+
+        NSLayoutConstraint.activate([constraint])
+        self.interactionConstraint = constraint
+    }
+
+    func endInteraction(at state: FloatingPanelState) {
+        // Don't deactivate `interactiveTopConstraint` here because it leads to
+        // unsatisfiable constraints
+
+        if self.interactionConstraint == nil {
+            // Activate `interactiveTopConstraint` for `fitToBounds` mode.
+            // It goes through this path when the pan gesture state jumps
+            // from .begin to .end.
+            startInteraction(at: state)
+        }
+    }
+
+    func setUpAttraction(to state: FloatingPanelState) -> (NSLayoutConstraint, CGFloat) {
+        NSLayoutConstraint.deactivate(constraint: attractionConstraint)
+
+        let anchor = layout.anchors[state] ?? self.hiddenAnchor
+
+        NSLayoutConstraint.deactivate(stateConstraints.flatMap { $1 } + offConstraints)
+        NSLayoutConstraint.deactivate(constraint: interactionConstraint)
+        interactionConstraint = nil
+
+        let layoutGuideProvider: LayoutGuideProvider
+        switch anchor.referenceGuide {
+        case .safeArea:
+            layoutGuideProvider = vc.fp_safeAreaLayoutGuide
+        case .superview:
+            layoutGuideProvider = vc.view
+        }
+        let currentY = position.mainLocation(surfaceLocation)
+        let baseHeight = position.mainDimension(vc.view.bounds.size)
+
+        let animationConstraint: NSLayoutConstraint
+        var targetY = position(for: state)
+
+        switch position {
+        case .top:
+            switch referenceEdge(of: anchor) {
+            case .top:
+                animationConstraint = surfaceView.bottomAnchor.constraint(equalTo: layoutGuideProvider.topAnchor,
+                                                                          constant: currentY)
+                if anchor.referenceGuide == .safeArea {
+                    animationConstraint.constant -= safeAreaInsets.top
+                    targetY -= safeAreaInsets.top
+                }
+            case .bottom:
+                let baseHeight = vc.view.bounds.height
+                targetY = -(baseHeight - targetY)
+                animationConstraint = surfaceView.bottomAnchor.constraint(equalTo: layoutGuideProvider.bottomAnchor,
+                                                                          constant: -(baseHeight - currentY))
+                if anchor.referenceGuide == .safeArea {
+                    animationConstraint.constant += safeAreaInsets.bottom
+                    targetY += safeAreaInsets.bottom
+
+                }
+            default:
+                fatalError("Unsupported reference edges")
+            }
+        case .left:
+            switch referenceEdge(of: anchor) {
+            case .left:
+                animationConstraint = surfaceView.rightAnchor.constraint(equalTo: layoutGuideProvider.leftAnchor,
+                                                                          constant: currentY)
+                if anchor.referenceGuide == .safeArea {
+                    animationConstraint.constant -= safeAreaInsets.right
+                    targetY -= safeAreaInsets.right
+                }
+            case .right:
+                targetY = -(baseHeight - targetY)
+                animationConstraint = surfaceView.rightAnchor.constraint(equalTo: layoutGuideProvider.rightAnchor,
+                                                                          constant: -(baseHeight - currentY))
+                if anchor.referenceGuide == .safeArea {
+                    animationConstraint.constant += safeAreaInsets.left
+                    targetY += safeAreaInsets.left
+                }
+            default:
+                fatalError("Unsupported reference edges")
+            }
+        case .bottom:
+            switch referenceEdge(of: anchor) {
+            case .top:
+                animationConstraint = surfaceView.topAnchor.constraint(equalTo: layoutGuideProvider.topAnchor,
+                                                                       constant: currentY)
+                if anchor.referenceGuide == .safeArea {
+                    animationConstraint.constant -= safeAreaInsets.top
+                    targetY -= safeAreaInsets.top
+                }
+            case .bottom:
+                targetY = -(baseHeight - targetY)
+                animationConstraint = surfaceView.topAnchor.constraint(equalTo: layoutGuideProvider.bottomAnchor,
+                                                                       constant: -(baseHeight - currentY))
+                if anchor.referenceGuide == .safeArea {
+                    animationConstraint.constant += safeAreaInsets.bottom
+                    targetY += safeAreaInsets.bottom
+
+                }
+            default:
+                fatalError("Unsupported reference edges")
+            }
+        case .right:
+            switch referenceEdge(of: anchor) {
+            case .left:
+                animationConstraint = surfaceView.leftAnchor.constraint(equalTo: layoutGuideProvider.leftAnchor,
+                                                                         constant: currentY)
+                if anchor.referenceGuide == .safeArea {
+                    animationConstraint.constant -= safeAreaInsets.left
+                    targetY -= safeAreaInsets.left
+                }
+            case .right:
+                targetY = -(baseHeight - targetY)
+                animationConstraint = surfaceView.leftAnchor.constraint(equalTo: layoutGuideProvider.rightAnchor,
+                                                                         constant: -(baseHeight - currentY))
+                if anchor.referenceGuide == .safeArea {
+                    animationConstraint.constant += safeAreaInsets.right
+                    targetY += safeAreaInsets.right
+                }
+            default:
+                fatalError("Unsupported reference edges")
+            }
+        }
+
+        animationConstraint.priority = .defaultHigh
+        animationConstraint.identifier = "FloatingPanel-attraction"
+
+        NSLayoutConstraint.activate([animationConstraint])
+        self.attractionConstraint = animationConstraint
+        return (animationConstraint, targetY)
+    }
+
+    private func tearDownAttraction() {
+        NSLayoutConstraint.deactivate(constraint: attractionConstraint)
+        attractionConstraint = nil
+    }
+
+    // The method is separated from prepareLayout(to:) for the rotation support
+    // It must be called in FloatingPanelController.traitCollectionDidChange(_:)
+    func updateStaticConstraint() {
+        NSLayoutConstraint.deactivate(constraint: staticConstraint)
+        staticConstraint = nil
+
+        if vc.contentMode == .fitToBounds {
+            surfaceView.containerOverflow = 0
+            return
+        }
+
+        let anchor = layout.anchors[self.edgeMostState]!
+        let surfaceAnchor = position.mainDimensionAnchor(surfaceView)
+        switch anchor {
+        case let anchor as FloatingPanelIntrinsicLayoutAnchor:
+            var constant = position.mainDimension(surfaceView.intrinsicContentSize)
+            if anchor.referenceGuide == .safeArea {
+                constant += position.inset(safeAreaInsets)
+            }
+            staticConstraint = surfaceAnchor.constraint(equalToConstant: constant)
+        case let anchor as FloatingPanelAdaptiveLayoutAnchor:
+            let constant: CGFloat
+            if anchor.referenceGuide == .safeArea {
+                constant = position.inset(safeAreaInsets)
+            } else {
+                constant = 0.0
+            }
+            let baseAnchor = position.mainDimensionAnchor(anchor.contentLayoutGuide)
+            staticConstraint = surfaceAnchor.constraint(equalTo: baseAnchor, constant: constant)
+        default:
+            switch position {
+            case .top, .left:
+                staticConstraint = surfaceAnchor.constraint(equalToConstant: position(for: self.directionalMostState))
+            case .bottom, .right:
+                let rootViewAnchor = position.mainDimensionAnchor(vc.view)
+                staticConstraint = rootViewAnchor.constraint(equalTo: surfaceAnchor,
+                                                             constant: position(for: self.directionalLeastState))
+            }
+        }
+
+        switch position {
+        case .top, .bottom:
+            staticConstraint?.identifier = "FloatingPanel-static-height"
+        case .left, .right:
+            staticConstraint?.identifier = "FloatingPanel-static-width"
+        }
+
+        NSLayoutConstraint.activate(constraint: staticConstraint)
+
+        surfaceView.containerOverflow = position.mainDimension(vc.view.bounds.size)
+    }
+
+    func updateInteractiveEdgeConstraint(diff: CGFloat, overflow: Bool, allowsRubberBanding: (UIRectEdge) -> Bool) {
+        defer {
+            log.debug("update surface location = \(surfaceLocation)")
+        }
+
+        let minConst: CGFloat = position(for: directionalLeastState)
+        let maxConst: CGFloat = position(for: directionalMostState)
+
+        var const = initialConst + diff
+
+        let base = position.mainDimension(vc.view.bounds.size)
+        // Rubber-banding top buffer
+        if allowsRubberBanding(.top), const < minConst {
+            let buffer = minConst - const
+            const = minConst - rubberBandEffect(for: buffer, base: base)
+        }
+
+        // Rubber-banding bottom buffer
+        if allowsRubberBanding(.bottom), const > maxConst {
+            let buffer = const - maxConst
+            const = maxConst + rubberBandEffect(for: buffer, base: base)
+        }
+
+        if overflow == false {
+            const = min(max(const, minConst), maxConst)
+        }
+
+        interactionConstraint?.constant = const
+    }
+
+    // According to @chpwn's tweet: https://twitter.com/chpwn/status/285540192096497664
+    // x = distance from the edge
+    // c = constant value, UIScrollView uses 0.55
+    // d = dimension, either width or height
+    private func rubberBandEffect(for buffer: CGFloat, base: CGFloat) -> CGFloat {
+        return (1.0 - (1.0 / ((buffer * 0.55 / base) + 1.0))) * base
+    }
+
+    func activateLayout(for state: FloatingPanelState, forceLayout: Bool = false) {
+        defer {
+            if forceLayout {
+                layoutSurfaceIfNeeded()
+                log.debug("activateLayout for \(state) -- surface.presentation = \(self.surfaceView.presentationFrame) surface.frame = \(self.surfaceView.frame)")
+            } else {
+                log.debug("activateLayout for \(state)")
+            }
+        }
+
+        // Must deactivate `interactiveTopConstraint` here
+        NSLayoutConstraint.deactivate(constraint: self.interactionConstraint)
+        self.interactionConstraint = nil
+
+        tearDownAttraction()
+
+        NSLayoutConstraint.activate(fixedConstraints)
+
+        if vc.contentMode == .fitToBounds {
+            NSLayoutConstraint.activate(constraint: self.fitToBoundsConstraint)
+        }
+
+        var state = state
+
+        setBackdropAlpha(of: state)
+
+        if validStates.contains(state) == false {
+            state = layout.initialState
+        }
+
+        // Recalculate the intrinsic size of a content view. This is because
+        // UIView.systemLayoutSizeFitting() returns a different size between an
+        // on-screen and off-screen view which includes
+        // UIStackView(i.e. Settings view in Samples.app)
+        updateStateConstraints()
+
+        switch state {
+        case .hidden:
+            NSLayoutConstraint.activate(offConstraints)
+        default:
+            if let constraints = stateConstraints[state] {
+                NSLayoutConstraint.activate(constraints)
+            } else {
+                log.error("Couldn't find any constraints for \(state)")
+            }
+        }
+    }
+
+    private func layoutSurfaceIfNeeded() {
+        #if !TEST
+        guard surfaceView.window != nil else { return }
+        #endif
+        surfaceView.superview?.layoutIfNeeded()
+    }
+
+    private func setBackdropAlpha(of target: FloatingPanelState) {
+        if target == .hidden {
+            self.backdropView.alpha = 0.0
+        } else {
+            self.backdropView.alpha = backdropAlpha(for: target)
+        }
+    }
+
+    func backdropAlpha(for state: FloatingPanelState) -> CGFloat {
+        return layout.backdropAlpha?(for: state) ?? defaultLayout.backdropAlpha(for: state)
+    }
+
+    fileprivate func checkLayout() {
+        // Verify layout configurations
+        assert(activeStates.count > 0)
+        assert(validStates.contains(layout.initialState),
+               "Does not include an initial state (\(layout.initialState)) in (\(validStates))")
+        /* This assertion does not work in a device rotating
+         let statePosOrder = activeStates.sorted(by: { position(for: $0) < position(for: $1) })
+         assert(sortedDirectionalStates == statePosOrder,
+               "Check your layout anchors because the state order(\(statePosOrder)) must be (\(sortedDirectionalStates))).")
+         */
+    }
+}
+
+extension LayoutAdapter {
+    func segment(at pos: CGFloat, forward: Bool) -> LayoutSegment {
+        /// ----------------------->Y
+        /// --> forward                <-- backward
+        /// |-------|===o===|-------|  |-------|-------|===o===|
+        /// |-------|-------x=======|  |-------|=======x-------|
+        /// |-------|-------|===o===|  |-------|===o===|-------|
+        /// pos: o/x, segment: =
+
+        let sortedStates = sortedDirectionalStates
+
+        let upperIndex: Int?
+        if forward {
+            upperIndex = sortedStates.firstIndex(where: { pos < position(for: $0) })
+        } else {
+            upperIndex = sortedStates.firstIndex(where: { pos <= position(for: $0) })
+        }
+
+        switch upperIndex {
+        case 0:
+            return LayoutSegment(lower: nil, upper: sortedStates.first)
+        case let upperIndex?:
+            return LayoutSegment(lower: sortedStates[upperIndex - 1], upper: sortedStates[upperIndex])
+        default:
+            return LayoutSegment(lower: sortedStates[sortedStates.endIndex - 1], upper: nil)
+        }
+    }
+}
+
+extension FloatingPanelController {
+    var _layout: FloatingPanelLayout {
+        get {
+            floatingPanel.layoutAdapter.layout
+        }
+        set {
+            floatingPanel.layoutAdapter.layout = newValue
+            floatingPanel.layoutAdapter.checkLayout()
+        }
+    }
+}

Sources/LayoutAnchoring.swift

@@ -0,0 +1,201 @@
+// Copyright 2018-Present Shin Yamamoto. All rights reserved. MIT license.
+
+import UIKit
+
+/// An interface for implementing custom layout anchor objects.
+@objc public protocol FloatingPanelLayoutAnchoring {
+    var referenceGuide: FloatingPanelLayoutReferenceGuide { get }
+    func layoutConstraints(_ fpc: FloatingPanelController, for position: FloatingPanelPosition) -> [NSLayoutConstraint]
+}
+
+/// An object that defines how to settles a panel with insets from an edge of a reference rectangle.
+@objc final public class FloatingPanelLayoutAnchor: NSObject, FloatingPanelLayoutAnchoring /*, NSCopying */ {
+
+    /// Returns a layout anchor with the specified inset by an absolute value, edge and reference guide for a panel.
+    ///
+    /// The inset is an amount to inset a panel from an edge of the reference guide.  The edge refers to a panel
+    /// positioning.
+    @objc public init(absoluteInset: CGFloat, edge: FloatingPanelReferenceEdge, referenceGuide: FloatingPanelLayoutReferenceGuide) {
+        self.inset = absoluteInset
+        self.referenceGuide = referenceGuide
+        self.referenceEdge = edge
+        self.isAbsolute = true
+    }
+
+    /// Returns a layout anchor with the specified inset by a fractional value, edge and reference guide for a panel.
+    ///
+    /// The inset is an amount to inset a panel from the edge of the specified reference guide. The value is
+    /// a floating-point number in the range 0.0 to 1.0, where 0.0 represents zero distance from the edge and
+    /// 1.0 represents a distance to the opposite edge.
+    @objc public init(fractionalInset: CGFloat, edge: FloatingPanelReferenceEdge, referenceGuide: FloatingPanelLayoutReferenceGuide) {
+        self.inset = fractionalInset
+        self.referenceGuide = referenceGuide
+        self.referenceEdge = edge
+        self.isAbsolute = false
+    }
+    let inset: CGFloat
+    let isAbsolute: Bool
+    /// The reference rectangle area for the inset.
+    @objc public let referenceGuide: FloatingPanelLayoutReferenceGuide
+    @objc let referenceEdge: FloatingPanelReferenceEdge
+}
+
+public extension FloatingPanelLayoutAnchor {
+    func layoutConstraints(_ vc: FloatingPanelController, for position: FloatingPanelPosition) -> [NSLayoutConstraint] {
+        let layoutGuide = referenceGuide.layoutGuide(vc: vc)
+        switch position {
+        case .top:
+            return layoutConstraints(layoutGuide, for: vc.surfaceView.bottomAnchor)
+        case .left:
+            return layoutConstraints(layoutGuide, for: vc.surfaceView.rightAnchor)
+        case .bottom:
+            return layoutConstraints(layoutGuide, for:  vc.surfaceView.topAnchor)
+        case .right:
+            return layoutConstraints(layoutGuide, for: vc.surfaceView.leftAnchor)
+        }
+    }
+
+    private func layoutConstraints(_ layoutGuide: LayoutGuideProvider, for edgeAnchor: NSLayoutYAxisAnchor) -> [NSLayoutConstraint] {
+        switch referenceEdge {
+        case .top:
+            if isAbsolute {
+                return [edgeAnchor.constraint(equalTo: layoutGuide.topAnchor, constant: inset)]
+            }
+            let offsetAnchor = layoutGuide.topAnchor.anchorWithOffset(to: edgeAnchor)
+            return [offsetAnchor.constraint(equalTo:layoutGuide.heightAnchor, multiplier: inset)]
+        case .bottom:
+            if isAbsolute {
+                return [layoutGuide.bottomAnchor.constraint(equalTo: edgeAnchor, constant: inset)]
+            }
+            let offsetAnchor = edgeAnchor.anchorWithOffset(to: layoutGuide.bottomAnchor)
+            return [offsetAnchor.constraint(equalTo: layoutGuide.heightAnchor, multiplier: inset)]
+        default:
+            fatalError("Unsupported reference edges")
+        }
+    }
+
+    private func layoutConstraints(_ layoutGuide: LayoutGuideProvider, for edgeAnchor: NSLayoutXAxisAnchor) -> [NSLayoutConstraint] {
+        switch referenceEdge {
+        case .left:
+            if isAbsolute {
+                return [edgeAnchor.constraint(equalTo: layoutGuide.leftAnchor, constant: inset)]
+            }
+            let offsetAnchor = layoutGuide.leftAnchor.anchorWithOffset(to: edgeAnchor)
+            return [offsetAnchor.constraint(equalTo: layoutGuide.widthAnchor, multiplier: inset)]
+        case .right:
+            if isAbsolute {
+                return [layoutGuide.rightAnchor.constraint(equalTo: edgeAnchor, constant: inset)]
+            }
+            let offsetAnchor = edgeAnchor.anchorWithOffset(to: layoutGuide.rightAnchor)
+            return [offsetAnchor.constraint(equalTo: layoutGuide.widthAnchor, multiplier: inset)]
+        default:
+            fatalError("Unsupported reference edges")
+        }
+    }
+}
+
+/// An object that defines how to settles a panel with the intrinsic size for a content.
+@objc final public class FloatingPanelIntrinsicLayoutAnchor: NSObject, FloatingPanelLayoutAnchoring /*, NSCopying */ {
+
+    /// Returns a layout anchor with the specified offset by an absolute value and reference guide for a panel.
+    ///
+    /// The offset is an amount to offset a position of panel that displays the entire content from an edge of
+    /// the reference guide.  The edge refers to a panel positioning.
+    @objc public init(absoluteOffset offset: CGFloat, referenceGuide: FloatingPanelLayoutReferenceGuide = .safeArea) {
+        self.offset = offset
+        self.referenceGuide = referenceGuide
+        self.isAbsolute = true
+    }
+
+    /// Returns a layout anchor with the specified offset by a fractional value and reference guide for a panel.
+    ///
+    /// The offset value is a floating-point number in the range 0.0 to 1.0, where 0.0 represents the full content
+    /// is displayed and 0.5 represents the half of content is displayed.
+    @objc public init(fractionalOffset offset: CGFloat, referenceGuide: FloatingPanelLayoutReferenceGuide = .safeArea) {
+        self.offset = offset
+        self.referenceGuide = referenceGuide
+        self.isAbsolute = false
+    }
+    let offset: CGFloat
+    let isAbsolute: Bool
+
+    /// The reference rectangle area for the offset
+    @objc public let referenceGuide: FloatingPanelLayoutReferenceGuide
+}
+
+public extension FloatingPanelIntrinsicLayoutAnchor {
+    func layoutConstraints(_ vc: FloatingPanelController, for position: FloatingPanelPosition) -> [NSLayoutConstraint] {
+        let surfaceIntrinsicLength = position.mainDimension(vc.surfaceView.intrinsicContentSize)
+        let constant = isAbsolute ? surfaceIntrinsicLength - offset : surfaceIntrinsicLength * (1 - offset)
+        let layoutGuide = referenceGuide.layoutGuide(vc: vc)
+        switch position {
+        case .top:
+            return [vc.surfaceView.bottomAnchor.constraint(equalTo: layoutGuide.topAnchor, constant: constant)]
+        case .left:
+            return [vc.surfaceView.rightAnchor.constraint(equalTo: layoutGuide.leftAnchor, constant: constant)]
+        case .bottom:
+            return [vc.surfaceView.topAnchor.constraint(equalTo: layoutGuide.bottomAnchor, constant: -constant)]
+        case .right:
+            return [vc.surfaceView.leftAnchor.constraint(equalTo: layoutGuide.rightAnchor, constant: -constant)]
+        }
+    }
+}
+
+/// An object that defines how to settles a panel with a layout guide of a content view.
+@objc final public class FloatingPanelAdaptiveLayoutAnchor: NSObject, FloatingPanelLayoutAnchoring /*, NSCopying */ {
+
+    /// Returns a layout anchor with the specified offset by an absolute value, layout guide to display content and reference guide for a panel.
+    ///
+    /// The offset is an amount to offset a position of panel that displays the entire content of the specified guide from an edge of
+    /// the reference guide.  The edge refers to a panel positioning.
+    @objc public init(absoluteOffset offset: CGFloat, contentLayout: UILayoutGuide, referenceGuide: FloatingPanelLayoutReferenceGuide = .safeArea) {
+        self.offset = offset
+        self.contentLayoutGuide = contentLayout
+        self.referenceGuide = referenceGuide
+        self.isAbsolute = true
+
+    }
+
+    /// Returns a layout anchor with the specified offset by a fractional value, layout guide to display content and reference guide for a panel.
+    ///
+    /// The offset value is a floating-point number in the range 0.0 to 1.0, where 0.0 represents the full content
+    /// is displayed and 0.5 represents the half of content is displayed.
+    @objc public init(fractionalOffset offset: CGFloat, contentLayout: UILayoutGuide, referenceGuide: FloatingPanelLayoutReferenceGuide = .safeArea) {
+        self.offset = offset
+        self.contentLayoutGuide = contentLayout
+        self.referenceGuide = referenceGuide
+        self.isAbsolute = false
+    }
+    fileprivate let offset: CGFloat
+    fileprivate let isAbsolute: Bool
+    let contentLayoutGuide: UILayoutGuide
+    @objc public let referenceGuide: FloatingPanelLayoutReferenceGuide
+}
+
+public extension FloatingPanelAdaptiveLayoutAnchor {
+    func layoutConstraints(_ vc: FloatingPanelController, for position: FloatingPanelPosition) -> [NSLayoutConstraint] {
+        let layoutGuide = referenceGuide.layoutGuide(vc: vc)
+        let offsetAnchor: NSLayoutDimension
+        switch position {
+        case .top:
+            offsetAnchor = layoutGuide.topAnchor.anchorWithOffset(to: vc.surfaceView.bottomAnchor)
+        case .left:
+            offsetAnchor = layoutGuide.leftAnchor.anchorWithOffset(to: vc.surfaceView.rightAnchor)
+        case .bottom:
+            offsetAnchor = vc.surfaceView.topAnchor.anchorWithOffset(to: layoutGuide.bottomAnchor)
+        case .right:
+            offsetAnchor = vc.surfaceView.leftAnchor.anchorWithOffset(to: layoutGuide.rightAnchor)
+        }
+        if isAbsolute {
+            return [offsetAnchor.constraint(equalTo: position.mainDimensionAnchor(contentLayoutGuide), constant: -offset)]
+        } else {
+            return [offsetAnchor.constraint(equalTo: position.mainDimensionAnchor(contentLayoutGuide), multiplier: (1 - offset))]
+        }
+    }
+}
+
+extension FloatingPanelAdaptiveLayoutAnchor {
+    func distance(from dimension: CGFloat) -> CGFloat {
+        return isAbsolute ? offset : dimension * offset
+    }
+}

Sources/LayoutReferences.swift

@@ -0,0 +1,45 @@
+// Copyright 2018-Present Shin Yamamoto. All rights reserved. MIT license.
+
+import UIKit
+
+/// Constants that specify the edge of the container of a panel.
+@objc public enum FloatingPanelReferenceEdge: Int {
+    case top
+    case left
+    case bottom
+    case right
+}
+
+extension FloatingPanelReferenceEdge {
+    func inset(of insets: UIEdgeInsets) -> CGFloat {
+        switch self {
+        case .top: return insets.top
+        case .left: return insets.left
+        case .bottom: return insets.bottom
+        case .right: return insets.right
+        }
+    }
+    func mainDimension(_ size: CGSize) -> CGFloat {
+        switch self {
+        case .top, .bottom: return size.height
+        case .left, .right: return size.width
+        }
+    }
+}
+
+/// Constants that specify a layout guide to lay out a panel.
+@objc public enum FloatingPanelLayoutReferenceGuide: Int {
+    case superview = 0
+    case safeArea = 1
+}
+
+extension FloatingPanelLayoutReferenceGuide {
+    func layoutGuide(vc: UIViewController) -> LayoutGuideProvider {
+        switch self {
+        case .safeArea:
+            return vc.fp_safeAreaLayoutGuide
+        case .superview:
+            return vc.view
+        }
+    }
+}

