Release v1.6.4

The panel(surface view) could stop b/w anchors if the pan gesture doesn't
pass through `.changed` state after an interruptible animator is interrupted.

The possible reason is the constraints have never changed since the last animation
is committed so that `surfaceView.superview!.layoutIfNeeded()` doesn't trigger
a layout update by the constraint-based layout system in
`FloatingPanelLayoutAdapter.activateLayout(of:)`.

Thus the inserted code changes a panel interactive constraint by the least
positive number. It allows the constraint-based layout system to update the
surface layout expectedly.

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,27 @@
+> Please fill out this template appropriately when filing a bug report.
+>
+> Please remove this line and everything above it before submitting.
+
+### Short description
+
+### Expected behavior
+
+### Actual behavior
+
+### Steps to reproduce
+
+**Code example that reproduces the issue**
+
+### Environment
+
+**Library version**
+
+**Installation method**
+
+- [ ] CocoaPods
+- [ ] Carthage
+- [ ] Git submodules
+
+**iOS version(s)**
+
+**Xcode version**

.gitignore

@@ -22,6 +22,7 @@ xcuserdata/
 *.moved-aside
 *.xccheckout
 *.xcscmblueprint
+*.xcsettings
 
 ## Obj-C/Swift specific
 *.hmap

.travis.yml

@@ -1,45 +1,62 @@
-language: swift
+language: objective-c
 branches:
   only:
     - master
-    - next
 cache:
   directories:
-  - build
-  - vendor
   - /usr/local/Homebrew
   - $HOME/Library/Caches/Homebrew
+before_cache:
+  - brew cleanup
 env:
   global:
   - LANG=en_US.UTF-8
   - LC_ALL=en_US.UTF-8
-skip_cleanup: true
 jobs:
   include:
-  - stage: carthage
+  - stage: "Builds"
+    osx_image: xcode9.4
+    script: xcodebuild -scheme FloatingPanel SWIFT_VERSION=4.1 clean build
+    name: "Swift 4.1"
+  - script: xcodebuild -scheme FloatingPanel SWIFT_VERSION=4.2 clean build
     osx_image: xcode10
+    name: "Swift 4.2"
+  - script: xcodebuild -scheme FloatingPanel SWIFT_VERSION=5.0 clean build
+    osx_image: xcode10.2
+    name: "Swift 5.0"
+
+  - stage: "Tests"
+    osx_image: xcode10.2
+    script: xcodebuild clean test -scheme FloatingPanel -workspace FloatingPanel.xcworkspace -destination 'platform=iOS Simulator,OS=10.3.1,name=iPhone SE'
+    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: xcode10.2
+    name: "iPhone 7 (iOS 11.4)"
+  - script: xcodebuild clean test -scheme FloatingPanel -workspace FloatingPanel.xcworkspace -destination 'platform=iOS Simulator,OS=12.2,name=iPhone X'
+    osx_image: xcode10.2
+    name: "iPhone X (iOS 12.2)"
+
+  - stage: Build examples
+    osx_image: xcode10.2
+    script: xcodebuild -scheme Maps -sdk iphonesimulator clean build
+    name: "Maps"
+  - script: xcodebuild -scheme Stocks -sdk iphonesimulator clean build
+    osx_image: xcode10.2
+    name: "Stocks"
+  - script: xcodebuild -scheme Samples -sdk iphonesimulator clean build
+    osx_image: xcode10.2
+    name: "Samples"
+
+  - stage: Carthage
+    osx_image: xcode10.2
     before_install:
     - brew update
     - brew outdated carthage || brew upgrade carthage
     script:
     - carthage build --no-skip-current
 
-  - stage: podspec
-    osx_image: xcode10
+  - stage: CocoaPods
+    osx_image: xcode10.2
     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
+    - pod spec lint --allow-warnings
+    - pod lib lint --allow-warnings