Sources/Logger.swift

@@ -0,0 +1,100 @@
+// Copyright 2018-Present Shin Yamamoto. All rights reserved. MIT license.
+
+import Foundation
+import os.log
+
+// Must be a variable to use `hook` property in testing
+var log = {
+    return Logger()
+}()
+
+struct Logger {
+    private let osLog: OSLog
+    private let s = DispatchSemaphore(value: 1)
+
+    enum Level: Int, Comparable {
+        case debug = 0
+        case info = 1
+        case warning = 2
+        case error = 3
+
+        var displayName: String {
+            switch self {
+            case .debug:
+                return "Debug:"
+            case .info:
+                return "Info:"
+            case .warning:
+                return "Warning:"
+            case .error:
+                return "Error:"
+            }
+        }
+        @available(iOS 10.0, *)
+        var osLogType: OSLogType {
+            switch self {
+            case .debug: return .debug
+            case .info: return .info
+            case .warning: return .default
+            case .error: return .error
+            }
+        }
+
+        static func < (lhs: Logger.Level, rhs: Logger.Level) -> Bool {
+            return lhs.rawValue < rhs.rawValue
+        }
+    }
+
+    typealias Hook = ((String, Level) -> Void)
+    var hook: Hook?
+
+    fileprivate init() {
+        osLog = OSLog(subsystem: "com.scenee.FloatingPanel", category: "FloatingPanel")
+    }
+
+    private func log(_ level: Level, _ message: Any, _ arguments: [Any], tag: String, function: String, line: UInt) {
+        _ = s.wait(timeout: .now() + 0.033)
+        defer { s.signal() }
+
+        let extraMessage: String = arguments.map({ String(describing: $0) }).joined(separator: " ")
+        let _tag = tag.isEmpty ? "" : "\(tag):"
+        let log: String = {
+            switch level {
+            case .debug:
+                return "\(level.displayName)\(_tag) \(message) \(extraMessage) (\(function):\(line))"
+            default:
+                return "\(level.displayName)\(_tag) \(message) \(extraMessage)"
+            }
+        }()
+
+        hook?(log, level)
+
+        os_log("%{public}@", log: osLog, type: level.osLogType, log)
+    }
+
+    private func getPrettyFunction(_ function: String, _ file: String) -> String {
+        if let filename = file.split(separator: "/").last {
+            return filename + ":" + function
+        } else {
+            return file + ":" + function
+        }
+    }
+
+    func debug(_ log: Any, _ arguments: Any..., tag: String = "", function: String = #function, file: String  = #file, line: UInt = #line) {
+        #if __FP_LOG
+        self.log(.debug, log, arguments, tag: tag, function: getPrettyFunction(function, file), line: line)
+        #endif
+    }
+
+    func info(_ log: Any, _ arguments: Any..., tag: String = "",  function: String = #function, file: String  = #file, line: UInt = #line) {
+        self.log(.info, log, arguments, tag: tag, function: getPrettyFunction(function, file), line: line)
+    }
+
+    func warning(_ log: Any, _ arguments: Any..., function: String = #function, file: String  = #file, line: UInt = #line) {
+        self.log(.warning, log, arguments, tag: "", function: getPrettyFunction(function, file), line: line)
+    }
+
+    func error(_ log: Any, _ arguments: Any..., function: String = #function, file: String  = #file, line: UInt = #line) {
+        self.log(.error, log, arguments, tag: "", function: getPrettyFunction(function, file), line: line)
+    }
+}

Sources/PassthroughView.swift

@@ -0,0 +1,17 @@
+// Copyright 2018-Present Shin Yamamoto. All rights reserved. MIT license.
+
+import UIKit
+
+@objc(FloatingPanelPassthroughView)
+class PassthroughView: UIView {
+    public weak var eventForwardingView: UIView?
+    public override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
+        let hitView = super.hitTest(point, with: event)
+        switch hitView {
+        case self:
+            return eventForwardingView?.hitTest(self.convert(point, to: eventForwardingView), with: event)
+        default:
+            return hitView
+        }
+    }
+}

Sources/Position.swift

@@ -0,0 +1,50 @@
+// Copyright 2018-Present Shin Yamamoto. All rights reserved. MIT license.
+
+import UIKit
+
+/// Constants describing the position of a panel in a screen
+@objc public enum FloatingPanelPosition: Int {
+    case top
+    case left
+    case bottom
+    case right
+}
+
+extension FloatingPanelPosition {
+    func mainLocation(_ point: CGPoint) -> CGFloat {
+        switch self {
+        case .top, .bottom: return point.y
+        case .left, .right: return point.x
+        }
+    }
+
+    func mainDimension(_ size: CGSize) -> CGFloat {
+        switch self {
+        case .top, .bottom: return size.height
+        case .left, .right: return size.width
+        }
+    }
+
+    func mainDimensionAnchor(_ layoutGuide: LayoutGuideProvider) -> NSLayoutDimension {
+        switch self {
+        case .top, .bottom: return layoutGuide.heightAnchor
+        case .left, .right: return layoutGuide.widthAnchor
+        }
+    }
+
+    func crossDimension(_ size: CGSize) -> CGFloat {
+        switch self {
+        case .top, .bottom: return size.width
+        case .left, .right: return size.height
+        }
+    }
+
+    func inset(_ insets: UIEdgeInsets) -> CGFloat {
+        switch self {
+        case .top: return insets.top
+        case .left: return insets.left
+        case .bottom: return insets.bottom
+        case .right: return insets.right
+        }
+    }
+}

Sources/State.swift

@@ -0,0 +1,64 @@
+// Copyright 2018-Present Shin Yamamoto. All rights reserved. MIT license.
+
+import Foundation
+
+/// An object that represents the display state of a panel in a screen.
+@objc
+open class FloatingPanelState: NSObject, NSCopying, RawRepresentable {
+    public typealias RawValue = String
+
+    required public init?(rawValue: RawValue) {
+        self.order = 0
+        self.rawValue = rawValue
+        super.init()
+    }
+
+    @objc
+    public init(rawValue: RawValue, order: Int) {
+        self.rawValue = rawValue
+        self.order = order
+        super.init()
+    }
+
+    /// The corresponding value of the raw type.
+    public let rawValue: RawValue
+    /// The sorting order for states
+    public let order: Int
+
+    public func copy(with zone: NSZone? = nil) -> Any {
+        return self
+    }
+
+    public override var description: String {
+        return rawValue
+    }
+
+    public override var debugDescription: String {
+        return "<FloatingPanel.FloatingPanelState: \(Unmanaged.passUnretained(self).toOpaque())>"
+    }
+
+    /// A panel state indicates the entire panel is shown.
+    @objc(Full) public static let full: FloatingPanelState = FloatingPanelState(rawValue: "full", order: 1000)
+    /// A panel state indicates the half of a panel is shown.
+    @objc(Half) public static let half: FloatingPanelState = FloatingPanelState(rawValue: "half", order: 500)
+    /// A panel state indicates the tip of a panel is shown.
+    @objc(Tip) public static let tip: FloatingPanelState = FloatingPanelState(rawValue: "tip", order: 100)
+    /// A panel state indicates it is hidden.
+    @objc(Hidden) public static let hidden: FloatingPanelState = FloatingPanelState(rawValue: "hidden", order: 0)
+}
+
+extension FloatingPanelState {
+    func next(in states: [FloatingPanelState]) -> FloatingPanelState {
+        if let index = states.firstIndex(of: self), states.indices.contains(index + 1) {
+            return states[index + 1]
+        }
+        return self
+    }
+
+    func pre(in states: [FloatingPanelState]) -> FloatingPanelState {
+        if let index = states.firstIndex(of: self), states.indices.contains(index - 1) {
+            return states[index - 1]
+        }
+        return self
+    }
+}

Sources/SurfaceView.swift

@@ -0,0 +1,440 @@
+// Copyright 2018-Present Shin Yamamoto. All rights reserved. MIT license.
+
+import UIKit
+
+/// An object for customizing the appearance of a surface view
+@objc(FloatingPanelSurfaceAppearance)
+@objcMembers
+public class SurfaceAppearance: NSObject {
+
+    /// An object that represents information to render a shadow
+    @objc(FloatingPanelSurfaceAppearanceShadow)
+    public class Shadow: NSObject {
+        /// A Boolean indicating whether a shadow is displayed.
+        @objc
+        public var hidden: Bool = false
+
+        /// The color of a shadow.
+        @objc
+        public var color: UIColor = .black
+
+        /// The offset (in points) of a shadow.
+        @objc
+        public var offset: CGSize = CGSize(width: 0.0, height: 1.0)
+
+        /// The opacity of a shadow.
+        @objc
+        public var opacity: Float = 0.2
+
+        /// The blur radius (in points) used to render a shadow.
+        @objc
+        public var radius: CGFloat = 3
+
+        /// The inflated amount of a shadow prior to applying the blur.
+        @objc
+        public var spread: CGFloat = 0
+
+    }
+    /// The background color of a surface view
+    public var backgroundColor: UIColor? = {
+        if #available(iOS 13, *) {
+            return UIColor.systemBackground
+        } else {
+            return UIColor.white
+        }
+    }()
+
+    /// The radius to use when drawing the top rounded corners.
+    ///
+    /// `self.contentView` is masked with the top rounded corners automatically on iOS 11 and later.
+    /// On iOS 10, they are not automatically masked because of a UIVisualEffectView issue. See https://forums.developer.apple.com/thread/50854
+    public var cornerRadius: CGFloat = 0.0
+
+    /// Defines the curve used for rendering the rounded corners of the layer.
+    ///
+    /// Defaults to `.circular`.
+    @available(iOS 13.0, *)
+    public lazy var cornerCurve: CALayerCornerCurve = .circular
+
+    /// An array of shadows used to create drop shadows underneath a surface view.
+    public var shadows: [Shadow] = [Shadow()]
+
+    /// The border width of a surface view.
+    public var borderColor: UIColor?
+
+    /// The border color of a surface view.
+    public var borderWidth: CGFloat = 0.0
+}
+
+/// A view that presents a surface interface in a panel.
+@objc(FloatingPanelSurfaceView)
+@objcMembers
+public class SurfaceView: UIView {
+    /// A `FloatingPanelGrabberView` object displayed at the top of the surface view.
+    ///
+    /// To use a custom grabber, hide this and then add it to the surface view at appropriate point.
+    public let grabberHandle = GrabberView()
+
+    /// Offset of the grabber handle from the interactive edge.
+    public var grabberHandlePadding: CGFloat = 6.0 { didSet {
+        setNeedsUpdateConstraints()
+    } }
+
+    /// The offset from the move edge to prevent the content scroll
+    public var grabberAreaOffset: CGFloat = 36.0
+
+    /// The grabber handle size
+    ///
+    /// On left/right positioned panel the width dimension is used as the height of `grabberHandle`, and vice versa.
+    public var grabberHandleSize: CGSize = CGSize(width: 36.0, height: 5.0) { didSet {
+        setNeedsUpdateConstraints()
+    } }
+
+    /// The content view to be assigned a view of the content view controller of `FloatingPanelController`
+    public weak var contentView: UIView?
+
+    /// The content insets specifying the insets around the content view.
+    public var contentPadding: UIEdgeInsets = .zero {
+        didSet {
+            // Needs update constraints
+            self.setNeedsUpdateConstraints()
+        }
+    }
+
+    public override var backgroundColor: UIColor? {
+        get { return appearance.backgroundColor }
+        set { appearance.backgroundColor = newValue; setNeedsLayout() }
+    }
+
+    /// The appearance settings for a surface view.
+    public var appearance = SurfaceAppearance() { didSet {
+        shadowLayers = appearance.shadows.map { _ in CAShapeLayer() }
+        setNeedsLayout()
+    }}
+
+    /// The margins to use when laying out the container view wrapping content.
+    public var containerMargins: UIEdgeInsets = .zero { didSet {
+        setNeedsUpdateConstraints()
+    } }
+
+    /// The view that displays an actual surface shape.
+    ///
+    /// It renders the background color, border line and top rounded corners,
+    /// specified by other properties. The reason why they're not be applied to
+    /// a content view directly is because it avoids any side-effects to the
+    /// content view.
+    public let containerView: UIView = UIView()
+
+    var containerOverflow: CGFloat = 0.0 { // Must not call setNeedsLayout()
+        didSet {
+            // Calling setNeedsUpdateConstraints() is necessary to fix a layout break
+            // when the contentMode is changed after laying out a panel, for instance,
+            // after calling viewDidAppear(_:) of the parent view controller.
+            setNeedsUpdateConstraints()
+        }
+    }
+
+    var position: FloatingPanelPosition = .bottom {
+        didSet {
+            guard position != oldValue else { return }
+            NSLayoutConstraint.deactivate([grabberHandleEdgePaddingConstraint,
+                                           grabberHandleCenterConstraint,
+                                           grabberHandleWidthConstraint,
+                                           grabberHandleHeightConstraint])
+            switch position {
+            case .top:
+                grabberHandleEdgePaddingConstraint = grabberHandle.bottomAnchor.constraint(equalTo: bottomAnchor, constant: -grabberHandlePadding)
+                grabberHandleCenterConstraint = grabberHandle.centerXAnchor.constraint(equalTo: centerXAnchor)
+                grabberHandleWidthConstraint = grabberHandle.widthAnchor.constraint(equalToConstant: grabberHandleSize.width)
+                grabberHandleHeightConstraint = grabberHandle.heightAnchor.constraint(equalToConstant: grabberHandleSize.height)
+            case .left:
+                grabberHandleEdgePaddingConstraint = grabberHandle.rightAnchor.constraint(equalTo: rightAnchor, constant: -grabberHandlePadding)
+                grabberHandleCenterConstraint = grabberHandle.centerYAnchor.constraint(equalTo: centerYAnchor)
+                grabberHandleWidthConstraint = grabberHandle.widthAnchor.constraint(equalToConstant: grabberHandleSize.height)
+                grabberHandleHeightConstraint = grabberHandle.heightAnchor.constraint(equalToConstant: grabberHandleSize.width)
+            case .bottom:
+                grabberHandleEdgePaddingConstraint = grabberHandle.topAnchor.constraint(equalTo: topAnchor, constant: grabberHandlePadding)
+                grabberHandleCenterConstraint = grabberHandle.centerXAnchor.constraint(equalTo: centerXAnchor)
+                grabberHandleWidthConstraint = grabberHandle.widthAnchor.constraint(equalToConstant: grabberHandleSize.width)
+                grabberHandleHeightConstraint = grabberHandle.heightAnchor.constraint(equalToConstant: grabberHandleSize.height)
+            case .right:
+                grabberHandleEdgePaddingConstraint = grabberHandle.leftAnchor.constraint(equalTo: leftAnchor, constant: grabberHandlePadding)
+                grabberHandleCenterConstraint = grabberHandle.centerYAnchor.constraint(equalTo: centerYAnchor)
+                grabberHandleWidthConstraint = grabberHandle.widthAnchor.constraint(equalToConstant: grabberHandleSize.height)
+                grabberHandleHeightConstraint = grabberHandle.heightAnchor.constraint(equalToConstant: grabberHandleSize.width)
+            }
+            NSLayoutConstraint.activate([grabberHandleEdgePaddingConstraint,
+                                         grabberHandleCenterConstraint,
+                                         grabberHandleWidthConstraint,
+                                         grabberHandleHeightConstraint])
+            setNeedsUpdateConstraints()
+        }
+    }
+
+    var grabberAreaFrame: CGRect {
+        switch position {
+        case .top:
+            return CGRect(origin: .init(x: bounds.minX, y: bounds.maxY - grabberAreaOffset),
+                          size: .init(width: bounds.width, height: grabberAreaOffset))
+        case .left:
+            return CGRect(origin: .init(x: bounds.maxX - grabberAreaOffset, y: bounds.minY),
+                          size: .init(width: grabberAreaOffset, height: bounds.height))
+        case .bottom:
+            return CGRect(origin: CGPoint(x: bounds.minX, y: bounds.minY),
+                          size: CGSize(width: bounds.width, height: grabberAreaOffset))
+        case .right:
+            return CGRect(origin: .init(x: bounds.minX, y: bounds.minY),
+                          size: .init(width: grabberAreaOffset, height: bounds.height))
+        }
+    }
+
+    private lazy var containerViewTopConstraint = containerView.topAnchor.constraint(equalTo: topAnchor, constant: 0.0)
+    private lazy var containerViewLeftConstraint = containerView.leftAnchor.constraint(equalTo: leftAnchor, constant: 0.0)
+    private lazy var containerViewBottomConstraint = containerView.bottomAnchor.constraint(equalTo: bottomAnchor, constant: 0.0)
+    private lazy var containerViewRightConstraint = containerView.rightAnchor.constraint(equalTo: rightAnchor, constant: 0.0)
+
+    /// The content view's top constraint
+    private var contentViewTopConstraint: NSLayoutConstraint?
+    /// The content view's left constraint
+    private var contentViewLeftConstraint: NSLayoutConstraint?
+    /// The content view's right constraint
+    private var contentViewRightConstraint: NSLayoutConstraint?
+    /// The content view's bottom constraint
+    private var contentViewBottomConstraint: NSLayoutConstraint?
+
+    private lazy var grabberHandleWidthConstraint = grabberHandle.widthAnchor.constraint(equalToConstant: grabberHandleSize.width)
+    private lazy var grabberHandleHeightConstraint = grabberHandle.heightAnchor.constraint(equalToConstant: grabberHandleSize.height)
+    private lazy var grabberHandleCenterConstraint =  grabberHandle.centerXAnchor.constraint(equalTo: centerXAnchor)
+    private lazy var grabberHandleEdgePaddingConstraint = grabberHandle.topAnchor.constraint(equalTo: topAnchor, constant: grabberHandlePadding)
+
+    private var shadowLayers: [CALayer] = [] {
+        willSet {
+            for shadowLayer in shadowLayers {
+                shadowLayer.removeFromSuperlayer()
+            }
+        }
+        didSet {
+            for shadowLayer in shadowLayers {
+                layer.insertSublayer(shadowLayer, at: 0)
+            }
+        }
+    }
+
+    public override class var requiresConstraintBasedLayout: Bool { return true }
+
+    override init(frame: CGRect) {
+        super.init(frame: frame)
+        addSubViews()
+    }
+
+    required public init?(coder aDecoder: NSCoder) {
+        super.init(coder: aDecoder)
+        addSubViews()
+    }
+
+    private func addSubViews() {
+        super.backgroundColor = .clear
+        self.clipsToBounds = false
+
+        addSubview(containerView)
+        containerView.translatesAutoresizingMaskIntoConstraints = false
+        NSLayoutConstraint.activate([
+            containerViewTopConstraint,
+            containerViewLeftConstraint,
+            containerViewBottomConstraint,
+            containerViewRightConstraint,
+        ].map {
+            $0.identifier = "FloatingPanel-surface-container"
+            return $0;
+        })
+
+        addSubview(grabberHandle)
+        grabberHandle.translatesAutoresizingMaskIntoConstraints = false
+        NSLayoutConstraint.activate([
+            grabberHandleEdgePaddingConstraint,
+            grabberHandleCenterConstraint,
+            grabberHandleWidthConstraint,
+            grabberHandleHeightConstraint,
+        ].map {
+            $0.identifier = "FloatingPanel-surface-grabber"
+            return $0;
+        })
+
+        shadowLayers = appearance.shadows.map { _ in CALayer() }
+    }
+
+    public override func updateConstraints() {
+        switch position {
+        case .top:
+            containerViewTopConstraint.constant = (containerMargins.top == 0) ? -containerOverflow : containerMargins.top
+            containerViewLeftConstraint.constant = containerMargins.left
+            containerViewRightConstraint.constant = -containerMargins.right
+            containerViewBottomConstraint.constant = -containerMargins.bottom
+        case .left:
+            containerViewTopConstraint.constant = containerMargins.top
+            containerViewLeftConstraint.constant = (containerMargins.left == 0) ? -containerOverflow : containerMargins.left
+            containerViewRightConstraint.constant = -containerMargins.right
+            containerViewBottomConstraint.constant = -containerMargins.bottom
+        case .bottom:
+            containerViewTopConstraint.constant = containerMargins.top
+            containerViewLeftConstraint.constant = containerMargins.left
+            containerViewRightConstraint.constant = -containerMargins.right
+            containerViewBottomConstraint.constant = (containerMargins.bottom == 0) ? containerOverflow : -containerMargins.bottom
+        case .right:
+            containerViewTopConstraint.constant = containerMargins.top
+            containerViewLeftConstraint.constant = containerMargins.left
+            containerViewRightConstraint.constant = (containerMargins.right == 0) ? containerOverflow : -containerMargins.right
+            containerViewBottomConstraint.constant = -containerMargins.bottom
+        }
+
+        contentViewTopConstraint?.constant = containerMargins.top + contentPadding.top
+        contentViewLeftConstraint?.constant = containerMargins.left + contentPadding.left
+        contentViewRightConstraint?.constant = containerMargins.right + contentPadding.right
+        contentViewBottomConstraint?.constant = containerMargins.bottom + contentPadding.bottom
+
+        switch position {
+        case .top, .left:
+            grabberHandleEdgePaddingConstraint.constant = -grabberHandlePadding
+        case .bottom, .right:
+            grabberHandleEdgePaddingConstraint.constant = grabberHandlePadding
+        }
+
+        switch position {
+        case .top, .bottom:
+            grabberHandleWidthConstraint.constant = grabberHandleSize.width
+            grabberHandleHeightConstraint.constant = grabberHandleSize.height
+        case .left, .right:
+            grabberHandleWidthConstraint.constant = grabberHandleSize.height
+            grabberHandleHeightConstraint.constant = grabberHandleSize.width
+       }
+
+        super.updateConstraints()
+    }
+
+    public override func layoutSubviews() {
+        super.layoutSubviews()
+        log.debug("surface view frame = \(frame)")
+
+        containerView.backgroundColor = appearance.backgroundColor
+
+        updateCornerRadius()
+        updateShadow()
+        updateBorder()
+
+        grabberHandle.layer.cornerRadius = grabberHandleSize.height / 2
+    }
+
+    public override var intrinsicContentSize: CGSize {
+        let fittingSize = UIView.layoutFittingCompressedSize
+        let contentSize = contentView?.systemLayoutSizeFitting(fittingSize) ?? .zero
+        return CGSize(width: containerMargins.horizontalInset + contentPadding.horizontalInset + contentSize.width,
+                      height: containerMargins.verticalInset + contentPadding.verticalInset + contentSize.height)
+    }
+
+    private func updateShadow() {
+        // Disable shadow animation when the surface's frame jumps to a new value.
+        CATransaction.begin()
+        CATransaction.setDisableActions(true)
+        for (i, shadow) in appearance.shadows.enumerated() {
+            let shadowLayer = shadowLayers[i]
+
+            shadowLayer.backgroundColor = UIColor.clear.cgColor
+            shadowLayer.frame = layer.bounds
+
+            let spread = shadow.spread
+            let shadowRect = containerView.frame.insetBy(dx: -spread, dy: -spread)
+            let shadowPath = UIBezierPath.path(roundedRect: shadowRect,
+                                               appearance: appearance)
+            shadowLayer.shadowPath = shadowPath.cgPath
+            shadowLayer.shadowColor = shadow.color.cgColor
+            shadowLayer.shadowOffset = shadow.offset
+            // A shadow.radius value isn't manipulated by a scale(i.e. the display scale). It should be applied to the value by itself.
+            shadowLayer.shadowRadius = shadow.radius
+            shadowLayer.shadowOpacity = shadow.opacity
+
+            let mask = CAShapeLayer()
+            let path = UIBezierPath.path(roundedRect: containerView.frame,
+                                         appearance: appearance)
+            let size = window?.bounds.size ?? CGSize(width: 1000.0, height: 1000.0)
+            path.append(UIBezierPath(rect: layer.bounds.insetBy(dx: -size.width,
+                                                                dy: -size.height)))
+            mask.fillRule = .evenOdd
+            mask.path = path.cgPath
+            if #available(iOS 13.0, *) {
+                containerView.layer.cornerCurve = appearance.cornerCurve
+                mask.cornerCurve = appearance.cornerCurve
+            }
+            shadowLayer.mask = mask
+        }
+        CATransaction.commit()
+    }
+
+    private func updateCornerRadius() {
+        containerView.layer.cornerRadius = appearance.cornerRadius
+        guard containerView.layer.cornerRadius != 0.0 else {
+            containerView.layer.masksToBounds = false
+            return
+        }
+        containerView.layer.masksToBounds = true
+        if position.inset(containerMargins) != 0 {
+            if #available(iOS 11, *) {
+                containerView.layer.maskedCorners = [.layerMinXMinYCorner, .layerMaxXMinYCorner,
+                                                     .layerMinXMaxYCorner, .layerMaxXMaxYCorner]
+            }
+            return
+        }
+        if #available(iOS 11, *) {
+            // Don't use `contentView.clipToBounds` because it prevents content view from expanding the height of a subview of it
+            // for the bottom overflow like Auto Layout settings of UIVisualEffectView in Main.storyboard of Example/Maps.
+            // Because the bottom of contentView must be fit to the bottom of a screen to work the `safeLayoutGuide` of a content VC.
+            switch position {
+            case .top:
+                containerView.layer.maskedCorners = [.layerMinXMaxYCorner, .layerMaxXMaxYCorner]
+            case .left:
+                containerView.layer.maskedCorners = [.layerMaxXMinYCorner, .layerMaxXMaxYCorner]
+            case .bottom:
+                containerView.layer.maskedCorners = [.layerMinXMinYCorner, .layerMaxXMinYCorner]
+            case .right:
+                containerView.layer.maskedCorners = [.layerMinXMinYCorner, .layerMinXMaxYCorner]
+            }
+        } else {
+            // Can't use `containerView.layer.mask` because of a UIVisualEffectView issue in iOS 10, https://forums.developer.apple.com/thread/50854
+            // Instead, a user should display rounding corners appropriately.
+        }
+    }
+
+    private func updateBorder() {
+        containerView.layer.borderColor = appearance.borderColor?.cgColor
+        containerView.layer.borderWidth = appearance.borderWidth
+    }
+
+    func set(contentView: UIView) {
+        containerView.addSubview(contentView)
+        self.contentView = contentView
+        /* contentView.frame = bounds */ // MUST NOT: Because the top safe area inset of a content VC will be incorrect.
+        contentView.translatesAutoresizingMaskIntoConstraints = false
+
+        let topConstraint = contentView.topAnchor.constraint(equalTo: topAnchor, constant: containerMargins.top + contentPadding.top)
+        let leftConstraint = contentView.leftAnchor.constraint(equalTo: leftAnchor, constant: containerMargins.left + contentPadding.left)
+        let rightConstraint = rightAnchor.constraint(equalTo: contentView.rightAnchor, constant: containerMargins.right + contentPadding.right)
+        let bottomConstraint = bottomAnchor.constraint(equalTo: contentView.bottomAnchor, constant: containerMargins.bottom + contentPadding.bottom)
+        NSLayoutConstraint.activate([
+            topConstraint,
+            leftConstraint,
+            rightConstraint,
+            bottomConstraint,
+        ].map {
+            $0.priority = .required - 1;
+            $0.identifier = "FloatingPanel-surface-content"
+            return $0;
+        })
+        self.contentViewTopConstraint = topConstraint
+        self.contentViewLeftConstraint = leftConstraint
+        self.contentViewRightConstraint = rightConstraint
+        self.contentViewBottomConstraint = bottomConstraint
+    }
+
+    func hasStackView() -> Bool {
+        return contentView?.subviews.reduce(false) { $0 || ($1 is UIStackView) } ?? false
+    }
+}

Sources/Transitioning.swift

@@ -0,0 +1,146 @@
+// Copyright 2018-Present Shin Yamamoto. All rights reserved. MIT license.
+
+import UIKit
+
+class ModalTransition: NSObject, UIViewControllerTransitioningDelegate {
+    func animationController(forPresented presented: UIViewController,
+                             presenting: UIViewController,
+                             source: UIViewController) -> UIViewControllerAnimatedTransitioning? {
+        return ModalPresentTransition()
+    }
+
+    func animationController(forDismissed dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning? {
+        return ModalDismissTransition()
+    }
+
+    func presentationController(forPresented presented: UIViewController, presenting: UIViewController?, source: UIViewController) -> UIPresentationController? {
+        return PresentationController(presentedViewController: presented, presenting: presenting)
+    }
+}
+
+class PresentationController: UIPresentationController {
+    override func presentationTransitionWillBegin() {
+        // Must call here even if duplicating on in containerViewWillLayoutSubviews()
+        // Because it let the panel present correctly with the presentation animation
+        addFloatingPanel()
+    }
+
+    override func presentationTransitionDidEnd(_ completed: Bool) {
+        // For non-animated presentation
+        if let fpc = presentedViewController as? FloatingPanelController, fpc.state == .hidden {
+            fpc.show(animated: false, completion: nil)
+        }
+    }
+
+    override func dismissalTransitionDidEnd(_ completed: Bool) {
+        if let fpc = presentedViewController as? FloatingPanelController {
+            // For non-animated dismissal
+            if fpc.state != .hidden {
+                fpc.hide(animated: false, completion: nil)
+            }
+            fpc.view.removeFromSuperview()
+        }
+    }
+
+    override func containerViewWillLayoutSubviews() {
+        guard
+            let fpc = presentedViewController as? FloatingPanelController,
+            /**
+             This condition fixes https://github.com/SCENEE/FloatingPanel/issues/369.
+             The issue is that this method is called in presenting a
+             UIImagePickerViewController and then a FloatingPanelController
+             view is added unnecessarily.
+             */
+            fpc.presentedViewController == nil
+            else { return }
+
+        /*
+         * Layout the views managed by `FloatingPanelController` here for the
+         * sake of the presentation and dismissal modally from the controller.
+         */
+        addFloatingPanel()
+
+        // Forward touch events to the presenting view controller
+        (fpc.view as? PassthroughView)?.eventForwardingView = presentingViewController.view
+    }
+
+    @objc func handleBackdrop(tapGesture: UITapGestureRecognizer) {
+        presentedViewController.dismiss(animated: true, completion: nil)
+    }
+
+    private func addFloatingPanel() {
+        guard
+            let containerView = self.containerView,
+            let fpc = presentedViewController as? FloatingPanelController
+            else { fatalError() }
+
+        containerView.addSubview(fpc.view)
+        fpc.view.frame = containerView.bounds
+        fpc.view.autoresizingMask = [.flexibleWidth, .flexibleHeight]
+    }
+}
+
+class ModalPresentTransition: NSObject, UIViewControllerAnimatedTransitioning {
+    func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
+        guard
+            let fpc = transitionContext?.viewController(forKey: .to) as? FloatingPanelController
+        else { fatalError()}
+
+        let animator = fpc.animatorForPresenting(to: fpc.layout.initialState)
+        return TimeInterval(animator.duration)
+    }
+
+    func interruptibleAnimator(using transitionContext: UIViewControllerContextTransitioning) -> UIViewImplicitlyAnimating {
+        guard
+            let fpc = transitionContext.viewController(forKey: .to) as? FloatingPanelController
+        else { fatalError() }
+
+        if let animator = fpc.transitionAnimator {
+            return animator
+        }
+
+        fpc.suspendTransitionAnimator(true)
+        fpc.show(animated: true) { [weak fpc] in
+            fpc?.suspendTransitionAnimator(false)
+            transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
+        }
+        return fpc.transitionAnimator!
+    }
+
+    func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
+        self.interruptibleAnimator(using: transitionContext).startAnimation()
+    }
+}
+
+class ModalDismissTransition: NSObject, UIViewControllerAnimatedTransitioning {
+    func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
+        guard
+            let fpc = transitionContext?.viewController(forKey: .from) as? FloatingPanelController
+        else { fatalError()}
+
+        let animator = fpc.animatorForDismissing(with: .zero)
+        return TimeInterval(animator.duration)
+    }
+
+    func interruptibleAnimator(using transitionContext: UIViewControllerContextTransitioning) -> UIViewImplicitlyAnimating {
+        guard
+            let fpc = transitionContext.viewController(forKey: .from) as? FloatingPanelController
+        else { fatalError() }
+
+        if let animator = fpc.transitionAnimator {
+            return animator
+        }
+
+        fpc.suspendTransitionAnimator(true)
+        fpc.hide(animated: true) { [weak fpc] in
+            fpc?.suspendTransitionAnimator(false)
+            transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
+        }
+        return fpc.transitionAnimator!
+    }
+
+    func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
+        self.interruptibleAnimator(using: transitionContext).startAnimation()
+    }
+}
+

Sources/UIExtensions.swift

@@ -0,0 +1,270 @@
+// Copyright 2018-Present Shin Yamamoto. All rights reserved. MIT license.
+
+import UIKit
+
+internal func displayTrunc(_ v: CGFloat, by s: CGFloat) -> CGFloat {
+    let base = (1 / s)
+    let t = v.rounded(.down)
+    return t + ((v - t) / base).rounded(.toNearestOrAwayFromZero) * base
+}
+
+internal func displayEqual(_ lhs: CGFloat, _ rhs: CGFloat, by displayScale: CGFloat) -> Bool {
+    return displayTrunc(lhs, by: displayScale) == displayTrunc(rhs, by: displayScale)
+}
+
+protocol LayoutGuideProvider {
+    var topAnchor: NSLayoutYAxisAnchor { get }
+    var leftAnchor: NSLayoutXAxisAnchor { get }
+    var bottomAnchor: NSLayoutYAxisAnchor { get }
+    var rightAnchor: NSLayoutXAxisAnchor { get }
+    var widthAnchor: NSLayoutDimension { get }
+    var heightAnchor: NSLayoutDimension { get }
+}
+extension UILayoutGuide: LayoutGuideProvider {}
+extension UIView: LayoutGuideProvider {}
+
+private class CustomLayoutGuide: LayoutGuideProvider {
+    let topAnchor: NSLayoutYAxisAnchor
+    let leftAnchor: NSLayoutXAxisAnchor
+    let bottomAnchor: NSLayoutYAxisAnchor
+    let rightAnchor: NSLayoutXAxisAnchor
+    let widthAnchor: NSLayoutDimension
+    let heightAnchor: NSLayoutDimension
+    init(topAnchor: NSLayoutYAxisAnchor,
+         leftAnchor: NSLayoutXAxisAnchor,
+         bottomAnchor: NSLayoutYAxisAnchor,
+         rightAnchor: NSLayoutXAxisAnchor,
+         widthAnchor: NSLayoutDimension,
+         heightAnchor: NSLayoutDimension) {
+        self.topAnchor = topAnchor
+        self.leftAnchor = leftAnchor
+        self.bottomAnchor = bottomAnchor
+        self.rightAnchor = rightAnchor
+        self.widthAnchor = widthAnchor
+        self.heightAnchor = heightAnchor
+    }
+}
+
+extension UIViewController {
+    @objc var fp_safeAreaInsets: UIEdgeInsets {
+        if #available(iOS 11.0, *) {
+            return view.safeAreaInsets
+        } else {
+            return UIEdgeInsets(top: topLayoutGuide.length,
+                                left: 0.0,
+                                bottom: bottomLayoutGuide.length,
+                                right: 0.0)
+        }
+    }
+
+    var fp_safeAreaLayoutGuide: LayoutGuideProvider {
+        if #available(iOS 11.0, *) {
+            return view!.safeAreaLayoutGuide
+        } else {
+            return CustomLayoutGuide(topAnchor: topLayoutGuide.bottomAnchor,
+                                     leftAnchor: view.leftAnchor,
+                                     bottomAnchor: bottomLayoutGuide.topAnchor,
+                                     rightAnchor: view.rightAnchor,
+                                     widthAnchor: view.widthAnchor,
+                                     heightAnchor: topLayoutGuide.bottomAnchor.anchorWithOffset(to: bottomLayoutGuide.topAnchor))
+        }
+    }
+}
+
+// The reason why UIView has no extensions of safe area insets and top/bottom guides
+// is for iOS10 compatibility.
+extension UIView {
+    var fp_safeAreaLayoutGuide: LayoutGuideProvider {
+        if #available(iOS 11.0, *) {
+            return safeAreaLayoutGuide
+        } else {
+            return self
+        }
+    }
+
+    var presentationFrame: CGRect {
+        return layer.presentation()?.frame ?? frame
+    }
+
+    /// Returns non-zero displayScale
+    ///
+    /// On iOS 11 or earlier the `traitCollection.displayScale` of a view can be
+    /// 0.0(indicating unspecified) when its view hasn't been added yet into a view tree in a window.
+    /// So this method returns `UIScreen.main` scale if the scale value is zero, for testing mainly.
+    var fp_displayScale: CGFloat {
+        let ret = traitCollection.displayScale
+        if ret == 0.0 {
+            return UIScreen.main.scale
+        }
+        return ret
+    }
+}
+
+extension UIView {
+    func disableAutoLayout() {
+        let frame = self.frame
+        translatesAutoresizingMaskIntoConstraints = true
+        self.frame = frame
+    }
+    func enableAutoLayout() {
+        translatesAutoresizingMaskIntoConstraints = false
+    }
+
+    static func performWithLinear(startTime: Double = 0.0, relativeDuration: Double = 1.0, _ animations: @escaping (() -> Void)) {
+        UIView.animateKeyframes(withDuration: 0.0, delay: 0.0, options: [.calculationModeCubic], animations: {
+            UIView.addKeyframe(withRelativeStartTime: startTime, relativeDuration: relativeDuration, animations: animations)
+        }, completion: nil)
+    }
+}
+
+#if __FP_LOG
+extension UIGestureRecognizer.State: CustomDebugStringConvertible {
+    public var debugDescription: String {
+        switch self {
+        case .began: return "began"
+        case .changed: return "changed"
+        case .failed: return "failed"
+        case .cancelled: return "cancelled"
+        case .ended: return "ended"
+        case .possible: return "possible"
+        @unknown default: return ""
+        }
+    }
+}
+#endif
+
+extension UIScrollView {
+    var isLocked: Bool {
+        return !showsVerticalScrollIndicator && !bounces &&  isDirectionalLockEnabled
+    }
+    var fp_contentInset: UIEdgeInsets {
+        if #available(iOS 11.0, *) {
+            return adjustedContentInset
+        } else {
+            return contentInset
+        }
+    }
+    var fp_contentOffsetMax: CGPoint {
+        return CGPoint(x: max((contentSize.width + fp_contentInset.right) - bounds.width, 0.0),
+                       y: max((contentSize.height + fp_contentInset.bottom) - bounds.height, 0.0))
+    }
+}
+
+extension UISpringTimingParameters {
+    public convenience init(decelerationRate: CGFloat, frequencyResponse: CGFloat, initialVelocity: CGVector = .zero) {
+        let dampingRatio = CoreGraphics.log(decelerationRate) / (-4 * .pi * 0.001)
+        self.init(dampingRatio: dampingRatio, frequencyResponse: frequencyResponse, initialVelocity: initialVelocity)
+    }
+
+    public convenience init(dampingRatio: CGFloat, frequencyResponse: CGFloat, initialVelocity: CGVector = .zero) {
+        let mass = 1 as CGFloat
+        let stiffness = pow(2 * .pi / frequencyResponse, 2) * mass
+        let damp = 4 * .pi * dampingRatio * mass / frequencyResponse
+        self.init(mass: mass, stiffness: stiffness, damping: damp, initialVelocity: initialVelocity)
+    }
+}
+
+extension CGPoint {
+    static var leastNonzeroMagnitude: CGPoint {
+        return CGPoint(x: CGFloat.leastNonzeroMagnitude, y: CGFloat.leastNonzeroMagnitude)
+    }
+
+    static func + (lhs: CGPoint, rhs: CGPoint) -> CGPoint {
+        return CGPoint(x: lhs.x + rhs.x, y: lhs.y + rhs.y)
+    }
+
+    static func - (lhs: CGPoint, rhs: CGPoint) -> CGPoint {
+        return CGPoint(x: lhs.x - rhs.x, y: lhs.y - rhs.y)
+    }
+
+    static prefix func - (point: CGPoint) -> CGPoint {
+        return CGPoint(x: -point.x, y: -point.y)
+    }
+}
+
+extension NSLayoutConstraint {
+    static func activate(constraint: NSLayoutConstraint?) {
+        guard let constraint = constraint else { return }
+        self.activate([constraint])
+    }
+    static func deactivate(constraint: NSLayoutConstraint?) {
+        guard let constraint = constraint else { return }
+        self.deactivate([constraint])
+    }
+}
+
+extension UIEdgeInsets {
+    var horizontalInset: CGFloat {
+        return self.left + self.right
+    }
+    var verticalInset: CGFloat {
+        return self.top + self.bottom
+    }
+}
+
+extension UIBezierPath {
+    static func path(roundedRect rect: CGRect, appearance: SurfaceAppearance) -> UIBezierPath {
+        let cornerRadius = appearance.cornerRadius;
+        if #available(iOS 13.0, *) {
+            if appearance.cornerCurve == .circular {
+                let path = UIBezierPath()
+                let start = CGPoint(x: rect.minX + cornerRadius, y: rect.minY)
+
+                path.move(to: start)
+
+                path.addLine(to: CGPoint(x: rect.maxX - cornerRadius, y: rect.minY))
+                if cornerRadius > 0 {
+                    path .addArc(withCenter: CGPoint(x: rect.maxX - cornerRadius,
+                                                     y: rect.minY + cornerRadius),
+                                 radius: cornerRadius,
+                                 startAngle: -0.5 * .pi,
+                                 endAngle: 0,
+                                 clockwise: true)
+                }
+
+                path.addLine(to: CGPoint(x: rect.maxX, y: rect.maxY - cornerRadius))
+
+                if cornerRadius > 0 {
+                    path.addArc(withCenter: CGPoint(x: rect.maxX - cornerRadius,
+                                                    y: rect.maxY - cornerRadius),
+                                radius: cornerRadius,
+                                startAngle: 0,
+                                endAngle: .pi * 0.5,
+                                clockwise: true)
+                }
+
+                path.addLine(to: CGPoint(x: rect.minX + cornerRadius, y: rect.maxY))
+
+                if cornerRadius > 0 {
+                    path.addArc(withCenter: CGPoint(x: rect.minX + cornerRadius,
+                                                    y: rect.maxY - cornerRadius),
+                                radius: cornerRadius,
+                                startAngle: .pi * 0.5,
+                                endAngle: .pi,
+                                clockwise: true)
+                }
+
+                path.addLine(to: CGPoint(x: rect.minX, y: rect.minY + cornerRadius))
+
+                if cornerRadius > 0 {
+                    path.addArc(withCenter: CGPoint(x: rect.minX + cornerRadius,
+                                                    y: rect.minY + cornerRadius),
+                                radius: cornerRadius,
+                                startAngle: .pi,
+                                endAngle: .pi * 1.5,
+                                clockwise: true)
+                }
+
+                path.addLine(to: start)
+
+                path.close()
+
+                return path
+            }
+        }
+        return UIBezierPath(roundedRect: rect,
+                            byRoundingCorners: [.allCorners],
+                            cornerRadii: CGSize(width: cornerRadius,
+                                                height: cornerRadius))
+    }
+}

Tests/ControllerTests.swift

@@ -0,0 +1,352 @@
+// Copyright 2018 the FloatingPanel authors. All rights reserved. MIT license.
+
+import XCTest
+@testable import FloatingPanel
+
+class ControllerTests: XCTestCase {
+    override func setUp() {}
+    override func tearDown() {}
+
+    func test_warningRetainCycle() {
+        let exp = expectation(description: "Warning retain cycle")
+        exp.expectedFulfillmentCount = 2 // For layout & behavior logs
+        log.hook = {(log, level) in
+            if log.contains("A memory leak will occur by a retain cycle because") {
+                XCTAssert(level == .warning)
+                exp.fulfill()
+            }
+        }
+        let myVC = MyZombieViewController(nibName: nil, bundle: nil)
+        myVC.loadViewIfNeeded()
+        wait(for: [exp], timeout: 10)
+    }
+
+    func test_addPanel() {
+        guard let rootVC = UIApplication.shared.keyWindow?.rootViewController else { fatalError() }
+        let fpc = FloatingPanelController()
+        fpc.addPanel(toParent: rootVC)
+        XCTAssertEqual(fpc.surfaceLocation.y, fpc.surfaceLocation(for: .half).y)
+        fpc.move(to: .tip, animated: false)
+        XCTAssertEqual(fpc.surfaceLocation.y, fpc.surfaceLocation(for: .tip).y)
+    }
+
+    @available(iOS 12.0, *)
+    func test_updateLayout_willTransition() {
+        class MyDelegate: FloatingPanelControllerDelegate {
+            func floatingPanel(_ vc: FloatingPanelController, layoutFor newCollection: UITraitCollection) -> FloatingPanelLayout {
+                if newCollection.userInterfaceStyle == .dark {
+                    XCTFail()
+                }
+                return FloatingPanelBottomLayout()
+            }
+        }
+        let myDelegate = MyDelegate()
+        let fpc = FloatingPanelController(delegate: myDelegate)
+        let traitCollection = UITraitCollection(traitsFrom: [fpc.traitCollection,
+                                                             UITraitCollection(userInterfaceStyle: .dark)])
+        XCTAssertEqual(traitCollection.userInterfaceStyle, .dark)
+    }
+
+    func test_moveTo() {
+        let delegate = FloatingPanelTestDelegate()
+        let fpc = FloatingPanelController(delegate: delegate)
+        XCTAssertEqual(delegate.position, .hidden)
+        fpc.showForTest()
+        XCTAssertEqual(delegate.position, .half)
+
+        fpc.hide()
+        XCTAssertEqual(delegate.position, .hidden)
+        
+        fpc.move(to: .full, animated: false)
+        XCTAssertEqual(fpc.state, .full)
+        XCTAssertEqual(delegate.position, .full)
+        XCTAssertEqual(fpc.surfaceLocation.y, fpc.surfaceLocation(for: .full).y)
+
+        fpc.move(to: .half, animated: false)
+        XCTAssertEqual(fpc.state, .half)
+        XCTAssertEqual(delegate.position, .half)
+
+        XCTAssertEqual(fpc.surfaceLocation, fpc.surfaceLocation(for: .half))
+
+        fpc.move(to: .tip, animated: false)
+        XCTAssertEqual(fpc.state, .tip)
+        XCTAssertEqual(delegate.position, .tip)
+        XCTAssertEqual(fpc.surfaceLocation.y, fpc.surfaceLocation(for: .tip).y)
+
+        fpc.move(to: .hidden, animated: false)
+        XCTAssertEqual(fpc.state, .hidden)
+        XCTAssertEqual(delegate.position, .hidden)
+        XCTAssertEqual(fpc.surfaceLocation.y, fpc.surfaceLocation(for: .hidden).y)
+
+        XCTContext.runActivity(named: "move to full(animated)") { act in
+            let exp = expectation(description: act.name)
+            fpc.move(to: .full, animated: true) {
+                XCTAssertEqual(fpc.surfaceLocation.y, fpc.surfaceLocation(for: .full).y)
+                exp.fulfill()
+            }
+            XCTAssertEqual(fpc.state, .full)
+            XCTAssertEqual(delegate.position, .full)
+            wait(for: [exp], timeout: 1.0)
+        }
+
+        XCTContext.runActivity(named: "move to half(animated)") { act in
+            let exp = expectation(description: act.name)
+            fpc.move(to: .half, animated: true) {
+                XCTAssertEqual(fpc.surfaceLocation, fpc.surfaceLocation(for: .half))
+                exp.fulfill()
+            }
+            XCTAssertEqual(fpc.state, .half)
+            XCTAssertEqual(delegate.position, .half)
+            wait(for: [exp], timeout: 1.0)
+        }
+
+        XCTContext.runActivity(named: "move to tip(animated)") { act in
+            let exp = expectation(description: act.name)
+            fpc.move(to: .tip, animated: true) {
+                XCTAssertEqual(fpc.surfaceLocation.y, fpc.surfaceLocation(for: .tip).y)
+                exp.fulfill()
+            }
+            XCTAssertEqual(fpc.state, .tip)
+            XCTAssertEqual(delegate.position, .tip)
+            wait(for: [exp], timeout: 1.0)
+        }
+
+        fpc.move(to: .hidden, animated: true)
+        XCTAssertEqual(fpc.state, .hidden)
+        XCTAssertEqual(delegate.position, .hidden)
+        XCTAssertEqual(fpc.surfaceLocation.y, fpc.surfaceLocation(for: .hidden).y)
+    }
+
+    func test_moveTo_bottomEdge() {
+        class MyFloatingPanelTop2BottomLayout: FloatingPanelTop2BottomTestLayout {
+            override var initialState: FloatingPanelState { return .half }
+        }
+        let delegate = FloatingPanelTestDelegate()
+        let fpc = FloatingPanelController(delegate: delegate)
+        fpc.layout = MyFloatingPanelTop2BottomLayout()
+        XCTAssertEqual(delegate.position, .hidden)
+        fpc.showForTest()
+        XCTAssertEqual(delegate.position, .half)
+
+        fpc.hide()
+        XCTAssertEqual(delegate.position, .hidden)
+
+        fpc.move(to: .full, animated: false)
+        XCTAssertEqual(fpc.state, .full)
+        XCTAssertEqual(delegate.position, .full)
+        XCTAssertEqual(fpc.surfaceLocation.y, fpc.surfaceLocation(for: .full).y)
+
+        fpc.move(to: .half, animated: false)
+        XCTAssertEqual(fpc.state, .half)
+        XCTAssertEqual(delegate.position, .half)
+        XCTAssertEqual(fpc.surfaceLocation.y, fpc.surfaceLocation(for: .half).y)
+
+        fpc.move(to: .tip, animated: false)
+        XCTAssertEqual(fpc.state, .tip)
+        XCTAssertEqual(delegate.position, .tip)
+        XCTAssertEqual(fpc.surfaceLocation.y, fpc.surfaceLocation(for: .tip).y)
+
+        fpc.move(to: .hidden, animated: false)
+        XCTAssertEqual(fpc.state, .hidden)
+        XCTAssertEqual(delegate.position, .hidden)
+        XCTAssertEqual(fpc.surfaceLocation.y, fpc.surfaceLocation(for: .hidden).y)
+
+        XCTContext.runActivity(named: "move to full(animated)") { act in
+            let exp = expectation(description: act.name)
+            fpc.move(to: .full, animated: true) {
+                XCTAssertEqual(fpc.surfaceLocation.y, fpc.surfaceLocation(for: .full).y)
+                exp.fulfill()
+            }
+            XCTAssertEqual(fpc.state, .full)
+            XCTAssertEqual(delegate.position, .full)
+            wait(for: [exp], timeout: 1.0)
+        }
+
+        XCTContext.runActivity(named: "move to half(animated)") { act in
+            let exp = expectation(description: act.name)
+            fpc.move(to: .half, animated: true) {
+                XCTAssertEqual(fpc.surfaceLocation, fpc.surfaceLocation(for: .half))
+                exp.fulfill()
+            }
+            XCTAssertEqual(fpc.state, .half)
+            XCTAssertEqual(delegate.position, .half)
+            wait(for: [exp], timeout: 1.0)
+        }
+
+        XCTContext.runActivity(named: "move to tip(animated)") { act in
+            let exp = expectation(description: act.name)
+            fpc.move(to: .tip, animated: true) {
+                XCTAssertEqual(fpc.surfaceLocation.y, fpc.surfaceLocation(for: .tip).y)
+                exp.fulfill()
+            }
+            XCTAssertEqual(fpc.state, .tip)
+            XCTAssertEqual(delegate.position, .tip)
+            wait(for: [exp], timeout: 1.0)
+        }
+
+        fpc.move(to: .hidden, animated: true)
+        XCTAssertEqual(fpc.state, .hidden)
+        XCTAssertEqual(delegate.position, .hidden)
+        XCTAssertEqual(fpc.surfaceLocation.y, fpc.surfaceLocation(for: .hidden).y)
+    }
+    
+    func test_moveWithNearbyPosition() {
+        let delegate = FloatingPanelTestDelegate()
+        let fpc = FloatingPanelController(delegate: delegate)
+        XCTAssertEqual(delegate.position, .hidden)
+        fpc.showForTest()
+        
+        XCTAssertEqual(fpc.nearbyState, .half)
+        
+        fpc.hide()
+        XCTAssertEqual(fpc.nearbyState, .tip)
+        
+        fpc.move(to: .full, animated: false)
+        XCTAssertEqual(fpc.nearbyState, .full)
+        XCTAssertEqual(fpc.surfaceView.frame.minY, fpc.surfaceLocation(for: .full).y)
+    }
+
+    func test_moveTo_didMoveDelegate() {
+        let delegate = FloatingPanelTestDelegate()
+        let fpc = FloatingPanelController(delegate: delegate)
+        XCTAssertEqual(delegate.position, .hidden)
+        fpc.showForTest()
+
+        XCTContext.runActivity(named: "move(to:animated:false") { act in
+            let exp = expectation(description: act.name)
+            exp.expectedFulfillmentCount = 1
+            var count = 0
+            delegate.didMoveCallback = { _ in
+                count += 1
+                exp.fulfill()
+            }
+            fpc.move(to: .full, animated: false)
+            wait(for: [exp], timeout: 1.0)
+
+            XCTAssertEqual(count, 1)
+        }
+
+        XCTContext.runActivity(named: "move(to:animated:true)") { act in
+            let exp = expectation(description: act.name)
+            exp.assertForOverFulfill = false
+            exp.expectedFulfillmentCount = 1
+            var count = 0
+            delegate.didMoveCallback = { _ in
+                count += 1
+            }
+            fpc.move(to: .half, animated: true) {
+                exp.fulfill()
+            }
+            wait(for: [exp], timeout: 1.0)
+
+            XCTAssertGreaterThan(count, 1)
+        }
+
+        XCTContext.runActivity(named: "move(to:animated:false) with animation") { act in
+            let exp = expectation(description: act.name)
+            exp.expectedFulfillmentCount = 1
+            var count = 0
+            delegate.didMoveCallback = { _ in
+                count += 1
+            }
+            UIView.animate(withDuration: 0.3) {
+                fpc.move(to: .full, animated: false) {
+                    exp.fulfill()
+                }
+            }
+            wait(for: [exp], timeout: 1.0)
+
+            XCTAssertEqual(count, 1)
+        }
+
+        XCTContext.runActivity(named: "move(to:animated:true) with animation") { act in
+            let exp = expectation(description: act.name)
+            exp.assertForOverFulfill = false
+            exp.expectedFulfillmentCount = 1
+            var count = 0
+            delegate.didMoveCallback = { _ in
+                count += 1
+            }
+            UIView.animate(withDuration: 0.3) {
+                fpc.move(to: .half, animated: true) {
+                    exp.fulfill()
+                }
+            }
+            wait(for: [exp], timeout: 1.0)
+
+            XCTAssertGreaterThan(count, 1)
+        }
+    }
+
+    func test_originSurfaceY() {
+        let fpc = FloatingPanelController(delegate: nil)
+        fpc.loadViewIfNeeded()
+        fpc.view.frame = CGRect(x: 0, y: 0, width: 375, height: 667)
+        fpc.show(animated: false, completion: nil)
+
+        fpc.move(to: .full, animated: false)
+        XCTAssertEqual(fpc.surfaceLocation, fpc.surfaceLocation(for: .full))
+        fpc.move(to: .half, animated: false)
+        XCTAssertEqual(fpc.surfaceLocation, fpc.surfaceLocation(for: .half))
+        fpc.move(to: .tip, animated: false)
+        XCTAssertEqual(fpc.surfaceLocation, fpc.surfaceLocation(for: .tip))
+        fpc.move(to: .hidden, animated: false)
+        XCTAssertEqual(fpc.surfaceLocation, fpc.surfaceLocation(for: .hidden))
+    }
+
+    func test_contentMode() {
+        let fpc = FloatingPanelController(delegate: nil)
+        fpc.loadViewIfNeeded()
+        fpc.view.frame = CGRect(x: 0, y: 0, width: 375, height: 667)
+        fpc.show(animated: false, completion: nil)
+
+        fpc.contentMode = .static
+
+        fpc.move(to: .full, animated: false)
+        XCTAssertEqual(fpc.surfaceView.frame.height, fpc.view.bounds.height - fpc.surfaceLocation(for: .full).y)
+        fpc.move(to: .half, animated: false)
+        XCTAssertEqual(fpc.surfaceView.frame.height, fpc.view.bounds.height - fpc.surfaceLocation(for: .full).y)
+        fpc.move(to: .tip, animated: false)
+        XCTAssertEqual(fpc.surfaceView.frame.height, fpc.view.bounds.height - fpc.surfaceLocation(for: .full).y)
+
+        fpc.contentMode = .fitToBounds
+
+        fpc.move(to: .full, animated: false)
+        XCTAssertEqual(fpc.surfaceView.frame.height, fpc.view.bounds.height - fpc.surfaceLocation(for: .full).y)
+        fpc.move(to: .half, animated: false)
+        print(1 / fpc.surfaceView.fp_displayScale)
+        XCTAssertEqual(fpc.surfaceView.frame.height, fpc.view.bounds.height - fpc.surfaceLocation(for: .half).y)
+        fpc.move(to: .tip, animated: false)
+        XCTAssertEqual(fpc.surfaceView.frame.height, fpc.view.bounds.height - fpc.surfaceLocation(for: .tip).y)
+    }
+}
+
+private class MyZombieViewController: UIViewController, FloatingPanelLayout, FloatingPanelBehavior, FloatingPanelControllerDelegate {
+    var fpc: FloatingPanelController?
+    override func viewDidLoad() {
+        fpc = FloatingPanelController(delegate: self)
+        fpc?.addPanel(toParent: self)
+        fpc?.layout = self
+        fpc?.behavior = self
+    }
+    var position: FloatingPanelPosition {
+        return .bottom
+    }
+    var initialState: FloatingPanelState {
+        return .half
+    }
+
+    var anchors: [FloatingPanelState : FloatingPanelLayoutAnchoring] {
+        return [
+            .full: FloatingPanelLayoutAnchor(absoluteInset: UIScreen.main.bounds.height == 667.0 ? 18.0 : 16.0,
+                                             edge: .top,
+                                             referenceGuide: .superview),
+            .half: FloatingPanelLayoutAnchor(absoluteInset: 250.0,
+                                             edge: .bottom,
+                                             referenceGuide: .superview),
+            .tip: FloatingPanelLayoutAnchor(absoluteInset: 60.0,
+                                            edge: .bottom,
+                                            referenceGuide: .superview),
+        ]
+    }
+}

Tests/CoreTests.swift

@@ -0,0 +1,738 @@
+// Copyright 2018 the FloatingPanel authors. All rights reserved. MIT license.
+
+import XCTest
+@testable import FloatingPanel
+
+class CoreTests: XCTestCase {
+    override func setUp() {}
+    override func tearDown() {}
+
+    func test_scrolllock() {
+        let fpc = FloatingPanelController()
+
+        let contentVC1 = UITableViewController(nibName: nil, bundle: nil)
+        XCTAssertEqual(contentVC1.tableView.showsVerticalScrollIndicator, true)
+        XCTAssertEqual(contentVC1.tableView.bounces, true)
+        fpc.set(contentViewController: contentVC1)
+        fpc.track(scrollView: contentVC1.tableView)
+        fpc.showForTest()
+
+        XCTAssertEqual(fpc.state, .half)
+        XCTAssertEqual(contentVC1.tableView.showsVerticalScrollIndicator, false)
+        XCTAssertEqual(contentVC1.tableView.bounces, false)
+
+        fpc.move(to: .full, animated: false)
+        XCTAssertEqual(contentVC1.tableView.showsVerticalScrollIndicator, true)
+        XCTAssertEqual(contentVC1.tableView.bounces, true)
+
+        fpc.move(to: .tip, animated: false)
+        XCTAssertEqual(contentVC1.tableView.showsVerticalScrollIndicator, false)
+        XCTAssertEqual(contentVC1.tableView.bounces, false)
+
+        let exp1 = expectation(description: "move to full with animation")
+        fpc.move(to: .full, animated: true) {
+            XCTAssertEqual(contentVC1.tableView.showsVerticalScrollIndicator, true)
+            XCTAssertEqual(contentVC1.tableView.bounces, true)
+            exp1.fulfill()
+        }
+        wait(for: [exp1], timeout: 1.0)
+
+        let exp2 = expectation(description: "move to tip with animation")
+        fpc.move(to: .tip, animated: false) {
+            XCTAssertEqual(contentVC1.tableView.showsVerticalScrollIndicator, false)
+            XCTAssertEqual(contentVC1.tableView.bounces, false)
+            exp2.fulfill()
+        }
+        wait(for: [exp2], timeout: 1.0)
+
+        // Reset the content vc
+        let contentVC2 = UITableViewController(nibName: nil, bundle: nil)
+        XCTAssertEqual(contentVC2.tableView.showsVerticalScrollIndicator, true)
+        XCTAssertEqual(contentVC2.tableView.bounces, true)
+        fpc.set(contentViewController: contentVC2)
+        fpc.track(scrollView: contentVC2.tableView)
+        fpc.show(animated: false, completion: nil)
+        XCTAssertEqual(fpc.state, .half)
+        XCTAssertEqual(contentVC2.tableView.showsVerticalScrollIndicator, false)
+        XCTAssertEqual(contentVC2.tableView.bounces, false)
+    }
+
+    func test_getBackdropAlpha_1positions() {
+        class FloatingPanelLayout1Positions: FloatingPanelLayout {
+            let initialState: FloatingPanelState = .full
+            let position: FloatingPanelPosition = .bottom
+            var anchors: [FloatingPanelState : FloatingPanelLayoutAnchoring] {
+                return [.full: FloatingPanelLayoutAnchor(absoluteInset: 20.0, edge: .top, referenceGuide: .superview)]
+            }
+        }
+
+        let delegate = FloatingPanelTestDelegate()
+        let fpc = FloatingPanelController(delegate: delegate)
+        fpc.layout = FloatingPanelLayout1Positions()
+
+        fpc.showForTest()
+
+        let fullPos = fpc.surfaceLocation(for: .full).y
+
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: fullPos - 100.0, with: -100.0), 0.3)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: fullPos, with: 0), 0.3)
+        XCTAssertLessThan(fpc.floatingPanel.getBackdropAlpha(at: fullPos + 100.0, with: 100.0), 0.3)
+    }
+
+    func test_getBackdropAlpha_1positionsWithInitialHidden() {
+        class FloatingPanelLayout2Positions: FloatingPanelTestLayout {
+            override var initialState: FloatingPanelState { .hidden }
+            override var anchors: [FloatingPanelState : FloatingPanelLayoutAnchoring] {
+                return [
+                    .full: FloatingPanelLayoutAnchor(absoluteInset: fullInset, edge: .top, referenceGuide: referenceGuide),
+                ]
+            }
+        }
+        let delegate = FloatingPanelTestDelegate()
+        let fpc = FloatingPanelController(delegate: delegate)
+        fpc.layout = FloatingPanelLayout2Positions()
+
+        fpc.showForTest()
+
+        let fullPos = fpc.surfaceLocation(for: .full).y
+        let hiddenPos = fpc.surfaceLocation(for: .hidden).y
+
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: fullPos - 100.0, with:  -100.0), 0.3)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: fullPos, with: 0.0), 0.3)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: hiddenPos, with: 100.0), 0.0)
+    }
+
+    func test_getBackdropAlpha_2positions() {
+        class FloatingPanelLayout2Positions: FloatingPanelLayout {
+            let initialState: FloatingPanelState = .half
+            let position: FloatingPanelPosition = .bottom
+            var anchors: [FloatingPanelState : FloatingPanelLayoutAnchoring] {
+                return [
+                    .full: FloatingPanelLayoutAnchor(absoluteInset: 20.0, edge: .top, referenceGuide: .superview),
+                    .half: FloatingPanelLayoutAnchor(absoluteInset: 250.0, edge: .bottom, referenceGuide: .superview),
+                ]
+            }
+        }
+
+        let delegate = FloatingPanelTestDelegate()
+        let fpc = FloatingPanelController(delegate: delegate)
+        fpc.layout = FloatingPanelLayout2Positions()
+
+        fpc.showForTest()
+
+        let fullPos = fpc.surfaceLocation(for: .full).y
+        let halfPos = fpc.surfaceLocation(for: .half).y
+        let distance1 = abs(halfPos - fullPos)
+
+        fpc.move(to: .full, animated: false)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: fullPos, with: 0.0), 0.3)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: fullPos + distance1 * 0.5, with: distance1), 0.3 * 0.5)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: halfPos, with: distance1), 0.0)
+
+        fpc.move(to: .half, animated: false)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: halfPos, with: 0.0), 0.0)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: fullPos + distance1 * 0.5, with: -0.5 * distance1), 0.3 * 0.5)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: fullPos, with: -1 * distance1), 0.3)
+    }
+
+    func test_getBackdropAlpha_2positionsWithHidden() {
+        class FloatingPanelLayout2Positions: FloatingPanelTestLayout {
+            override var initialState: FloatingPanelState { .hidden }
+            override var anchors: [FloatingPanelState : FloatingPanelLayoutAnchoring] {
+                return [
+                    .full: FloatingPanelLayoutAnchor(absoluteInset: fullInset, edge: .top, referenceGuide: referenceGuide),
+                    .hidden: FloatingPanelLayoutAnchor(absoluteInset: 0.0, edge: .bottom, referenceGuide: referenceGuide),
+                ]
+            }
+        }
+        let delegate = FloatingPanelTestDelegate()
+        let fpc = FloatingPanelController(delegate: delegate)
+        fpc.layout = FloatingPanelLayout2Positions()
+
+        fpc.showForTest()
+
+        let fullPos = fpc.surfaceLocation(for: .full).y
+        let hiddenPos = fpc.surfaceLocation(for: .hidden).y
+
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: fullPos - 100.0, with:  -100.0), 0.3)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: fullPos, with: 0.0), 0.3)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: hiddenPos, with: 100.0), 0.0)
+    }
+
+    func test_getBackdropAlpha_3positions() {
+        let fpc = FloatingPanelController()
+        fpc.showForTest()
+
+        let fullPos = fpc.surfaceLocation(for: .full).y
+        let halfPos = fpc.surfaceLocation(for: .half).y
+        let tipPos = fpc.surfaceLocation(for: .tip).y
+        let distance1 = abs(halfPos - fullPos)
+        let distance2 = abs(tipPos - halfPos)
+
+        fpc.move(to: .full, animated: false)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: fullPos, with: 0.0), 0.3)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: fullPos + distance1 * 0.5, with: distance1 * 0.5), 0.3 * 0.5)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: halfPos, with: distance1), 0.0)
+
+        fpc.move(to: .half, animated: false)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: halfPos, with: 0.0), 0.0)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: fullPos + distance1 * 0.5, with: -0.5 * distance1), 0.3 * 0.5)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: fullPos, with: -1 * distance1), 0.3)
+
+        fpc.move(to: .tip, animated: false)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: tipPos, with: 0.0), 0.0)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: halfPos + distance2 * 0.5, with: -0.5 * distance2), 0.0)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: halfPos, with: -1 * distance2), 0.0)
+    }
+
+    func test_targetPosition_1positions() {
+        class FloatingPanelLayout1Positions: FloatingPanelLayout {
+            let initialState: FloatingPanelState = .full
+            let position: FloatingPanelPosition = .bottom
+            var anchors: [FloatingPanelState : FloatingPanelLayoutAnchoring] {
+                return [.full: FloatingPanelLayoutAnchor(absoluteInset: 20.0, edge: .top, referenceGuide: .superview)]
+            }
+        }
+
+        let delegate = FloatingPanelTestDelegate()
+        let fpc = FloatingPanelController(delegate: delegate)
+        fpc.layout = FloatingPanelLayout1Positions()
+
+        fpc.showForTest()
+
+        let fullPos = fpc.surfaceLocation(for: .full).y
+
+        fpc.move(to: .full, animated: false)
+        assertTargetPosition(fpc.floatingPanel, with: [
+            (#line, fullPos - 10.0, CGPoint(x: 0.0, y: 1000.0), .full), // redirect
+            (#line, fullPos, CGPoint(x: 0.0, y: -1000.0), .full), // redirect
+            (#line, fullPos, CGPoint(x: 0.0, y: -100.0), .full), // redirect
+            (#line, fullPos, CGPoint(x: 0.0, y: 0.0), .full),
+            (#line, fullPos, CGPoint(x: 0.0, y: 100.0), .full), // redirect
+            (#line, fullPos, CGPoint(x: 0.0, y: 1000.0), .full), // redirect
+            (#line, fullPos + 10.0, CGPoint(x: 0.0, y: 100.0), .full), // redirect
+            ])
+    }
+
+    func test_targetPosition_2positions() {
+        class FloatingPanelLayout2Positions: FloatingPanelLayout {
+            let initialState: FloatingPanelState = .half
+            let position: FloatingPanelPosition = .bottom
+            var anchors: [FloatingPanelState : FloatingPanelLayoutAnchoring] {
+                return [
+                    .full: FloatingPanelLayoutAnchor(absoluteInset: 20.0, edge: .top, referenceGuide: .superview),
+                    .half: FloatingPanelLayoutAnchor(absoluteInset: 250.0, edge: .bottom, referenceGuide: .superview),
+                ]
+            }
+        }
+
+        let delegate = FloatingPanelTestDelegate()
+        let fpc = FloatingPanelController(delegate: delegate)
+        fpc.layout = FloatingPanelLayout2Positions()
+
+        fpc.showForTest()
+
+        let fullPos = fpc.surfaceLocation(for: .full).y
+        let halfPos = fpc.surfaceLocation(for: .half).y
+
+        fpc.move(to: .full, animated: false)
+        assertTargetPosition(fpc.floatingPanel, with: [
+            (#line, fullPos - 10.0, CGPoint(x: 0.0, y: 1000.0), .half), // project to half
+            (#line, fullPos, CGPoint(x: 0.0, y: -1000.0), .full), // redirect
+            (#line, fullPos, CGPoint(x: 0.0, y: -100.0), .full),
+            (#line, fullPos, CGPoint(x: 0.0, y: 0.0), .full),
+            (#line, fullPos, CGPoint(x: 0.0, y: 100.0), .full),
+            (#line, fullPos, CGPoint(x: 0.0, y: 1000.0), .half), // project to half
+            (#line, fullPos + 10.0, CGPoint(x: 0.0, y: 100.0), .full), // redirect
+            (#line, halfPos - 10.0, CGPoint(x: 0.0, y: -100.0), .half), // redirect
+            (#line, halfPos, CGPoint(x: 0.0, y: -1000.0), .full),  // project to full
+            (#line, halfPos, CGPoint(x: 0.0, y: -100.0), .half),
+            (#line, halfPos, CGPoint(x: 0.0, y: 0.0), .half),
+            (#line, halfPos, CGPoint(x: 0.0, y: 100.0), .half),
+            (#line, halfPos, CGPoint(x: 0.0, y: 1000.0), .half), // redirect
+            (#line, halfPos + 10.0, CGPoint(x: 0.0, y: -1000.0), .full), // project to full
+            ])
+        fpc.move(to: .half, animated: false)
+        assertTargetPosition(fpc.floatingPanel, with: [
+            (#line, fullPos - 10.0, CGPoint(x: 0.0, y: 1000.0), .half), // project to half
+            (#line, fullPos, CGPoint(x: 0.0, y: -1000.0), .full), // redirect
+            (#line, fullPos, CGPoint(x: 0.0, y: -100.0), .full),
+            (#line, fullPos, CGPoint(x: 0.0, y: 0.0), .full),
+            (#line, fullPos, CGPoint(x: 0.0, y: 100.0), .full),
+            (#line, fullPos, CGPoint(x: 0.0, y: 1000.0), .half), // project to half
+            (#line, fullPos + 10.0, CGPoint(x: 0.0, y: 100.0), .full), // redirect
+            (#line, halfPos - 10.0, CGPoint(x: 0.0, y: -100.0), .half), // redirect
+            (#line, halfPos, CGPoint(x: 0.0, y: -1000.0), .full),  // project to full
+            (#line, halfPos, CGPoint(x: 0.0, y: -100.0), .half),
+            (#line, halfPos, CGPoint(x: 0.0, y: 0.0), .half),
+            (#line, halfPos, CGPoint(x: 0.0, y: 100.0), .half),
+            (#line, halfPos, CGPoint(x: 0.0, y: 1000.0), .half), // redirect
+            (#line, halfPos + 10.0, CGPoint(x: 0.0, y: -1000.0), .full), // project to full
+            ])
+    }
+
+    func test_targetPosition_2positionsWithHidden() {
+        class FloatingPanelLayout2Positions: FloatingPanelLayout {
+            let initialState: FloatingPanelState = .hidden
+            let position: FloatingPanelPosition = .bottom
+            var anchors: [FloatingPanelState : FloatingPanelLayoutAnchoring] {
+                return [
+                    .full: FloatingPanelLayoutAnchor(absoluteInset: 20.0, edge: .top, referenceGuide: .superview),
+                    .hidden: FloatingPanelLayoutAnchor(absoluteInset: 0, edge: .bottom, referenceGuide: .superview),
+                ]
+            }
+        }
+
+        let delegate = FloatingPanelTestDelegate()
+        let fpc = FloatingPanelController(delegate: delegate)
+        fpc.layout = FloatingPanelLayout2Positions()
+
+        fpc.showForTest()
+
+        let fullPos = fpc.surfaceLocation(for: .full).y
+        let hiddenPos = fpc.surfaceLocation(for: .hidden).y
+
+        fpc.move(to: .full, animated: false)
+        assertTargetPosition(fpc.floatingPanel, with: [
+            (#line, fullPos - 10.0, CGPoint(x: 0.0, y: 1000.0), .hidden), // project to hidden
+            (#line, fullPos, CGPoint(x: 0.0, y: -1000.0), .full), // redirect
+            (#line, fullPos, CGPoint(x: 0.0, y: -100.0), .full),
+            (#line, fullPos, CGPoint(x: 0.0, y: 0.0), .full),
+            (#line, fullPos, CGPoint(x: 0.0, y: 100.0), .full),
+            (#line, fullPos, CGPoint(x: 0.0, y: 1000.0), .hidden), // project to hidden
+            (#line, fullPos + 10.0, CGPoint(x: 0.0, y: 100.0), .full), // redirect
+            (#line, hiddenPos - 10.0, CGPoint(x: 0.0, y: -100.0), .hidden), // redirect
+            (#line, hiddenPos, CGPoint(x: 0.0, y: -1000.0), .full),  // project to full
+            (#line, hiddenPos, CGPoint(x: 0.0, y: -100.0), .hidden),
+            (#line, hiddenPos, CGPoint(x: 0.0, y: 0.0), .hidden),
+            (#line, hiddenPos, CGPoint(x: 0.0, y: 100.0), .hidden),
+            (#line, hiddenPos, CGPoint(x: 0.0, y: 1000.0), .hidden), // redirect
+            (#line, hiddenPos + 10.0, CGPoint(x: 0.0, y: -1000.0), .full), // project to full
+            ])
+        fpc.move(to: .hidden, animated: false)
+        assertTargetPosition(fpc.floatingPanel, with: [
+            (#line, fullPos - 10.0, CGPoint(x: 0.0, y: 1000.0), .hidden), // project to hidden
+            (#line, fullPos, CGPoint(x: 0.0, y: -1000.0), .full), // redirect
+            (#line, fullPos, CGPoint(x: 0.0, y: -100.0), .full),
+            (#line, fullPos, CGPoint(x: 0.0, y: 0.0), .full),
+            (#line, fullPos, CGPoint(x: 0.0, y: 100.0), .full),
+            (#line, fullPos, CGPoint(x: 0.0, y: 1000.0), .hidden), // project to hidden
+            (#line, fullPos + 10.0, CGPoint(x: 0.0, y: 100.0), .full), // redirect
+            (#line, hiddenPos - 10.0, CGPoint(x: 0.0, y: -100.0), .hidden), // redirect
+            (#line, hiddenPos, CGPoint(x: 0.0, y: -1000.0), .full),  // project to full
+            (#line, hiddenPos, CGPoint(x: 0.0, y: -100.0), .hidden),
+            (#line, hiddenPos, CGPoint(x: 0.0, y: 0.0), .hidden),
+            (#line, hiddenPos, CGPoint(x: 0.0, y: 100.0), .hidden),
+            (#line, hiddenPos, CGPoint(x: 0.0, y: 1000.0), .hidden), // redirect
+            (#line, hiddenPos + 10.0, CGPoint(x: 0.0, y: -1000.0), .full), // project to full
+            ])
+    }
+
+    func test_targetPosition_3positionsFromFull() {
+        let delegate = FloatingPanelTestDelegate()
+        let fpc = FloatingPanelController(delegate: delegate)
+        fpc.layout = FloatingPanelLayout3Positions()
+
+        fpc.showForTest()
+
+        let fullPos = fpc.surfaceLocation(for: .full).y
+        let halfPos = fpc.surfaceLocation(for: .half).y
+        let tipPos = fpc.surfaceLocation(for: .tip).y
+        // From .full
+        fpc.move(to: .full, animated: false)
+        assertTargetPosition(fpc.floatingPanel, with: [
+            (#line, fullPos - 500.0, CGPoint(x: 0.0, y: -100.0), .full), // far from topMostState
+            (#line, fullPos - 500.0, CGPoint(x: 0.0, y: 0.0), .full), // far from topMostState
+            (#line, fullPos - 500.0, CGPoint(x: 0.0, y: 100.0), .full), // far from topMostState
+            (#line, fullPos - 10.0, CGPoint(x: 0.0, y: 3000.0), .half), // block projecting to tip at half
+            (#line, fullPos, CGPoint(x: 0.0, y: -100.0), .full),
+            (#line, fullPos, CGPoint(x: 0.0, y: 0.0), .full),
+            (#line, fullPos, CGPoint(x: 0.0, y: 500.0), .half), // project to half
+            (#line, fullPos, CGPoint(x: 0.0, y: 1000.0), .half), // block projecting to tip at half
+            (#line, fullPos, CGPoint(x: 0.0, y: 3000.0), .half), // block projecting to tip at half
+            (#line, fullPos + 10.0, CGPoint(x: 0.0, y: 100.0), .full), // redirect
+            (#line, halfPos - 10.0, CGPoint(x: 0.0, y: -100.0), .half), // redirect
+            (#line, halfPos, CGPoint(x: 0.0, y: -1000.0), .full), //project to full
+            (#line, halfPos, CGPoint(x: 0.0, y: -100.0), .half),
+            (#line, halfPos, CGPoint(x: 0.0, y: 0.0), .half),
+            (#line, halfPos, CGPoint(x: 0.0, y: 100.0), .half),
+            (#line, halfPos, CGPoint(x: 0.0, y: 1000.0), .tip), // project to tip
+            (#line, halfPos + 10.0, CGPoint(x: 0.0, y: 100.0), .half), // redirect
+            (#line, tipPos - 10.0, CGPoint(x: 0.0, y: -100.0), .tip), // redirect
+            (#line, tipPos, CGPoint(x: 0.0, y: -3000.0), .half), // block projecting to full at half
+            (#line, tipPos, CGPoint(x: 0.0, y: -1000.0), .half), // block projecting to full at half
+            (#line, tipPos, CGPoint(x: 0.0, y: -500.0), .half), // project to half
+            (#line, tipPos, CGPoint(x: 0.0, y: -100.0), .tip),
+            (#line, tipPos, CGPoint(x: 0.0, y: 0.0), .tip),
+            (#line, tipPos, CGPoint(x: 0.0, y: 100.0), .tip),
+            (#line, tipPos + 10.0, CGPoint(x: 0.0, y: -3000.0), .half), // block projecting to full at half
+            (#line, tipPos + 500.0, CGPoint(x: 0.0, y: -100.0), .tip), // far from bottomMostState
+            (#line, tipPos + 500.0, CGPoint(x: 0.0, y: 0.0), .tip), // far from bottomMostState
+            (#line, tipPos + 500.0, CGPoint(x: 0.0, y: 100.0), .tip), // far from bottomMostState
+        ])
+    }
+
+    func test_targetPosition_3positionsFromFull_bottomEdge() {
+        let delegate = FloatingPanelTestDelegate()
+        let fpc = FloatingPanelController(delegate: delegate)
+        fpc.layout = FloatingPanelLayout3PositionsBottomEdge()
+
+        fpc.showForTest()
+
+        let fullPos = fpc.surfaceLocation(for: .full).y
+        let halfPos = fpc.surfaceLocation(for: .half).y
+        let tipPos = fpc.surfaceLocation(for: .tip).y
+        // From .full
+        fpc.move(to: .full, animated: false)
+        assertTargetPosition(fpc.floatingPanel, with: [
+            (#line, tipPos - 500.0, CGPoint(x: 0.0, y: -100.0), .tip), // far from topMostState
+            (#line, tipPos - 500.0, CGPoint(x: 0.0, y: 0.0), .tip), // far from topMostState
+            (#line, tipPos - 500.0, CGPoint(x: 0.0, y: 100.0), .tip), // far from topMostState
+            (#line, tipPos - 10.0, CGPoint(x: 0.0, y: 3000.0), .half), // block projecting to full at half
+            (#line, tipPos, CGPoint(x: 0.0, y: -100.0), .tip),
+            (#line, tipPos, CGPoint(x: 0.0, y: 0.0), .tip),
+            (#line, tipPos, CGPoint(x: 0.0, y: 500.0), .half), // project to half
+            (#line, tipPos, CGPoint(x: 0.0, y: 1000.0), .half), // block projecting to full at half
+            (#line, tipPos, CGPoint(x: 0.0, y: 3000.0), .half), // block projecting to full at half
+            (#line, tipPos + 10.0, CGPoint(x: 0.0, y: 100.0), .tip), // redirect
+            (#line, halfPos - 10.0, CGPoint(x: 0.0, y: -100.0), .half), // redirect
+            (#line, halfPos, CGPoint(x: 0.0, y: -1000.0), .tip), //project to tip
+            (#line, halfPos, CGPoint(x: 0.0, y: -100.0), .half),
+            (#line, halfPos, CGPoint(x: 0.0, y: 0.0), .half),
+            (#line, halfPos, CGPoint(x: 0.0, y: 100.0), .half),
+            (#line, halfPos, CGPoint(x: 0.0, y: 1000.0), .full), // project to full
+            (#line, halfPos + 10.0, CGPoint(x: 0.0, y: 100.0), .half), // redirect
+            (#line, fullPos - 10.0, CGPoint(x: 0.0, y: -100.0), .full), // redirect
+            (#line, fullPos, CGPoint(x: 0.0, y: -3000.0), .half), // block projecting to tip at half
+            (#line, fullPos, CGPoint(x: 0.0, y: -1000.0), .half), // block projecting to tip at half
+            (#line, fullPos, CGPoint(x: 0.0, y: -500.0), .half), // project to half
+            (#line, fullPos, CGPoint(x: 0.0, y: -100.0), .full),
+            (#line, fullPos, CGPoint(x: 0.0, y: 0.0), .full),
+            (#line, fullPos, CGPoint(x: 0.0, y: 100.0), .full),
+            (#line, fullPos + 10.0, CGPoint(x: 0.0, y: -3000.0), .half), // block projecting to tip at half
+            (#line, fullPos + 500.0, CGPoint(x: 0.0, y: -100.0), .full), // far from bottomMostState
+            (#line, fullPos + 500.0, CGPoint(x: 0.0, y: 0.0), .full), // far from bottomMostState
+            (#line, fullPos + 500.0, CGPoint(x: 0.0, y: 100.0), .full), // far from bottomMostState
+        ])
+    }
+
+    func test_targetPosition_3positionsFromHalf() {
+        let delegate = FloatingPanelTestDelegate()
+        let fpc = FloatingPanelController(delegate: delegate)
+        fpc.layout = FloatingPanelLayout3Positions()
+
+        fpc.showForTest()
+
+        let fullPos = fpc.surfaceLocation(for: .full).y
+        let halfPos = fpc.surfaceLocation(for: .half).y
+        let tipPos = fpc.surfaceLocation(for: .tip).y
+        // From .half
+        fpc.move(to: .half, animated: false)
+        assertTargetPosition(fpc.floatingPanel, with: [
+            (#line, fullPos - 500.0, CGPoint(x: 0.0, y: -100.0), .full), // far from topMostState
+            (#line, fullPos - 500.0, CGPoint(x: 0.0, y: 0.0), .full), // far from topMostState
+            (#line, fullPos - 500.0, CGPoint(x: 0.0, y: 100.0), .full), // far from topMostState
+            (#line, fullPos, CGPoint(x: 0.0, y: -100.0), .full),
+            (#line, fullPos, CGPoint(x: 0.0, y: 0.0), .full),
+            (#line, fullPos, CGPoint(x: 0.0, y: 500.0), .half), // project to half
+            (#line, fullPos, CGPoint(x: 0.0, y: 1000.0), .half), // block projecting to tip at half
+            (#line, fullPos, CGPoint(x: 0.0, y: 3000.0), .half), // block projecting to tip at half
+            (#line, fullPos + 10.0, CGPoint(x: 0.0, y: 100.0), .full), // redirect
+            (#line, halfPos - 10.0, CGPoint(x: 0.0, y: -100.0), .half), // redirect
+            (#line, halfPos, CGPoint(x: 0.0, y: -1000.0), .full),// project to full
+            (#line, halfPos, CGPoint(x: 0.0, y: -100.0), .half),
+            (#line, halfPos, CGPoint(x: 0.0, y: 0.0), .half),
+            (#line, halfPos, CGPoint(x: 0.0, y: 100.0), .half),
+            (#line, halfPos, CGPoint(x: 0.0, y: 1000.0), .tip), // project to tip
+            (#line, halfPos + 10.0, CGPoint(x: 0.0, y: 100.0), .half), // redirect
+            (#line, tipPos - 10.0, CGPoint(x: 0.0, y: -100.0), .tip), // redirect
+            (#line, tipPos, CGPoint(x: 0.0, y: -3000.0), .half), // block projecting to full at half
+            (#line, tipPos, CGPoint(x: 0.0, y: -1000.0), .half), // block projecting to full at half
+            (#line, tipPos, CGPoint(x: 0.0, y: -500.0), .half), // project to half
+            (#line, tipPos, CGPoint(x: 0.0, y: -100.0), .tip),
+            (#line, tipPos, CGPoint(x: 0.0, y: 0.0), .tip),
+            (#line, tipPos, CGPoint(x: 0.0, y: 100.0), .tip),
+            (#line, tipPos + 500.0, CGPoint(x: 0.0, y: -100.0), .tip), // far from bottomMostState
+            (#line, tipPos + 500.0, CGPoint(x: 0.0, y: 0.0), .tip), // far from bottomMostState
+            (#line, tipPos + 500.0, CGPoint(x: 0.0, y: 100.0), .tip), // far from bottomMostState
+        ])
+    }
+
+    func test_targetPosition_3positionsFromHalf_bottomEdge() {
+        let delegate = FloatingPanelTestDelegate()
+        let fpc = FloatingPanelController(delegate: delegate)
+        fpc.layout = FloatingPanelLayout3PositionsBottomEdge()
+
+            fpc.showForTest()
+
+            let fullPos = fpc.surfaceLocation(for: .full).y
+            let halfPos = fpc.surfaceLocation(for: .half).y
+            let tipPos = fpc.surfaceLocation(for: .tip).y
+            // From .half
+            fpc.move(to: .half, animated: false)
+            assertTargetPosition(fpc.floatingPanel, with: [
+                (#line, tipPos - 500.0, CGPoint(x: 0.0, y: -100.0), .tip), // far from topMostState
+                (#line, tipPos - 500.0, CGPoint(x: 0.0, y: 0.0), .tip), // far from topMostState
+                (#line, tipPos - 500.0, CGPoint(x: 0.0, y: 100.0), .tip), // far from topMostState
+                (#line, tipPos, CGPoint(x: 0.0, y: -100.0), .tip),
+                (#line, tipPos, CGPoint(x: 0.0, y: 0.0), .tip),
+                (#line, tipPos, CGPoint(x: 0.0, y: 500.0), .half), // project to half
+                (#line, tipPos, CGPoint(x: 0.0, y: 1000.0), .half), // block projecting to full at half
+                (#line, tipPos, CGPoint(x: 0.0, y: 3000.0), .half), // block projecting to full at half
+                (#line, tipPos + 10.0, CGPoint(x: 0.0, y: 100.0), .tip), // redirect
+                (#line, halfPos - 10.0, CGPoint(x: 0.0, y: -100.0), .half), // redirect
+                (#line, halfPos, CGPoint(x: 0.0, y: -1000.0), .tip),// project to tip
+                (#line, halfPos, CGPoint(x: 0.0, y: -100.0), .half),
+                (#line, halfPos, CGPoint(x: 0.0, y: 0.0), .half),
+                (#line, halfPos, CGPoint(x: 0.0, y: 100.0), .half),
+                (#line, halfPos, CGPoint(x: 0.0, y: 1000.0), .full), // project to full
+                (#line, halfPos + 10.0, CGPoint(x: 0.0, y: 100.0), .half), // redirect
+                (#line, fullPos - 10.0, CGPoint(x: 0.0, y: -100.0), .full), // redirect
+                (#line, fullPos, CGPoint(x: 0.0, y: -3000.0), .half), // block projecting to tip at half
+                (#line, fullPos, CGPoint(x: 0.0, y: -1000.0), .half), // block projecting to tip at half
+                (#line, fullPos, CGPoint(x: 0.0, y: -500.0), .half), // project to half
+                (#line, fullPos, CGPoint(x: 0.0, y: -100.0), .full),
+                (#line, fullPos, CGPoint(x: 0.0, y: 0.0), .full),
+                (#line, fullPos, CGPoint(x: 0.0, y: 100.0), .full),
+                (#line, fullPos + 500.0, CGPoint(x: 0.0, y: -100.0), .full), // far from bottomMostState
+                (#line, fullPos + 500.0, CGPoint(x: 0.0, y: 0.0), .full), // far from bottomMostState
+                (#line, fullPos + 500.0, CGPoint(x: 0.0, y: 100.0), .full), // far from bottomMostState
+            ])
+    }
+
+    func test_targetPosition_3positionsFromTip() {
+        let delegate = FloatingPanelTestDelegate()
+        let fpc = FloatingPanelController(delegate: delegate)
+        fpc.layout = FloatingPanelLayout3Positions()
+
+        fpc.showForTest()
+
+        let fullPos = fpc.surfaceLocation(for: .full).y
+        let halfPos = fpc.surfaceLocation(for: .half).y
+        let tipPos = fpc.surfaceLocation(for: .tip).y
+
+        // From .tip
+        fpc.move(to: .tip, animated: false)
+        assertTargetPosition(fpc.floatingPanel, with: [
+            (#line, fullPos - 500.0, CGPoint(x: 0.0, y: -100.0), .full), // far from topMostState
+            (#line, fullPos - 500.0, CGPoint(x: 0.0, y: 0.0), .full), // far from topMostState
+            (#line, fullPos - 500.0, CGPoint(x: 0.0, y: 100.0), .full), // far from topMostState
+            (#line, fullPos, CGPoint(x: 0.0, y: -100.0), .full),
+            (#line, fullPos, CGPoint(x: 0.0, y: 0.0), .full),
+            (#line, fullPos, CGPoint(x: 0.0, y: 500.0), .half), // project to half
+            (#line, fullPos, CGPoint(x: 0.0, y: 1000.0), .half), // block projecting to tip at half
+            (#line, fullPos, CGPoint(x: 0.0, y: 3000.0), .half), // block projecting to tip at half
+            (#line, fullPos + 10.0, CGPoint(x: 0.0, y: 100.0), .full), // redirect
+            (#line, halfPos - 10.0, CGPoint(x: 0.0, y: -100.0), .half), // redirect
+            (#line, halfPos, CGPoint(x: 0.0, y: -3000.0), .full), // project to full
+            (#line, halfPos, CGPoint(x: 0.0, y: -100.0), .half),
+            (#line, halfPos, CGPoint(x: 0.0, y: 0.0), .half),
+            (#line, halfPos, CGPoint(x: 0.0, y: 100.0), .half),
+            (#line, halfPos, CGPoint(x: 0.0, y: 1000.0), .tip), // project to tip
+            (#line, halfPos + 10.0, CGPoint(x: 0.0, y: 100.0), .half), // redirect
+            (#line, tipPos - 10.0, CGPoint(x: 0.0, y: -100.0), .tip), // redirect
+            (#line, tipPos, CGPoint(x: 0.0, y: -3000.0), .half), // block projecting to full at half
+            (#line, tipPos, CGPoint(x: 0.0, y: -1000.0), .half), // block projecting to full at half
+            (#line, tipPos, CGPoint(x: 0.0, y: -500.0), .half), // project to half
+            (#line, tipPos, CGPoint(x: 0.0, y: -100.0), .tip),
+            (#line, tipPos, CGPoint(x: 0.0, y: 0.0), .tip),
+            (#line, tipPos, CGPoint(x: 0.0, y: 100.0), .tip),
+            (#line, tipPos + 500.0, CGPoint(x: 0.0, y: -100.0), .tip), // far from bottomMostState
+            (#line, tipPos + 500.0, CGPoint(x: 0.0, y: 0.0), .tip), // far from bottomMostState
+            (#line, tipPos + 500.0, CGPoint(x: 0.0, y: 100.0), .tip), // far from bottomMostState
+        ])
+    }
+
+    func test_targetPosition_3positionsFromTip_bottomEdge() {
+        let delegate = FloatingPanelTestDelegate()
+        let fpc = FloatingPanelController(delegate: delegate)
+        fpc.layout = FloatingPanelLayout3PositionsBottomEdge()
+
+        fpc.showForTest()
+
+            let fullPos = fpc.surfaceLocation(for: .full).y
+            let halfPos = fpc.surfaceLocation(for: .half).y
+            let tipPos = fpc.surfaceLocation(for: .tip).y
+
+            // From .tip
+            fpc.move(to: .tip, animated: false)
+            assertTargetPosition(fpc.floatingPanel, with: [
+                (#line, tipPos - 500.0, CGPoint(x: 0.0, y: -100.0), .tip), // far from topMostState
+                (#line, tipPos - 500.0, CGPoint(x: 0.0, y: 0.0), .tip), // far from topMostState
+                (#line, tipPos - 500.0, CGPoint(x: 0.0, y: 100.0), .tip), // far from topMostState
+                (#line, tipPos, CGPoint(x: 0.0, y: -100.0), .tip),
+                (#line, tipPos, CGPoint(x: 0.0, y: 0.0), .tip),
+                (#line, tipPos, CGPoint(x: 0.0, y: 500.0), .half), // project to half
+                (#line, tipPos, CGPoint(x: 0.0, y: 1000.0), .half), // block projecting to tip at half
+                (#line, tipPos, CGPoint(x: 0.0, y: 3000.0), .half), // block projecting to tip at half
+                (#line, tipPos + 10.0, CGPoint(x: 0.0, y: 100.0), .tip), // redirect
+                (#line, halfPos - 10.0, CGPoint(x: 0.0, y: -100.0), .half), // redirect
+                (#line, halfPos, CGPoint(x: 0.0, y: -3000.0), .tip), // project to full
+                (#line, halfPos, CGPoint(x: 0.0, y: -100.0), .half),
+                (#line, halfPos, CGPoint(x: 0.0, y: 0.0), .half),
+                (#line, halfPos, CGPoint(x: 0.0, y: 100.0), .half),
+                (#line, halfPos, CGPoint(x: 0.0, y: 1000.0), .full), // project to tip
+                (#line, halfPos + 10.0, CGPoint(x: 0.0, y: 100.0), .half), // redirect
+                (#line, fullPos - 10.0, CGPoint(x: 0.0, y: -100.0), .full), // redirect
+                (#line, fullPos, CGPoint(x: 0.0, y: -3000.0), .half), // block projecting to full at half
+                (#line, fullPos, CGPoint(x: 0.0, y: -1000.0), .half), // block projecting to full at half
+                (#line, fullPos, CGPoint(x: 0.0, y: -500.0), .half), // project to half
+                (#line, fullPos, CGPoint(x: 0.0, y: -100.0), .full),
+                (#line, fullPos, CGPoint(x: 0.0, y: 0.0), .full),
+                (#line, fullPos, CGPoint(x: 0.0, y: 100.0), .full),
+                (#line, fullPos + 500.0, CGPoint(x: 0.0, y: -100.0), .full), // far from bottomMostState
+                (#line, fullPos + 500.0, CGPoint(x: 0.0, y: 0.0), .full), // far from bottomMostState
+                (#line, fullPos + 500.0, CGPoint(x: 0.0, y: 100.0), .full), // far from bottomMostState
+            ])
+    }
+
+    func test_targetPosition_3positionsAllProjection() {
+        let delegate = FloatingPanelTestDelegate()
+        let fpc = FloatingPanelController(delegate: delegate)
+        fpc.layout = FloatingPanelLayout3Positions()
+        fpc.behavior = FloatingPanelProjectableBehavior()
+
+        fpc.showForTest()
+
+        let fullPos = fpc.surfaceLocation(for: .full).y
+        let halfPos = fpc.surfaceLocation(for: .half).y
+        let tipPos = fpc.surfaceLocation(for: .tip).y
+
+        // From .full
+        fpc.move(to: .full, animated: false)
+        assertTargetPosition(fpc.floatingPanel, with: [
+            (#line, fullPos - 10.0, CGPoint(x: 0.0, y: 3000.0), .tip),
+            (#line, fullPos, CGPoint(x: 0.0, y: 1000.0), .tip),
+            (#line, fullPos, CGPoint(x: 0.0, y: 3000.0), .tip),
+            (#line, halfPos, CGPoint(x: 0.0, y: 1000.0), .tip),
+            (#line, halfPos, CGPoint(x: 0.0, y: -1000.0), .full),
+            (#line, tipPos, CGPoint(x: 0.0, y: -3000.0), .full),
+            (#line, tipPos, CGPoint(x: 0.0, y: -1000.0), .full),
+            (#line, tipPos + 10.0, CGPoint(x: 0.0, y: -3000.0), .full),
+            ])
+
+        // From .half
+        fpc.move(to: .tip, animated: false)
+        assertTargetPosition(fpc.floatingPanel, with: [
+            (#line, fullPos, CGPoint(x: 0.0, y: 1000.0), .tip),
+            (#line, fullPos, CGPoint(x: 0.0, y: 3000.0), .tip),
+            (#line, tipPos, CGPoint(x: 0.0, y: -3000.0), .full),
+            (#line, tipPos, CGPoint(x: 0.0, y: -1000.0), .full),
+            ])
+
+        // From .tip
+        fpc.move(to: .tip, animated: false)
+        assertTargetPosition(fpc.floatingPanel, with: [
+            (#line, fullPos - 10.0, CGPoint(x: 0.0, y: 3000.0), .tip),
+            (#line, fullPos, CGPoint(x: 0.0, y: 1000.0), .tip),
+            (#line, fullPos, CGPoint(x: 0.0, y: 3000.0), .tip),
+            (#line, halfPos, CGPoint(x: 0.0, y: 1000.0), .tip),
+            (#line, halfPos, CGPoint(x: 0.0, y: -1000.0), .full),
+            (#line, tipPos, CGPoint(x: 0.0, y: -3000.0), .full),
+            (#line, tipPos, CGPoint(x: 0.0, y: -1000.0), .full),
+            (#line, tipPos + 10.0, CGPoint(x: 0.0, y: -3000.0), .full),
+            ])
+    }
+
+    func test_targetPosition_3positionsWithHidden() {
+        class FloatingPanelLayout3PositionsWithHidden: FloatingPanelLayout {
+            let initialState: FloatingPanelState = .hidden
+            let position: FloatingPanelPosition = .bottom
+            var anchors: [FloatingPanelState : FloatingPanelLayoutAnchoring] {
+                return [
+                    .full: FloatingPanelLayoutAnchor(absoluteInset: 20.0, edge: .top, referenceGuide: .superview),
+                    .half: FloatingPanelLayoutAnchor(absoluteInset: 250.0, edge: .bottom, referenceGuide: .superview),
+                    .hidden: FloatingPanelLayoutAnchor(absoluteInset: 0, edge: .bottom, referenceGuide: .superview),
+                ]
+            }
+        }
+        let delegate = FloatingPanelTestDelegate()
+        let fpc = FloatingPanelController(delegate: delegate)
+        fpc.layout = FloatingPanelLayout3PositionsWithHidden()
+
+        fpc.showForTest()
+        XCTAssertEqual(fpc.state, .hidden)
+
+        fpc.move(to: .full, animated: false)
+        assertTargetPosition(fpc.floatingPanel, with: [
+            (#line, fpc.surfaceView.frame.minY, CGPoint(x: 0.0, y: 1000.0), .half),
+            ])
+        fpc.move(to: .half, animated: false)
+        assertTargetPosition(fpc.floatingPanel, with: [
+            (#line, fpc.surfaceView.frame.minY, CGPoint(x: 0.0, y: -100.0), .half),
+            (#line, fpc.surfaceView.frame.minY, CGPoint(x: 0.0, y: -1000.0), .full),
+            (#line, fpc.surfaceView.frame.minY, CGPoint(x: 0.0, y: 0.0), .half),
+            (#line, fpc.surfaceView.frame.minY, CGPoint(x: 0.0, y: 1000.0), .hidden),
+            ])
+    }
+
+    func test_targetPosition_3positionsWithHiddenWithoutFull() {
+        class FloatingPanelLayout3Positions: FloatingPanelLayout {
+            let initialState: FloatingPanelState = .hidden
+            let position: FloatingPanelPosition = .bottom
+            var anchors: [FloatingPanelState : FloatingPanelLayoutAnchoring] {
+                return [
+                    .half: FloatingPanelLayoutAnchor(absoluteInset: 250.0, edge: .bottom, referenceGuide: .superview),
+                    .tip: FloatingPanelLayoutAnchor(absoluteInset: 60.0, edge: .bottom, referenceGuide: .superview),
+                    .hidden: FloatingPanelLayoutAnchor(absoluteInset: 0, edge: .bottom, referenceGuide: .superview),
+                ]
+            }
+        }
+
+        let delegate = FloatingPanelTestDelegate()
+        let fpc = FloatingPanelController(delegate: delegate)
+        fpc.layout = FloatingPanelLayout3Positions()
+
+        fpc.showForTest()
+        fpc.behavior = FloatingPanelProjectableBehavior()
+        XCTAssertEqual(fpc.state, .hidden)
+
+        let halfPos = fpc.surfaceLocation(for: .half).y
+        let tipPos = fpc.surfaceLocation(for: .tip).y
+        //let hiddenPos = fpc.surfaceLocation(for: .hidden)
+
+        fpc.move(to: .half, animated: false)
+        assertTargetPosition(fpc.floatingPanel, with: [
+            (#line, halfPos, CGPoint(x: 0.0, y: -100.0), .half),
+            (#line, halfPos, CGPoint(x: 0.0, y: 0.0), .half),
+            (#line, halfPos, CGPoint(x: 0.0, y: 385.0), .tip), // projection
+            (#line, halfPos, CGPoint(x: 0.0, y: 1000.0), .hidden), // projection
+            (#line, halfPos + 10.0, CGPoint(x: 0.0, y: 100.0), .half), // redirection
+            (#line, tipPos - 10.0, CGPoint(x: 0.0, y: -100.0), .tip), // redirection
+            (#line, tipPos, CGPoint(x: 0.0, y: -3000.0), .half), //projection
+            (#line, tipPos, CGPoint(x: 0.0, y: -10.0), .tip),
+            (#line, tipPos, CGPoint(x: 0.0, y: 0.0), .tip),
+            (#line, tipPos, CGPoint(x: 0.0, y: 10.0), .tip),
+            (#line, tipPos, CGPoint(x: 0.0, y: 1000.0), .hidden), //projection
+            (#line, tipPos + 10.0, CGPoint(x: 0.0, y: 10.0), .tip), // redirection
+            (#line, tipPos - 10.0, CGPoint(x: 0.0, y: 10.0), .tip), // redirection
+            ])
+        fpc.move(to: .tip, animated: false)
+        assertTargetPosition(fpc.floatingPanel, with: [
+            (#line, tipPos, CGPoint(x: 0.0, y: -100.0), .tip),
+            (#line, tipPos, CGPoint(x: 0.0, y: -1000.0), .half),
+            (#line, tipPos, CGPoint(x: 0.0, y: 0.0), .tip),
+            (#line, tipPos, CGPoint(x: 0.0, y: 1000.0), .hidden),
+            ])
+    }
+}
+
+private class FloatingPanelLayout3Positions: FloatingPanelTestLayout {
+    override var initialState: FloatingPanelState {
+        return .tip
+    }
+}
+
+private class FloatingPanelLayout3PositionsBottomEdge: FloatingPanelTop2BottomTestLayout {
+    override var initialState: FloatingPanelState {
+        return .tip
+    }
+}
+
+private typealias TestParameter = (UInt, CGFloat,  CGPoint, FloatingPanelState)
+private func assertTargetPosition(_ floatingPanel: Core, with params: [TestParameter]) {
+    params.forEach { (line, pos, velocity, result) in
+        floatingPanel.surfaceView.frame.origin.y = pos
+        XCTAssertEqual(floatingPanel.targetPosition(from: pos, with: velocity.y), result, line: line)
+    }
+}

Tests/LayoutTests.swift

@@ -0,0 +1,662 @@
+// Copyright 2018 the FloatingPanel authors. All rights reserved. MIT license.
+
+import XCTest
+@testable import FloatingPanel
+
+class LayoutTests: XCTestCase {
+    var fpc: FloatingPanelController!
+    override func setUp() {
+        fpc = FloatingPanelController(delegate: nil)
+        fpc.loadViewIfNeeded()
+        fpc.view.frame = CGRect(x: 0, y: 0, width: 375, height: 667)
+    }
+    override func tearDown() {}
+
+    func test_layoutAdapter_topAndBottomMostState() {
+        XCTAssertEqual(fpc.floatingPanel.layoutAdapter.edgeMostState, .full)
+        XCTAssertEqual(fpc.floatingPanel.layoutAdapter.edgeLeastState, .tip)
+
+        class FloatingPanelLayoutWithHidden: FloatingPanelLayout {
+            var anchors: [FloatingPanelState: FloatingPanelLayoutAnchoring]  {
+                return [
+                    .full: FloatingPanelLayoutAnchor(absoluteInset: 18.0, edge: .top, referenceGuide: .safeArea),
+                    .half: FloatingPanelLayoutAnchor(fractionalInset: 0.5, edge: .bottom, referenceGuide: .safeArea),
+                    .hidden: FloatingPanelLayoutAnchor(absoluteInset: 0, edge: .bottom, referenceGuide: .superview)
+                ]
+            }
+            let initialState: FloatingPanelState = .hidden
+            let position: FloatingPanelPosition = .bottom
+        }
+        class FloatingPanelLayout2Positions: FloatingPanelLayout {
+            var anchors: [FloatingPanelState: FloatingPanelLayoutAnchoring]  {
+                return [
+                    .half: FloatingPanelLayoutAnchor(fractionalInset: 0.5, edge: .bottom, referenceGuide: .safeArea),
+                    .tip: FloatingPanelLayoutAnchor(absoluteInset: 69.0, edge: .bottom, referenceGuide: .safeArea),
+                ]
+            }
+            let initialState: FloatingPanelState = .tip
+            let position: FloatingPanelPosition = .bottom
+        }
+        fpc.layout = FloatingPanelLayoutWithHidden()
+        XCTAssertEqual(fpc.floatingPanel.layoutAdapter.edgeMostState, .full)
+        XCTAssertEqual(fpc.floatingPanel.layoutAdapter.edgeLeastState, .hidden)
+
+        fpc.layout = FloatingPanelLayout2Positions()
+        XCTAssertEqual(fpc.floatingPanel.layoutAdapter.edgeMostState, .half)
+        XCTAssertEqual(fpc.floatingPanel.layoutAdapter.edgeLeastState, .tip)
+    }
+
+    func test_layoutSegment_3position() {
+        class FloatingPanelLayout3Positions: FloatingPanelTestLayout {
+            override var initialState: FloatingPanelState  { .half }
+        }
+
+        fpc.layout = FloatingPanelLayout3Positions()
+
+        let fullPos = fpc.surfaceLocation(for: .full).y
+        let halfPos = fpc.surfaceLocation(for: .half).y
+        let tipPos = fpc.surfaceLocation(for: .tip).y
+
+        let minPos = CGFloat.leastNormalMagnitude
+        let maxPos = CGFloat.greatestFiniteMagnitude
+
+        assertLayoutSegment(fpc.floatingPanel, with: [
+            (#line, pos: minPos, forwardY: true, lower: nil, upper: .full),
+            (#line, pos: minPos, forwardY: false, lower: nil, upper: .full),
+            (#line, pos: fullPos, forwardY: true, lower: .full, upper: .half),
+            (#line, pos: fullPos, forwardY: false, lower: nil,  upper: .full),
+            (#line, pos: halfPos, forwardY: true, lower: .half, upper: .tip),
+            (#line, pos: halfPos, forwardY: false, lower: .full,  upper: .half),
+            (#line, pos: tipPos, forwardY: true, lower: .tip, upper: nil),
+            (#line, pos: tipPos, forwardY: false, lower: .half,  upper: .tip),
+            (#line, pos: maxPos, forwardY: true, lower: .tip, upper: nil),
+            (#line, pos: maxPos, forwardY: false, lower: .tip, upper: nil),
+            ])
+    }
+
+    func test_layoutSegment_2positions() {
+        class FloatingPanelLayout2Positions: FloatingPanelTestLayout {
+            override var initialState: FloatingPanelState  { .half }
+            override var anchors: [FloatingPanelState : FloatingPanelLayoutAnchoring]
+                { super.anchors.filter { (key, _) in key != .tip } }
+        }
+
+        fpc.layout = FloatingPanelLayout2Positions()
+
+        let fullPos = fpc.surfaceLocation(for: .full).y
+        let halfPos = fpc.surfaceLocation(for: .half).y
+
+        let minPos = CGFloat.leastNormalMagnitude
+        let maxPos = CGFloat.greatestFiniteMagnitude
+
+        assertLayoutSegment(fpc.floatingPanel, with: [
+            (#line, pos: minPos, forwardY: true, lower: nil, upper: .full),
+            (#line, pos: minPos, forwardY: false, lower: nil, upper: .full),
+            (#line, pos: fullPos, forwardY: true, lower: .full, upper: .half),
+            (#line, pos: fullPos, forwardY: false, lower: nil,  upper: .full),
+            (#line, pos: halfPos, forwardY: true, lower: .half, upper: nil),
+            (#line, pos: halfPos, forwardY: false, lower: .full,  upper: .half),
+            (#line, pos: maxPos, forwardY: true, lower: .half, upper: nil),
+            (#line, pos: maxPos, forwardY: false, lower: .half, upper: nil),
+            ])
+    }
+
+    func test_layoutSegment_1positions() {
+        class FloatingPanelLayout1Positions: FloatingPanelTestLayout {
+            override var initialState: FloatingPanelState  { .full }
+            override var anchors: [FloatingPanelState : FloatingPanelLayoutAnchoring]
+                { super.anchors.filter { (key, _) in key == .full } }
+        }
+
+        fpc.layout = FloatingPanelLayout1Positions()
+
+        let fullPos = fpc.surfaceLocation(for: .full).y
+
+        let minPos = CGFloat.leastNormalMagnitude
+        let maxPos = CGFloat.greatestFiniteMagnitude
+
+        assertLayoutSegment(fpc.floatingPanel, with: [
+            (#line, pos: minPos, forwardY: true, lower: nil, upper: .full),
+            (#line, pos: minPos, forwardY: false, lower: nil, upper: .full),
+            (#line, pos: fullPos, forwardY: true, lower: .full, upper: nil),
+            (#line, pos: fullPos, forwardY: false, lower: nil,  upper: .full),
+            (#line, pos: maxPos, forwardY: true, lower: .full, upper: nil),
+            (#line, pos: maxPos, forwardY: false, lower: .full, upper: nil),
+            ])
+    }
+
+    func test_updateInteractiveEdgeConstraint() {
+        fpc.showForTest()
+        fpc.move(to: .full, animated: false)
+
+        fpc.floatingPanel.layoutAdapter.startInteraction(at: fpc.state)
+        fpc.floatingPanel.layoutAdapter.startInteraction(at: fpc.state) // Should be ignore
+
+        let fullPos = fpc.surfaceLocation(for: .full).y
+        let tipPos = fpc.surfaceLocation(for: .tip).y
+
+        var next: CGFloat
+
+        fpc.floatingPanel.layoutAdapter.updateInteractiveEdgeConstraint(diff: -100.0,
+                                                                        overflow: false,
+                                                                        allowsRubberBanding: fpc.floatingPanel.behaviorAdapter.allowsRubberBanding(for:))
+        next = fpc.surfaceLocation.y
+        XCTAssertEqual(next, fullPos)
+
+        fpc.floatingPanel.layoutAdapter.updateInteractiveEdgeConstraint(diff: 100.0,
+                                                                        overflow: true,
+                                                                        allowsRubberBanding: fpc.floatingPanel.behaviorAdapter.allowsRubberBanding(for:))
+        next = fpc.surfaceLocation.y
+        XCTAssertEqual(next, fullPos + 100.0)
+
+        fpc.floatingPanel.layoutAdapter.updateInteractiveEdgeConstraint(diff: tipPos - fullPos,
+                                                                        overflow: true,
+                                                                        allowsRubberBanding: fpc.floatingPanel.behaviorAdapter.allowsRubberBanding(for:))
+        next = fpc.surfaceLocation.y
+        XCTAssertEqual(next, tipPos)
+
+        fpc.floatingPanel.layoutAdapter.updateInteractiveEdgeConstraint(diff: tipPos - fullPos + 100.0,
+                                                                        overflow: false,
+                                                                        allowsRubberBanding: fpc.floatingPanel.behaviorAdapter.allowsRubberBanding(for:))
+        next = fpc.surfaceLocation.y
+        XCTAssertEqual(next, tipPos)
+
+        fpc.floatingPanel.layoutAdapter.updateInteractiveEdgeConstraint(diff: tipPos - fullPos + 100.0,
+                                                                        overflow: true,
+                                                                        allowsRubberBanding: fpc.floatingPanel.behaviorAdapter.allowsRubberBanding(for:))
+        next = fpc.surfaceLocation.y
+        XCTAssertEqual(next, tipPos + 100.0)
+
+        fpc.floatingPanel.layoutAdapter.endInteraction(at: fpc.state)
+    }
+
+    func test_updateInteractiveEdgeConstraint_bottomEdge() {
+        fpc.layout = FloatingPanelTop2BottomTestLayout()
+        fpc.showForTest()
+        fpc.move(to: .tip, animated: false)
+        XCTAssertEqual(fpc.surfaceView.frame, CGRect(x: 0.0, y: -667.0 + 60.0, width: 375.0, height: 667))
+        XCTAssertEqual(fpc.surfaceView.containerView.frame, CGRect(x: 0.0, y: -667.0,
+                                                                   width: 375.0, height: 667 * 2.0))
+
+        fpc.floatingPanel.layoutAdapter.startInteraction(at: fpc.state)
+        fpc.floatingPanel.layoutAdapter.startInteraction(at: fpc.state) // Should be ignore
+
+        XCTAssertEqual(fpc.floatingPanel.layoutAdapter.interactionConstraint?.constant, 60.0)
+
+        let fullPos = fpc.surfaceLocation(for: .full).y
+        let tipPos = fpc.surfaceLocation(for: .tip).y
+
+        var pre: CGFloat
+        var next: CGFloat
+        pre = fpc.surfaceLocation.y
+        fpc.floatingPanel.layoutAdapter.updateInteractiveEdgeConstraint(diff: -100.0,
+                                                                        overflow: false,
+                                                                        allowsRubberBanding: fpc.floatingPanel.behaviorAdapter.allowsRubberBanding(for:))
+        next = fpc.surfaceLocation.y
+        XCTAssertEqual(next, pre)
+
+        fpc.floatingPanel.layoutAdapter.updateInteractiveEdgeConstraint(diff: 100.0,
+                                                                        overflow: true,
+                                                                        allowsRubberBanding: fpc.floatingPanel.behaviorAdapter.allowsRubberBanding(for:))
+        next = fpc.surfaceLocation.y
+        XCTAssertEqual(next, tipPos + 100.0)
+
+        fpc.floatingPanel.layoutAdapter.updateInteractiveEdgeConstraint(diff: fullPos - tipPos,
+                                                                        overflow: true,
+                                                                        allowsRubberBanding: fpc.floatingPanel.behaviorAdapter.allowsRubberBanding(for:))
+        next = fpc.surfaceLocation.y
+        XCTAssertEqual(next, fullPos)
+
+        fpc.floatingPanel.layoutAdapter.updateInteractiveEdgeConstraint(diff: fullPos - tipPos + 100,
+                                                                        overflow: false,
+                                                                        allowsRubberBanding: fpc.floatingPanel.behaviorAdapter.allowsRubberBanding(for:))
+        next = fpc.surfaceLocation.y
+        XCTAssertEqual(next, fullPos)
+
+        fpc.floatingPanel.layoutAdapter.updateInteractiveEdgeConstraint(diff: fullPos - tipPos + 100,
+                                                                        overflow: true,
+                                                                        allowsRubberBanding: fpc.floatingPanel.behaviorAdapter.allowsRubberBanding(for:))
+        next = fpc.surfaceLocation.y
+        XCTAssertEqual(next, fullPos + 100.0)
+
+        fpc.floatingPanel.layoutAdapter.endInteraction(at: fpc.state)
+    }
+
+    func test_updateInteractiveEdgeConstraintWithHidden() {
+        class FloatingPanelLayout2Positions: FloatingPanelLayout {
+            var anchors: [FloatingPanelState: FloatingPanelLayoutAnchoring]  {
+                return [
+                    .full: FloatingPanelLayoutAnchor(absoluteInset: 18.0, edge: .bottom, referenceGuide: .safeArea),
+                    .hidden: FloatingPanelLayoutAnchor(absoluteInset: 0, edge: .bottom, referenceGuide: .superview),
+                ]
+            }
+            let initialState: FloatingPanelState = .hidden
+            let position: FloatingPanelPosition = .bottom
+        }
+        fpc.layout = FloatingPanelLayout2Positions()
+        fpc.showForTest()
+        fpc.move(to: .full, animated: false)
+
+        fpc.floatingPanel.layoutAdapter.startInteraction(at: fpc.state)
+
+        let fullPos = fpc.surfaceLocation(for: .full).y
+        let hiddenPos = fpc.surfaceLocation(for: .hidden).y
+
+        var next: CGFloat
+
+        fpc.floatingPanel.layoutAdapter.updateInteractiveEdgeConstraint(diff: -100.0,
+                                                                        overflow: false,
+                                                                        allowsRubberBanding: fpc.floatingPanel.behaviorAdapter.allowsRubberBanding(for:))
+        next = fpc.surfaceLocation.y
+        XCTAssertEqual(next, fullPos)
+
+        fpc.floatingPanel.layoutAdapter.updateInteractiveEdgeConstraint(diff: -100.0,
+                                                                        overflow: true,
+                                                                        allowsRubberBanding: fpc.floatingPanel.behaviorAdapter.allowsRubberBanding(for:))
+        next = fpc.surfaceLocation.y
+        XCTAssertEqual(next, fullPos - 100.0)
+
+        fpc.floatingPanel.layoutAdapter.updateInteractiveEdgeConstraint(diff: hiddenPos - fullPos + 100.0,
+                                                                        overflow: true,
+                                                                        allowsRubberBanding: fpc.floatingPanel.behaviorAdapter.allowsRubberBanding(for:))
+        next = fpc.surfaceLocation.y
+        XCTAssertEqual(next, hiddenPos + 100.0)
+
+        fpc.floatingPanel.layoutAdapter.endInteraction(at: fpc.state)
+    }
+
+    func test_updateInteractiveEdgeConstraintWithHidden_bottomEdge() {
+        class FloatingPanelLayout2Positions: FloatingPanelLayout {
+            var anchors: [FloatingPanelState: FloatingPanelLayoutAnchoring]  {
+                [
+                    .full: FloatingPanelLayoutAnchor(absoluteInset: 18.0, edge: .bottom, referenceGuide: .safeArea),
+                    .hidden: FloatingPanelLayoutAnchor(absoluteInset: 0, edge: .top, referenceGuide: .superview),
+                ]
+            }
+            let initialState: FloatingPanelState = .hidden
+            let position: FloatingPanelPosition = .top
+        }
+        fpc.layout = FloatingPanelLayout2Positions()
+        fpc.showForTest()
+        fpc.move(to: .full, animated: false)
+
+        fpc.floatingPanel.layoutAdapter.startInteraction(at: fpc.state)
+
+        let fullPos = fpc.surfaceLocation(for: .full).y
+        let hiddenPos = fpc.surfaceLocation(for: .hidden).y
+
+        var next: CGFloat
+
+        fpc.floatingPanel.layoutAdapter.updateInteractiveEdgeConstraint(diff: 100.0,
+                                                                        overflow: false,
+                                                                        allowsRubberBanding: fpc.floatingPanel.behaviorAdapter.allowsRubberBanding(for:))
+        next = fpc.surfaceLocation.y
+        XCTAssertEqual(next, fullPos)
+
+        fpc.floatingPanel.layoutAdapter.updateInteractiveEdgeConstraint(diff: 100.0,
+                                                                        overflow: true,
+                                                                        allowsRubberBanding: fpc.floatingPanel.behaviorAdapter.allowsRubberBanding(for:))
+        next = fpc.surfaceLocation.y
+        XCTAssertEqual(next, fullPos + 100.0)
+
+        fpc.floatingPanel.layoutAdapter.updateInteractiveEdgeConstraint(diff: hiddenPos - fullPos + 100.0,
+                                                                        overflow: true,
+                                                                        allowsRubberBanding: fpc.floatingPanel.behaviorAdapter.allowsRubberBanding(for:))
+        next = fpc.surfaceLocation.y
+        XCTAssertEqual(next, hiddenPos + 100.0)
+
+        fpc.floatingPanel.layoutAdapter.endInteraction(at: fpc.state)
+    }
+
+    func test_updateInteractiveTopConstraintWithMinusInsets() {
+        class FloatingPanelLayoutMinusInsets: FloatingPanelLayout {
+            var anchors: [FloatingPanelState: FloatingPanelLayoutAnchoring]  {
+                [
+                    .full: FloatingPanelLayoutAnchor(absoluteInset: -200, edge: .top, referenceGuide: .safeArea),
+                    .tip: FloatingPanelLayoutAnchor(absoluteInset: -200, edge: .bottom, referenceGuide: .safeArea),
+                ]
+            }
+            let initialState: FloatingPanelState = .full
+            let position: FloatingPanelPosition = .bottom
+        }
+        fpc.layout = FloatingPanelLayoutMinusInsets()
+        fpc.showForTest()
+        fpc.floatingPanel.layoutAdapter.startInteraction(at: fpc.state)
+
+        let fullPos = fpc.surfaceLocation(for: .full).y
+        let tipPos = fpc.surfaceLocation(for: .tip).y
+
+        var next: CGFloat
+        fpc.floatingPanel.layoutAdapter.updateInteractiveEdgeConstraint(diff: -100.0,
+                                                                        overflow: false,
+                                                                        allowsRubberBanding: fpc.floatingPanel.behaviorAdapter.allowsRubberBanding(for:))
+        next = fpc.surfaceLocation.y
+        XCTAssertEqual(next, fullPos)
+
+        fpc.floatingPanel.layoutAdapter.updateInteractiveEdgeConstraint(diff: -100.0,
+                                                                        overflow: true,
+                                                                        allowsRubberBanding: fpc.floatingPanel.behaviorAdapter.allowsRubberBanding(for:))
+        next = fpc.surfaceLocation.y
+        XCTAssertEqual(next, fullPos - 100)
+
+        fpc.floatingPanel.layoutAdapter.updateInteractiveEdgeConstraint(diff: tipPos - fullPos + 100.0,
+                                                                        overflow: true,
+                                                                        allowsRubberBanding: fpc.floatingPanel.behaviorAdapter.allowsRubberBanding(for:))
+        next = fpc.surfaceLocation.y
+        XCTAssertEqual(next, tipPos + 100)
+
+        fpc.floatingPanel.layoutAdapter.endInteraction(at: fpc.state)
+    }
+
+    func test_surfaceLocation() {
+        fpc = CustomSafeAreaFloatingPanelController()
+        fpc.loadViewIfNeeded()
+        fpc.view.frame = CGRect(x: 0, y: 0, width: 375, height: 667)
+
+        class MyFloatingPanelFullLayout: FloatingPanelTestLayout {}
+        class MyFloatingPanelSafeAreaLayout: FloatingPanelTestLayout {
+            override var referenceGuide: FloatingPanelLayoutReferenceGuide {
+                return .safeArea
+            }
+        }
+
+        let myLayout = MyFloatingPanelFullLayout()
+        fpc.layout = myLayout
+        fpc.showForTest()
+
+        let bounds = fpc.view!.bounds
+        XCTAssertEqual(fpc.layout.anchors.filter({ $0.value.referenceGuide != .superview }).count, 0)
+        XCTAssertEqual(fpc.surfaceLocation(for: .full).y, myLayout.fullInset)
+        XCTAssertEqual(fpc.surfaceLocation(for: .half).y, bounds.height - myLayout.halfInset)
+        XCTAssertEqual(fpc.surfaceLocation(for: .tip).y, bounds.height - myLayout.tipInset)
+        XCTAssertEqual(fpc.surfaceLocation(for: .hidden).y, bounds.height + 100.0)
+
+        fpc.layout = MyFloatingPanelSafeAreaLayout()
+
+        XCTAssertEqual(fpc.layout.anchors.filter({ $0.value.referenceGuide != .safeArea }).count, 0)
+        XCTAssertEqual(fpc.surfaceLocation(for: .full).y, myLayout.fullInset + fpc.fp_safeAreaInsets.top)
+        XCTAssertEqual(fpc.surfaceLocation(for: .half).y, bounds.height - myLayout.halfInset + fpc.fp_safeAreaInsets.bottom)
+        XCTAssertEqual(fpc.surfaceLocation(for: .tip).y, bounds.height - myLayout.tipInset +  fpc.fp_safeAreaInsets.bottom)
+        XCTAssertEqual(fpc.surfaceLocation(for: .hidden).y, bounds.height + 100.0)
+    }
+
+    func test_surfaceLocation_bottomEdge() {
+        fpc = CustomSafeAreaFloatingPanelController()
+        fpc.loadViewIfNeeded()
+        fpc.view.frame = CGRect(x: 0, y: 0, width: 375, height: 667)
+
+        class MyFloatingPanelFullLayout: FloatingPanelTop2BottomTestLayout { }
+        class MyFloatingPanelSafeAreaLayout: FloatingPanelTop2BottomTestLayout {
+            override var referenceGuide: FloatingPanelLayoutReferenceGuide {
+                return .safeArea
+            }
+        }
+        let myLayout = MyFloatingPanelFullLayout()
+        fpc.layout = myLayout
+        fpc.showForTest()
+
+        let bounds = fpc.view!.bounds
+        XCTAssertEqual(fpc.layout.anchors.filter({ $0.value.referenceGuide != .superview }).count, 0)
+        XCTAssertEqual(fpc.surfaceLocation(for: .full).y, bounds.height - myLayout.fullInset)
+        XCTAssertEqual(fpc.surfaceLocation(for: .half).y, myLayout.halfInset)
+        XCTAssertEqual(fpc.surfaceLocation(for: .tip).y,  myLayout.tipInset)
+        XCTAssertEqual(fpc.surfaceLocation(for: .hidden).y, -100.0)
+
+
+        fpc.layout = MyFloatingPanelSafeAreaLayout()
+
+        XCTAssertEqual(fpc.layout.anchors.filter({ $0.value.referenceGuide != .safeArea }).count, 0)
+        XCTAssertEqual(fpc.surfaceLocation(for: .full).y, bounds.height - myLayout.fullInset + fpc.fp_safeAreaInsets.bottom)
+        XCTAssertEqual(fpc.surfaceLocation(for: .half).y, myLayout.halfInset + fpc.fp_safeAreaInsets.top)
+        XCTAssertEqual(fpc.surfaceLocation(for: .tip).y, myLayout.tipInset + fpc.fp_safeAreaInsets.top)
+        XCTAssertEqual(fpc.surfaceLocation(for: .hidden).y, -100.0)
+    }
+
+    func test_layoutAnchor_topPosition() {
+        let position: FloatingPanelPosition = .top
+        fpc = CustomSafeAreaFloatingPanelController()
+        fpc.loadViewIfNeeded()
+        fpc.view.frame = CGRect(x: 0, y: 0, width: 375, height: 667)
+
+        for prop in [
+            // from top edge
+            (anchor: FloatingPanelLayoutAnchor(absoluteInset: 0.0, edge: .top, referenceGuide: .safeArea),
+             result: (#line, constant: 0.0, firstAnchor: fpc.surfaceView.bottomAnchor, secondAnchor: fpc.fp_safeAreaLayoutGuide.topAnchor)),
+            (anchor: FloatingPanelLayoutAnchor(absoluteInset: 100.0, edge: .top, referenceGuide: .safeArea),
+             result: (#line, constant: 100.0, firstAnchor: fpc.surfaceView.bottomAnchor, secondAnchor: fpc.fp_safeAreaLayoutGuide.topAnchor)),
+            (anchor: FloatingPanelLayoutAnchor(absoluteInset: 0.0, edge: .top, referenceGuide: .superview),
+             result: (#line, constant: 0.0, firstAnchor: fpc.surfaceView.bottomAnchor, secondAnchor: fpc.view.topAnchor)),
+            (anchor: FloatingPanelLayoutAnchor(absoluteInset: 100.0, edge: .top, referenceGuide: .superview),
+             result: (#line, constant: 100.0, firstAnchor: fpc.surfaceView.bottomAnchor, secondAnchor: fpc.view.topAnchor)),
+            // from bottom edge
+            (anchor: FloatingPanelLayoutAnchor(absoluteInset: 0.0, edge: .bottom, referenceGuide: .safeArea),
+             result: (#line, constant: 0.0, firstAnchor: fpc.fp_safeAreaLayoutGuide.bottomAnchor, secondAnchor: fpc.surfaceView.bottomAnchor)),
+            (anchor: FloatingPanelLayoutAnchor(absoluteInset: 100.0, edge: .bottom, referenceGuide: .safeArea),
+             result: (#line, constant: 100.0, firstAnchor: fpc.fp_safeAreaLayoutGuide.bottomAnchor, secondAnchor: fpc.surfaceView.bottomAnchor)),
+            (anchor: FloatingPanelLayoutAnchor(absoluteInset: 0.0, edge: .bottom, referenceGuide: .superview),
+             result: (#line, constant: 0.0, firstAnchor: fpc.view.bottomAnchor, secondAnchor: fpc.surfaceView.bottomAnchor)),
+            (anchor: FloatingPanelLayoutAnchor(absoluteInset: 100.0, edge: .bottom, referenceGuide: .superview),
+             result: (#line, constant: 100.0, firstAnchor: fpc.view.bottomAnchor, secondAnchor: fpc.surfaceView.bottomAnchor)),
+            ] {
+                let c = prop.anchor.layoutConstraints(fpc, for: position)[0]
+                XCTAssertEqual(c.constant, CGFloat(prop.result.constant), line: UInt(prop.result.0))
+                XCTAssertEqual(c.firstAnchor, prop.result.firstAnchor, line: UInt(prop.result.0))
+                XCTAssertEqual(c.secondAnchor, prop.result.secondAnchor, line: UInt(prop.result.0))
+        }
+
+        // fractional
+        for prop in [
+            // from top edge
+            (anchor: FloatingPanelLayoutAnchor(fractionalInset: 0.0, edge: .top, referenceGuide: .safeArea),
+             result: (#line, multiplier: 1.0, secondAnchor: nil)),
+            (anchor: FloatingPanelLayoutAnchor(fractionalInset: 0.5, edge: .top, referenceGuide: .safeArea),
+             result: (#line, multiplier: 0.5, secondAnchor: fpc.fp_safeAreaLayoutGuide.heightAnchor)),
+            (anchor: FloatingPanelLayoutAnchor(fractionalInset: 0.0, edge: .top, referenceGuide: .superview),
+             result: (#line, multiplier: 1.0, secondAnchor: nil)),
+            (anchor: FloatingPanelLayoutAnchor(fractionalInset: 0.5, edge: .top, referenceGuide: .superview),
+             result: (#line, multiplier: 0.5, secondAnchor: fpc.view.heightAnchor)),
+
+            // from bottom edge
+            (anchor: FloatingPanelLayoutAnchor(fractionalInset: 0.0, edge: .bottom, referenceGuide: .safeArea),
+             result: (#line, multiplier: 1.0, secondAnchor: nil)),
+            (anchor: FloatingPanelLayoutAnchor(fractionalInset: 0.5, edge: .bottom, referenceGuide: .safeArea),
+             result: (#line, multiplier: 0.5, secondAnchor: fpc.fp_safeAreaLayoutGuide.heightAnchor)),
+            (anchor: FloatingPanelLayoutAnchor(fractionalInset: 0.0, edge: .bottom, referenceGuide: .superview),
+             result: (#line, multiplier: 1.0, secondAnchor: nil)),
+            (anchor: FloatingPanelLayoutAnchor(fractionalInset: 0.5, edge: .bottom, referenceGuide: .superview),
+             result: (#line, multiplier: 0.5, secondAnchor: fpc.view.heightAnchor)),
+            ] {
+                let c = prop.anchor.layoutConstraints(fpc, for: position)[0]
+                XCTAssertEqual(c.multiplier, CGFloat(prop.result.multiplier), line: UInt(prop.result.0))
+                XCTAssertTrue(c.firstAnchor is NSLayoutAnchor<NSLayoutDimension>, line: UInt(prop.result.0))
+                // On iOS 10, `c.secondAnchor` can't be equal object to `prop.result.secondAnchor`
+                // because there is no safe area  on iOS 10 and `fp_safeAreaLayoutGuide` emulates it.
+                if #available(iOS 11, *) {
+                    XCTAssertEqual(c.secondAnchor, prop.result.secondAnchor, line: UInt(prop.result.0))
+                }
+                print(c)
+        }
+    }
+    func test_layoutAnchor_bottomPosition() {
+        let position: FloatingPanelPosition = .bottom
+
+        fpc = CustomSafeAreaFloatingPanelController()
+        fpc.loadViewIfNeeded()
+        fpc.view.frame = CGRect(x: 0, y: 0, width: 375, height: 667)
+
+        for prop in [
+            // from top edge
+            (anchor: FloatingPanelLayoutAnchor(absoluteInset: 0.0, edge: .top, referenceGuide: .safeArea),
+             result: (#line, constant: 0.0, firstAnchor: fpc.surfaceView.topAnchor, secondAnchor: fpc.fp_safeAreaLayoutGuide.topAnchor)),
+            (anchor: FloatingPanelLayoutAnchor(absoluteInset: 100.0, edge: .top, referenceGuide: .safeArea),
+             result: (#line, constant: 100.0, firstAnchor: fpc.surfaceView.topAnchor, secondAnchor: fpc.fp_safeAreaLayoutGuide.topAnchor)),
+            (anchor: FloatingPanelLayoutAnchor(absoluteInset: 0.0, edge: .top, referenceGuide: .superview),
+             result: (#line, constant: 0.0, firstAnchor: fpc.surfaceView.topAnchor, secondAnchor: fpc.view.topAnchor)),
+            (anchor: FloatingPanelLayoutAnchor(absoluteInset: 100.0, edge: .top, referenceGuide: .superview),
+             result: (#line, constant: 100.0, firstAnchor: fpc.surfaceView.topAnchor, secondAnchor: fpc.view.topAnchor)),
+
+            // from bottom edge
+            (anchor: FloatingPanelLayoutAnchor(absoluteInset: 0.0, edge: .bottom, referenceGuide: .safeArea),
+             result: (#line, constant: 0.0, firstAnchor: fpc.fp_safeAreaLayoutGuide.bottomAnchor, secondAnchor: fpc.surfaceView.topAnchor)),
+            (anchor: FloatingPanelLayoutAnchor(absoluteInset: 100.0, edge: .bottom, referenceGuide: .safeArea),
+             result: (#line, constant: 100.0, firstAnchor: fpc.fp_safeAreaLayoutGuide.bottomAnchor, secondAnchor: fpc.surfaceView.topAnchor)),
+            (anchor: FloatingPanelLayoutAnchor(absoluteInset: 0.0, edge: .bottom, referenceGuide: .superview),
+             result: (#line, constant: 0.0, firstAnchor: fpc.view.bottomAnchor, secondAnchor: fpc.surfaceView.topAnchor)),
+            (anchor: FloatingPanelLayoutAnchor(absoluteInset: 100.0, edge: .bottom, referenceGuide: .superview),
+             result: (#line, constant: 100.0, firstAnchor: fpc.view.bottomAnchor, secondAnchor: fpc.surfaceView.topAnchor)),
+            ] {
+                let c = prop.anchor.layoutConstraints(fpc, for: position)[0]
+                XCTAssertEqual(c.constant, CGFloat(prop.result.constant), line: UInt(prop.result.0))
+                XCTAssertEqual(c.firstAnchor, prop.result.firstAnchor, line: UInt(prop.result.0))
+                XCTAssertEqual(c.secondAnchor, prop.result.secondAnchor, line: UInt(prop.result.0))
+        }
+
+        // fractional
+        for prop in [
+            // from top edge
+            (anchor: FloatingPanelLayoutAnchor(fractionalInset: 0.0, edge: .top, referenceGuide: .safeArea),
+             result: (#line, multiplier: 1.0, secondAnchor: nil)),
+            (anchor: FloatingPanelLayoutAnchor(fractionalInset: 0.5, edge: .top, referenceGuide: .safeArea),
+             result: (#line, multiplier: 0.5, secondAnchor: fpc.fp_safeAreaLayoutGuide.heightAnchor)),
+            (anchor: FloatingPanelLayoutAnchor(fractionalInset: 0.0, edge: .top, referenceGuide: .superview),
+             result: (#line, multiplier: 1.0, secondAnchor: nil)),
+            (anchor: FloatingPanelLayoutAnchor(fractionalInset: 0.5, edge: .top, referenceGuide: .superview),
+             result: (#line, multiplier: 0.5, secondAnchor: fpc.view.heightAnchor)),
+
+            // from bottom edge
+            (anchor: FloatingPanelLayoutAnchor(fractionalInset: 0.0, edge: .bottom, referenceGuide: .safeArea),
+             result: (#line, multiplier: 1.0, secondAnchor: nil)),
+            (anchor: FloatingPanelLayoutAnchor(fractionalInset: 0.5, edge: .bottom, referenceGuide: .safeArea),
+             result: (#line, multiplier: 0.5, secondAnchor: fpc.fp_safeAreaLayoutGuide.heightAnchor)),
+            (anchor: FloatingPanelLayoutAnchor(fractionalInset: 0.0, edge: .bottom, referenceGuide: .superview),
+             result: (#line, multiplier: 1.0, secondAnchor: nil)),
+            (anchor: FloatingPanelLayoutAnchor(fractionalInset: 0.5, edge: .bottom, referenceGuide: .superview),
+             result: (#line, multiplier: 0.5, secondAnchor: fpc.view.heightAnchor)),
+            ] {
+                let c = prop.anchor.layoutConstraints(fpc, for: position)[0]
+                XCTAssertEqual(c.multiplier, CGFloat(prop.result.multiplier), line: UInt(prop.result.0))
+                XCTAssertTrue(c.firstAnchor is NSLayoutAnchor<NSLayoutDimension>, line: UInt(prop.result.0))
+                // On iOS 10, `c.secondAnchor` can't be equal object to `prop.result.secondAnchor`
+                // because there is no safe area  on iOS 10 and `fp_safeAreaLayoutGuide` emulates it.
+                if #available(iOS 11, *) {
+                    XCTAssertEqual(c.secondAnchor, prop.result.secondAnchor, line: UInt(prop.result.0))
+                }
+                print(c)
+        }
+    }
+
+    func test_intrinsicLayoutAnchor_topPosition() {
+        class ContentViewController: UIViewController {
+            class IntrinsicView: UIView {
+                override var intrinsicContentSize: CGSize {
+                    return CGSize(width: UIView.noIntrinsicMetric, height: 420)
+                }
+            }
+            override func loadView() {
+                self.view = IntrinsicView()
+            }
+        }
+        let position: FloatingPanelPosition = .top
+
+        fpc = CustomSafeAreaFloatingPanelController()
+        fpc.loadViewIfNeeded()
+        fpc.view.frame = CGRect(x: 0, y: 0, width: 375, height: 667)
+        let contentVC = ContentViewController()
+        contentVC.loadViewIfNeeded()
+        fpc.set(contentViewController: contentVC)
+
+        for prop in [
+            (anchor: FloatingPanelIntrinsicLayoutAnchor(absoluteOffset: 0.0, referenceGuide: .safeArea),
+             result: (#line, constant: 420, firstAnchor: fpc.surfaceView.bottomAnchor, secondAnchor: fpc.fp_safeAreaLayoutGuide.topAnchor)),
+            (anchor: FloatingPanelIntrinsicLayoutAnchor(absoluteOffset: 42.0, referenceGuide: .safeArea),
+             result: (#line, constant: 420 - 42, firstAnchor: fpc.surfaceView.bottomAnchor, secondAnchor: fpc.fp_safeAreaLayoutGuide.topAnchor)),
+            (anchor: FloatingPanelIntrinsicLayoutAnchor(absoluteOffset: 0.0, referenceGuide: .superview),
+             result: (#line, constant: 420, firstAnchor: fpc.surfaceView.bottomAnchor, secondAnchor: fpc.view.topAnchor)),
+            (anchor: FloatingPanelIntrinsicLayoutAnchor(absoluteOffset: 42.0, referenceGuide: .superview),
+             result: (#line, constant: 420 - 42, firstAnchor: fpc.surfaceView.bottomAnchor, secondAnchor: fpc.view.topAnchor)),
+
+            (anchor: FloatingPanelIntrinsicLayoutAnchor(fractionalOffset: 0.0, referenceGuide: .safeArea),
+             result: (#line, constant: 420, firstAnchor: fpc.surfaceView.bottomAnchor, secondAnchor: fpc.fp_safeAreaLayoutGuide.topAnchor)),
+            (anchor: FloatingPanelIntrinsicLayoutAnchor(fractionalOffset: 0.5, referenceGuide: .safeArea),
+             result: (#line, constant: 210, firstAnchor: fpc.surfaceView.bottomAnchor, secondAnchor: fpc.fp_safeAreaLayoutGuide.topAnchor)),
+            (anchor: FloatingPanelIntrinsicLayoutAnchor(fractionalOffset: 1.0, referenceGuide: .safeArea),
+             result: (#line, constant: 0, firstAnchor: fpc.surfaceView.bottomAnchor, secondAnchor: fpc.fp_safeAreaLayoutGuide.topAnchor)),
+            (anchor: FloatingPanelIntrinsicLayoutAnchor(fractionalOffset: 0.0, referenceGuide: .superview),
+             result: (#line, constant: 420, firstAnchor: fpc.surfaceView.bottomAnchor, secondAnchor: fpc.view.topAnchor)),
+            (anchor: FloatingPanelIntrinsicLayoutAnchor(fractionalOffset: 0.5, referenceGuide: .superview),
+             result: (#line, constant: 210, firstAnchor: fpc.surfaceView.bottomAnchor, secondAnchor: fpc.view.topAnchor)),
+            (anchor: FloatingPanelIntrinsicLayoutAnchor(fractionalOffset: 1.0, referenceGuide: .superview),
+             result: (#line, constant: 0, firstAnchor: fpc.surfaceView.bottomAnchor, secondAnchor: fpc.view.topAnchor)),
+            ] {
+                let c = prop.anchor.layoutConstraints(fpc, for: position)[0]
+                XCTAssertEqual(c.constant, CGFloat(prop.result.constant), line: UInt(prop.result.0))
+                XCTAssertEqual(c.firstAnchor, prop.result.firstAnchor, line: UInt(prop.result.0))
+                XCTAssertEqual(c.secondAnchor, prop.result.secondAnchor, line: UInt(prop.result.0))
+        }
+    }
+
+    func test_intrinsicLayoutAnchor_bottomPosition() {
+        class ContentViewController: UIViewController {
+            class IntrinsicView: UIView {
+                override var intrinsicContentSize: CGSize {
+                    return CGSize(width: UIView.noIntrinsicMetric, height: 420)
+                }
+            }
+            override func loadView() {
+                self.view = IntrinsicView()
+            }
+        }
+        let position: FloatingPanelPosition = .bottom
+
+        fpc = CustomSafeAreaFloatingPanelController()
+        fpc.loadViewIfNeeded()
+        fpc.view.frame = CGRect(x: 0, y: 0, width: 375, height: 667)
+        let contentVC = ContentViewController()
+        contentVC.loadViewIfNeeded()
+        fpc.set(contentViewController: contentVC)
+
+        for prop in [
+            (anchor: FloatingPanelIntrinsicLayoutAnchor(absoluteOffset: 0.0, referenceGuide: .safeArea),
+             result: (#line, constant: -420, firstAnchor: fpc.surfaceView.topAnchor, secondAnchor: fpc.fp_safeAreaLayoutGuide.bottomAnchor)),
+            (anchor: FloatingPanelIntrinsicLayoutAnchor(absoluteOffset: 42.0, referenceGuide: .safeArea),
+             result: (#line, constant: -420 + 42, firstAnchor: fpc.surfaceView.topAnchor, secondAnchor: fpc.fp_safeAreaLayoutGuide.bottomAnchor)),
+            (anchor: FloatingPanelIntrinsicLayoutAnchor(absoluteOffset: 0.0, referenceGuide: .superview),
+             result: (#line, constant: -420, firstAnchor: fpc.surfaceView.topAnchor, secondAnchor: fpc.view.bottomAnchor)),
+            (anchor: FloatingPanelIntrinsicLayoutAnchor(absoluteOffset: 42.0, referenceGuide: .superview),
+             result: (#line, constant: -420 + 42, firstAnchor: fpc.surfaceView.topAnchor, secondAnchor: fpc.view.bottomAnchor)),
+
+            (anchor: FloatingPanelIntrinsicLayoutAnchor(fractionalOffset: 0.0, referenceGuide: .safeArea),
+             result: (#line, constant: -420, firstAnchor: fpc.surfaceView.topAnchor, secondAnchor: fpc.fp_safeAreaLayoutGuide.bottomAnchor)),
+            (anchor: FloatingPanelIntrinsicLayoutAnchor(fractionalOffset: 0.5, referenceGuide: .safeArea),
+             result: (#line, constant: -210, firstAnchor: fpc.surfaceView.topAnchor, secondAnchor: fpc.fp_safeAreaLayoutGuide.bottomAnchor)),
+            (anchor: FloatingPanelIntrinsicLayoutAnchor(fractionalOffset: 1.0, referenceGuide: .safeArea),
+             result: (#line, constant: 0, firstAnchor: fpc.surfaceView.topAnchor, secondAnchor: fpc.fp_safeAreaLayoutGuide.bottomAnchor)),
+            (anchor: FloatingPanelIntrinsicLayoutAnchor(fractionalOffset: 0.0, referenceGuide: .superview),
+             result: (#line, constant: -420, firstAnchor: fpc.surfaceView.topAnchor, secondAnchor: fpc.view.bottomAnchor)),
+            (anchor: FloatingPanelIntrinsicLayoutAnchor(fractionalOffset: 0.5, referenceGuide: .superview),
+             result: (#line, constant: -210, firstAnchor: fpc.surfaceView.topAnchor, secondAnchor: fpc.view.bottomAnchor)),
+            (anchor: FloatingPanelIntrinsicLayoutAnchor(fractionalOffset: 1.0, referenceGuide: .superview),
+             result: (#line, constant: 0, firstAnchor: fpc.surfaceView.topAnchor, secondAnchor: fpc.view.bottomAnchor)),
+            ] {
+                let c = prop.anchor.layoutConstraints(fpc, for: position)[0]
+                XCTAssertEqual(c.constant, CGFloat(prop.result.constant), line: UInt(prop.result.0))
+                XCTAssertEqual(c.firstAnchor, prop.result.firstAnchor, line: UInt(prop.result.0))
+                XCTAssertEqual(c.secondAnchor, prop.result.secondAnchor, line: UInt(prop.result.0))
+        }
+    }
+}
+
+private typealias LayoutSegmentTestParameter = (UInt, pos: CGFloat, forwardY: Bool, lower: FloatingPanelState?, upper: FloatingPanelState?)
+private func assertLayoutSegment(_ floatingPanel: Core, with params: [LayoutSegmentTestParameter]) {
+    params.forEach { (line, pos, forwardY, lowr, upper) in
+        let segment = floatingPanel.layoutAdapter.segment(at: pos, forward: forwardY)
+        XCTAssertEqual(segment.lower, lowr, line: line)
+        XCTAssertEqual(segment.upper, upper, line: line)
+    }
+}
+
+private class CustomSafeAreaFloatingPanelController: FloatingPanelController {
+    override var fp_safeAreaInsets: UIEdgeInsets {
+        return UIEdgeInsets(top: 64.0, left: 0.0, bottom: 0.0, right: 34.0)
+    }
+}

Tests/StateTests.swift

@@ -0,0 +1,24 @@
+// Copyright 2018 the FloatingPanel authors. All rights reserved. MIT license.
+
+import XCTest
+@testable import FloatingPanel
+
+class StateTests: XCTestCase {
+    override func setUp() { }
+    override func tearDown() { }
+
+    func test_nextAndPre() {
+        var positions: [FloatingPanelState]
+        positions = [.full, .half, .tip, .hidden]
+        XCTAssertEqual(FloatingPanelState.full.next(in: positions),  .half)
+        XCTAssertEqual(FloatingPanelState.full.pre(in: positions),  .full)
+        XCTAssertEqual(FloatingPanelState.hidden.next(in: positions), .hidden)
+        XCTAssertEqual(FloatingPanelState.hidden.pre(in: positions), .tip)
+
+        positions = [.full, .hidden]
+        XCTAssertEqual(FloatingPanelState.full.next(in: positions),  .hidden)
+        XCTAssertEqual(FloatingPanelState.full.pre(in: positions),  .full)
+        XCTAssertEqual(FloatingPanelState.hidden.next(in: positions), .hidden)
+        XCTAssertEqual(FloatingPanelState.hidden.pre(in: positions), .full)
+    }
+}

Tests/SurfaceViewTests.swift

@@ -0,0 +1,230 @@
+// Copyright 2018 the FloatingPanel authors. All rights reserved. MIT license.
+
+import XCTest
+@testable import FloatingPanel
+
+class SurfaceViewTests: XCTestCase {
+    override func setUp() {}
+    override func tearDown() {}
+
+    func test_surfaceView() {
+        let surface = SurfaceView(frame: CGRect(x: 0.0, y: 0.0, width: 320.0, height: 480.0))
+        XCTAssertTrue(SurfaceView.requiresConstraintBasedLayout)
+        XCTAssert(surface.contentView == nil)
+        surface.layoutIfNeeded()
+        XCTAssert(surface.grabberHandle.frame.minY == 6.0)
+        XCTAssert(surface.grabberHandle.frame.width == surface.grabberHandleSize.width)
+        XCTAssert(surface.grabberHandle.frame.height == surface.grabberHandleSize.height)
+        surface.backgroundColor = .red
+        surface.layoutIfNeeded()
+        XCTAssert(surface.backgroundColor == surface.containerView.backgroundColor)
+    }
+
+    func test_surfaceView_containerView() {
+        XCTContext.runActivity(named: "Bottom sheet") { _ in
+            let surface = SurfaceView(frame: CGRect(x: 0.0, y: 0.0, width: 320.0, height: 480.0))
+            XCTAssertNil(surface.contentView)
+            surface.layoutIfNeeded()
+
+            let height = surface.bounds.height * 2
+            surface.containerOverflow = height
+            surface.setNeedsLayout()
+            surface.layoutIfNeeded()
+            XCTAssertEqual(surface.containerView.frame, CGRect(x: 0.0, y: 0.0, width: 320.0, height: 480.0 * 3))
+        }
+
+        XCTContext.runActivity(named: "Top sheet") { _ in
+            let surface = SurfaceView(frame: CGRect(x: 0.0, y: 0.0, width: 320.0, height: 480.0))
+            surface.position = .top
+            XCTAssertNil(surface.contentView)
+            surface.layoutIfNeeded()
+
+            let height = surface.bounds.height * 2
+            surface.containerOverflow = height
+            surface.setNeedsLayout()
+            surface.layoutIfNeeded()
+            XCTAssertEqual(surface.containerView.frame, CGRect(x: 0.0, y: -height, width: 320.0, height: 480.0 * 3))
+        }
+    }
+
+    func test_surfaceView_contentView() {
+        XCTContext.runActivity(named: "Bottom sheet") { _ in
+            let surface = SurfaceView(frame: CGRect(x: 0.0, y: 0.0, width: 320.0, height: 480.0))
+            surface.layoutIfNeeded()
+
+            let contentView = UIView()
+            surface.set(contentView: contentView)
+
+            let height = surface.bounds.height * 2
+            surface.containerOverflow = height
+            surface.setNeedsLayout()
+            surface.layoutIfNeeded()
+            XCTAssertEqual(surface.contentView?.frame ?? .zero, surface.bounds)
+        }
+
+        XCTContext.runActivity(named: "Top sheet") { _ in
+            let surface = SurfaceView(frame: CGRect(x: 0.0, y: 0.0, width: 320.0, height: 480.0))
+            surface.position = .top
+            surface.layoutIfNeeded()
+
+            let contentView = UIView()
+            surface.set(contentView: contentView)
+
+            let height = surface.bounds.height * 2
+            surface.containerOverflow = height
+            surface.setNeedsLayout()
+            surface.layoutIfNeeded()
+            XCTAssertEqual(surface.containerView.frame, CGRect(x: 0.0, y: -height, width: 320.0, height: 480.0 * 3))
+            XCTAssertEqual(surface.convert(surface.contentView?.frame ?? .zero, from: surface.containerView),
+                           surface.bounds)
+        }
+    }
+
+
+    func test_surfaceView_grabberHandle() {
+        XCTContext.runActivity(named: "Bottom sheet") { _ in
+            let surface = SurfaceView(frame: CGRect(x: 0.0, y: 0.0, width: 320.0, height: 480.0))
+            XCTAssertNil(surface.contentView)
+            surface.layoutIfNeeded()
+
+            XCTAssertEqual(surface.grabberHandle.frame.minY,  6.0)
+            XCTAssertEqual(surface.grabberHandle.frame.width, surface.grabberHandleSize.width)
+            XCTAssertEqual(surface.grabberHandle.frame.height, surface.grabberHandleSize.height)
+
+            surface.grabberHandlePadding = 10.0
+            surface.grabberHandleSize = CGSize(width: 44.0, height: 12.0)
+            surface.setNeedsLayout()
+            surface.layoutIfNeeded()
+            XCTAssertEqual(surface.grabberHandle.frame.minY,  surface.grabberHandlePadding)
+            XCTAssertEqual(surface.grabberHandle.frame.width, surface.grabberHandleSize.width)
+            XCTAssertEqual(surface.grabberHandle.frame.height, surface.grabberHandleSize.height)
+        }
+
+        XCTContext.runActivity(named: "Top sheet") { _ in
+            let surface = SurfaceView(frame: CGRect(x: 0.0, y: 0.0, width: 320.0, height: 480.0))
+            surface.position = .top
+            XCTAssertNil(surface.contentView)
+            surface.layoutIfNeeded()
+
+            XCTAssertEqual(surface.grabberHandle.frame.maxY, (surface.bounds.maxY - 6.0))
+            XCTAssertEqual(surface.grabberHandle.frame.width, surface.grabberHandleSize.width)
+            XCTAssertEqual(surface.grabberHandle.frame.height, surface.grabberHandleSize.height)
+
+            surface.grabberHandlePadding = 10.0
+            surface.setNeedsLayout()
+            surface.layoutIfNeeded()
+            XCTAssertEqual(surface.grabberHandle.frame.maxY,  surface.bounds.maxY - surface.grabberHandlePadding)
+        }
+    }
+
+    func test_surfaceView_contentMargins() {
+        XCTContext.runActivity(named: "Top sheet") { _ in
+            let surface = SurfaceView(frame: CGRect(x: 0.0, y: 0.0, width: 320.0, height: 480.0))
+            surface.position = .top
+            surface.layoutIfNeeded()
+            XCTAssertEqual(surface.containerView.frame, surface.bounds)
+            surface.containerMargins = UIEdgeInsets(top: 16.0, left: 16.0, bottom: 16.0, right: 16.0)
+            surface.setNeedsLayout()
+            surface.layoutIfNeeded()
+            XCTAssertEqual(surface.containerView.frame, surface.bounds.inset(by: surface.containerMargins))
+        }
+        XCTContext.runActivity(named: "Bottom sheet") { _ in
+            let surface = SurfaceView(frame: CGRect(x: 0.0, y: 0.0, width: 320.0, height: 480.0))
+            surface.layoutIfNeeded()
+            XCTAssertEqual(surface.containerView.frame, surface.bounds)
+            surface.containerMargins = UIEdgeInsets(top: 16.0, left: 16.0, bottom: 16.0, right: 16.0)
+            surface.setNeedsLayout()
+            surface.layoutIfNeeded()
+            XCTAssertEqual(surface.containerView.frame, surface.bounds.inset(by: surface.containerMargins))
+        }
+    }
+
+    func test_surfaceView_contentInsets() {
+        XCTContext.runActivity(named: "Top sheet") { _ in
+            let surface = SurfaceView(frame: CGRect(x: 0.0, y: 0.0, width: 320.0, height: 480.0))
+            surface.position = .top
+            let contentView = UIView()
+            surface.set(contentView: contentView)
+            surface.layoutIfNeeded()
+            XCTAssertEqual(surface.contentView?.frame ?? .zero, surface.bounds)
+            surface.contentPadding = UIEdgeInsets(top: 16.0, left: 16.0, bottom: 16.0, right: 16.0)
+            surface.setNeedsLayout()
+            surface.layoutIfNeeded()
+            XCTAssertEqual(surface.contentView?.frame ?? .zero, surface.bounds.inset(by: surface.contentPadding))
+        }
+        XCTContext.runActivity(named: "Bottom sheet") { _ in
+            let surface = SurfaceView(frame: CGRect(x: 0.0, y: 0.0, width: 320.0, height: 480.0))
+            let contentView = UIView()
+            surface.set(contentView: contentView)
+            surface.layoutIfNeeded()
+            XCTAssertEqual(surface.contentView?.frame ?? .zero, surface.bounds)
+            surface.contentPadding = UIEdgeInsets(top: 16.0, left: 16.0, bottom: 16.0, right: 16.0)
+            surface.setNeedsLayout()
+            surface.layoutIfNeeded()
+            XCTAssertEqual(surface.contentView?.frame ?? .zero, surface.bounds.inset(by: surface.contentPadding))
+        }
+    }
+
+    func test_surfaceView_containerMargins_and_contentInsets() {
+        let surface = SurfaceView(frame: CGRect(x: 0.0, y: 0.0, width: 320.0, height: 480.0))
+        let contentView = UIView()
+        surface.set(contentView: contentView)
+        surface.layoutIfNeeded()
+        XCTAssertEqual(surface.contentView?.frame ?? .zero, surface.bounds)
+        surface.containerMargins = UIEdgeInsets(top: 16.0, left: 16.0, bottom: 16.0, right: 16.0)
+        surface.contentPadding = UIEdgeInsets(top: 16.0, left: 16.0, bottom: 16.0, right: 16.0)
+        surface.setNeedsLayout()
+        surface.layoutIfNeeded()
+        XCTAssertEqual(surface.containerView.frame, surface.bounds.inset(by: surface.containerMargins))
+        XCTAssertEqual(surface.contentView?.frame ?? .zero, surface.containerView.bounds.inset(by: surface.contentPadding))
+    }
+
+    func test_surfaceView_cornderRaduis() {
+        let surface = SurfaceView(frame: CGRect(x: 0.0, y: 0.0, width: 320.0, height: 480.0))
+        XCTAssert(surface.containerView.layer.cornerRadius == 0.0)
+        XCTAssert(surface.containerView.layer.masksToBounds == false)
+
+        let appearance = SurfaceAppearance()
+
+        appearance.cornerRadius = 10.0
+        surface.appearance = appearance
+        surface.layoutIfNeeded()
+        XCTAssert(surface.containerView.layer.cornerRadius == 10.0)
+        XCTAssert(surface.containerView.layer.masksToBounds == true)
+
+        surface.containerView.layer.cornerRadius = 12.0
+        surface.layoutIfNeeded()
+        XCTAssert(surface.containerView.layer.cornerRadius == 12.0)
+        XCTAssert(surface.containerView.layer.masksToBounds == true)
+
+        appearance.cornerRadius = 0.0
+        surface.appearance = appearance
+        surface.layoutIfNeeded()
+        XCTAssert(surface.containerView.layer.cornerRadius == 0.0)
+        XCTAssert(surface.containerView.layer.masksToBounds == false)
+
+        surface.containerView.layer.cornerRadius = 12.0 // Don't change it directly
+        XCTAssert(surface.containerView.layer.cornerRadius == 12.0)
+        XCTAssertFalse(surface.containerView.layer.masksToBounds == true)
+
+        surface.setNeedsLayout()
+        surface.layoutIfNeeded()
+        // Reset corner radius by the current appearance
+        XCTAssert(surface.containerView.layer.cornerRadius == 0.0)
+        XCTAssert(surface.containerView.layer.masksToBounds == false)
+
+    }
+
+    func test_surfaceView_border() {
+        let surface = SurfaceView(frame: CGRect(x: 0.0, y: 0.0, width: 320.0, height: 480.0))
+        XCTAssert(surface.containerView.layer.borderWidth == 0.0)
+
+        let appearance = SurfaceAppearance()
+        appearance.borderColor = .red
+        appearance.borderWidth = 3.0
+        surface.appearance = appearance
+        surface.layoutIfNeeded()
+        XCTAssert(surface.containerView.layer.borderColor == UIColor.red.cgColor)
+        XCTAssert(surface.containerView.layer.borderWidth == 3.0)
+    }
+}

Tests/TestSupports.swift

@@ -0,0 +1,79 @@
+// Copyright 2018 the FloatingPanel authors. All rights reserved. MIT license.
+
+import Foundation
+@testable import FloatingPanel
+
+func waitRunLoop(secs: TimeInterval = 0) {
+    RunLoop.main.run(until: Date(timeIntervalSinceNow: secs))
+}
+
+extension FloatingPanelController {
+    func showForTest() {
+        loadViewIfNeeded()
+        view.frame = CGRect(x: 0, y: 0, width: 375, height: 667)
+        show(animated: false, completion: nil)
+    }
+}
+
+class FloatingPanelTestDelegate: FloatingPanelControllerDelegate {
+    var position: FloatingPanelState = .hidden
+    var didMoveCallback: ((FloatingPanelController) -> Void)?
+    func floatingPanelDidChangePosition(_ vc: FloatingPanelController) {
+        position = vc.state
+    }
+    func floatingPanelDidMove(_ vc: FloatingPanelController) {
+        didMoveCallback?(vc)
+    }
+}
+
+class FloatingPanelTestLayout: FloatingPanelLayout {
+    let fullInset: CGFloat = 20.0
+    let halfInset: CGFloat = 250.0
+    let tipInset: CGFloat = 60.0
+
+    var initialState: FloatingPanelState {
+        return .half
+    }
+    var position: FloatingPanelPosition {
+        return .bottom
+    }
+    var referenceGuide: FloatingPanelLayoutReferenceGuide {
+        return .superview
+    }
+    var anchors: [FloatingPanelState : FloatingPanelLayoutAnchoring] {
+        return [
+            .full: FloatingPanelLayoutAnchor(absoluteInset: fullInset, edge: .top, referenceGuide: referenceGuide),
+            .half: FloatingPanelLayoutAnchor(absoluteInset: halfInset, edge: .bottom, referenceGuide: referenceGuide),
+            .tip: FloatingPanelLayoutAnchor(absoluteInset: tipInset, edge: .bottom, referenceGuide: referenceGuide),
+        ]
+    }
+}
+
+class FloatingPanelTop2BottomTestLayout: FloatingPanelLayout {
+    let fullInset: CGFloat = 0.0
+    let halfInset: CGFloat = 250.0
+    let tipInset: CGFloat = 60.0
+
+    var initialState: FloatingPanelState {
+        return .half
+    }
+    var position: FloatingPanelPosition {
+        return .top
+    }
+    var referenceGuide: FloatingPanelLayoutReferenceGuide {
+        return .superview
+    }
+    var anchors: [FloatingPanelState : FloatingPanelLayoutAnchoring] {
+        return [
+            .full: FloatingPanelLayoutAnchor(absoluteInset: fullInset, edge: .bottom, referenceGuide: referenceGuide),
+            .half: FloatingPanelLayoutAnchor(absoluteInset: halfInset, edge: .top, referenceGuide: referenceGuide),
+            .tip: FloatingPanelLayoutAnchor(absoluteInset: tipInset, edge: .top, referenceGuide: referenceGuide),
+        ]
+    }
+}
+
+class FloatingPanelProjectableBehavior: FloatingPanelBehavior {
+    func shouldProjectMomentum(_ fpc: FloatingPanelController, to proposedTargetPosition: FloatingPanelState) -> Bool {
+        return true
+    }
+}

Tests/TestingApp/AppDelegate.swift

@@ -0,0 +1,19 @@
+// Copyright 2018 the FloatingPanel authors. All rights reserved. MIT license.
+
+import UIKit
+@UIApplicationMain
+class AppDelegate: UIResponder, UIApplicationDelegate {
+    var window: UIWindow?
+
+    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]? = nil) -> Bool {
+        let rootVC = UIViewController(nibName: nil, bundle: nil)
+        rootVC.view.backgroundColor = .gray
+
+        let window = UIWindow()
+        window.rootViewController = rootVC
+        window.makeKeyAndVisible()
+        self.window = window
+
+        return true
+    }
+}

Tests/TestingApp/Info.plist

@@ -0,0 +1,43 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>CFBundleDevelopmentRegion</key>
+	<string>$(DEVELOPMENT_LANGUAGE)</string>
+	<key>CFBundleExecutable</key>
+	<string>$(EXECUTABLE_NAME)</string>
+	<key>CFBundleIdentifier</key>
+	<string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
+	<key>CFBundleInfoDictionaryVersion</key>
+	<string>6.0</string>
+	<key>CFBundleName</key>
+	<string>$(PRODUCT_NAME)</string>
+	<key>CFBundlePackageType</key>
+	<string>APPL</string>
+	<key>CFBundleShortVersionString</key>
+	<string>1.0</string>
+	<key>CFBundleVersion</key>
+	<string>1</string>
+	<key>LSRequiresIPhoneOS</key>
+	<true/>
+	<key>UILaunchStoryboardName</key>
+	<string>LaunchScreen</string>
+	<key>UIRequiredDeviceCapabilities</key>
+	<array>
+		<string>armv7</string>
+	</array>
+	<key>UISupportedInterfaceOrientations</key>
+	<array>
+		<string>UIInterfaceOrientationPortrait</string>
+		<string>UIInterfaceOrientationLandscapeLeft</string>
+		<string>UIInterfaceOrientationLandscapeRight</string>
+	</array>
+	<key>UISupportedInterfaceOrientations~ipad</key>
+	<array>
+		<string>UIInterfaceOrientationPortrait</string>
+		<string>UIInterfaceOrientationPortraitUpsideDown</string>
+		<string>UIInterfaceOrientationLandscapeLeft</string>
+		<string>UIInterfaceOrientationLandscapeRight</string>
+	</array>
+</dict>
+</plist>

Tests/TestingApp/LaunchScreen.storyboard

@@ -0,0 +1,48 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="13142" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" launchScreen="YES" useTraitCollections="YES" useSafeAreas="YES" colorMatched="YES" initialViewController="01J-lp-oVM">
+    <dependencies>
+        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="12042"/>
+        <capability name="Constraints with non-1.0 multipliers" minToolsVersion="5.1"/>
+        <capability name="Safe area layout guides" minToolsVersion="9.0"/>
+        <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
+    </dependencies>
+    <scenes>
+        <!--View Controller-->
+        <scene sceneID="EHf-IW-A2E">
+            <objects>
+                <viewController id="01J-lp-oVM" sceneMemberID="viewController">
+                    <view key="view" contentMode="scaleToFill" id="Ze5-6b-2t3">
+                        <rect key="frame" x="0.0" y="0.0" width="375" height="667"/>
+                        <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
+                        <subviews>
+                            <label opaque="NO" clipsSubviews="YES" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Copyright © 2019 scenee. All rights reserved." textAlignment="center" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" minimumFontSize="9" translatesAutoresizingMaskIntoConstraints="NO" id="obG-Y5-kRd">
+                                <rect key="frame" x="0.0" y="626.5" width="375" height="20.5"/>
+                                <fontDescription key="fontDescription" type="system" pointSize="17"/>
+                                <color key="textColor" red="0.0" green="0.0" blue="0.0" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
+                                <nil key="highlightedColor"/>
+                            </label>
+                            <label opaque="NO" clipsSubviews="YES" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="TestingApp" textAlignment="center" lineBreakMode="middleTruncation" baselineAdjustment="alignBaselines" minimumFontSize="18" translatesAutoresizingMaskIntoConstraints="NO" id="GJd-Yh-RWb">
+                                <rect key="frame" x="0.0" y="202" width="375" height="43"/>
+                                <fontDescription key="fontDescription" type="boldSystem" pointSize="36"/>
+                                <color key="textColor" red="0.0" green="0.0" blue="0.0" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
+                                <nil key="highlightedColor"/>
+                            </label>
+                        </subviews>
+                        <color key="backgroundColor" red="1" green="1" blue="1" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
+                        <constraints>
+                            <constraint firstItem="Bcu-3y-fUS" firstAttribute="centerX" secondItem="obG-Y5-kRd" secondAttribute="centerX" id="5cz-MP-9tL"/>
+                            <constraint firstItem="Bcu-3y-fUS" firstAttribute="centerX" secondItem="GJd-Yh-RWb" secondAttribute="centerX" id="Q3B-4B-g5h"/>
+                            <constraint firstItem="obG-Y5-kRd" firstAttribute="leading" secondItem="Bcu-3y-fUS" secondAttribute="leading" constant="20" symbolic="YES" id="SfN-ll-jLj"/>
+                            <constraint firstAttribute="bottom" secondItem="obG-Y5-kRd" secondAttribute="bottom" constant="20" id="Y44-ml-fuU"/>
+                            <constraint firstItem="GJd-Yh-RWb" firstAttribute="centerY" secondItem="Ze5-6b-2t3" secondAttribute="bottom" multiplier="1/3" constant="1" id="moa-c2-u7t"/>
+                            <constraint firstItem="GJd-Yh-RWb" firstAttribute="leading" secondItem="Bcu-3y-fUS" secondAttribute="leading" constant="20" symbolic="YES" id="x7j-FC-K8j"/>
+                        </constraints>
+                        <viewLayoutGuide key="safeArea" id="Bcu-3y-fUS"/>
+                    </view>
+                </viewController>
+                <placeholder placeholderIdentifier="IBFirstResponder" id="iYj-Kq-Ea1" userLabel="First Responder" sceneMemberID="firstResponder"/>
+            </objects>
+            <point key="canvasLocation" x="53" y="375"/>
+        </scene>
+    </scenes>
+</document>

Tests/UtilTests.swift

@@ -0,0 +1,12 @@
+// Copyright 2018 the FloatingPanel authors. All rights reserved. MIT license.
+
+import XCTest
+@testable import FloatingPanel
+
+class UtilTests: XCTestCase {
+    func test_displayTrunc() {
+        XCTAssertEqual(displayTrunc(333.222, by: 3), 333.3333333333333)
+        XCTAssertNotEqual(displayTrunc(333.5, by: 3), 333.66666666666674)
+        XCTAssertTrue(displayEqual(333.5, 333.66666666666674, by: 3))
+    }
+}