Examples/Maps/Maps.xcodeproj/project.pbxproj

@@ -312,7 +312,7 @@
 				);
 				PRODUCT_BUNDLE_IDENTIFIER = com.scenee.Maps;
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 4.2;
+				SWIFT_VERSION = 5.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 			};
 			name = Debug;
@@ -331,7 +331,7 @@
 				);
 				PRODUCT_BUNDLE_IDENTIFIER = com.scenee.Maps;
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 4.2;
+				SWIFT_VERSION = 5.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 			};
 			name = Release;

Examples/Maps/Maps/ViewController.swift

@@ -21,7 +21,11 @@ class ViewController: UIViewController, MKMapViewDelegate, UISearchBarDelegate,
 
         // Initialize FloatingPanelController and add the view
         fpc.surfaceView.backgroundColor = .clear
-        fpc.surfaceView.cornerRadius = 9.0
+        if #available(iOS 11, *) {
+            fpc.surfaceView.cornerRadius = 9.0
+        } else {
+            fpc.surfaceView.cornerRadius = 0.0
+        }
         fpc.surfaceView.shadowHidden = false
 
         searchVC = storyboard?.instantiateViewController(withIdentifier: "SearchPanel") as? SearchPanelViewController
@@ -135,7 +139,10 @@ class SearchPanelViewController: UIViewController, UITableViewDataSource, UITabl
     @IBOutlet weak var tableView: UITableView!
     @IBOutlet weak var searchBar: UISearchBar!
     @IBOutlet weak var visualEffectView: UIVisualEffectView!
-    
+
+    // For iOS 10 only
+    private lazy var shadowLayer: CAShapeLayer = CAShapeLayer()
+
     override func viewDidLoad() {
         super.viewDidLoad()
         tableView.dataSource = self
@@ -150,9 +157,24 @@ class SearchPanelViewController: UIViewController, UITableViewDataSource, UITabl
 
     override func viewDidLayoutSubviews() {
         super.viewDidLayoutSubviews()
-        if #available(iOS 10, *) {
+        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
         }
     }
 

Examples/Samples/Samples.xcodeproj/project.pbxproj

@@ -165,6 +165,7 @@
 			isa = PBXNativeTarget;
 			buildConfigurationList = 545DBA1221511E6400CA77B8 /* Build configuration list for PBXNativeTarget "Samples" */;
 			buildPhases = (
+				54D7209621D4DB970054A255 /* ShellScript */,
 				545DB9E621511E6300CA77B8 /* Sources */,
 				545DB9E721511E6300CA77B8 /* Frameworks */,
 				545DB9E821511E6300CA77B8 /* Resources */,
@@ -285,6 +286,26 @@
 		};
 /* End PBXResourcesBuildPhase section */
 
+/* Begin PBXShellScriptBuildPhase section */
+		54D7209621D4DB970054A255 /* ShellScript */ = {
+			isa = PBXShellScriptBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+			);
+			inputFileListPaths = (
+			);
+			inputPaths = (
+			);
+			outputFileListPaths = (
+			);
+			outputPaths = (
+			);
+			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";
+		};
+/* End PBXShellScriptBuildPhase section */
+
 /* Begin PBXSourcesBuildPhase section */
 		545DB9E621511E6300CA77B8 /* Sources */ = {
 			isa = PBXSourcesBuildPhase;
@@ -478,7 +499,7 @@
 				);
 				PRODUCT_BUNDLE_IDENTIFIER = com.scenee.FloatingPanelSample;
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 4.2;
+				SWIFT_VERSION = 5.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 			};
 			name = Debug;
@@ -497,7 +518,7 @@
 				);
 				PRODUCT_BUNDLE_IDENTIFIER = com.scenee.FloatingPanelSample;
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 4.2;
+				SWIFT_VERSION = 5.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 			};
 			name = Release;

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

@@ -14,8 +14,8 @@
         <scene sceneID="Cjh-iX-VQw">
             <objects>
                 <navigationController id="RoN-h0-uBD" sceneMemberID="viewController">
-                    <navigationBar key="navigationBar" contentMode="scaleToFill" insetsLayoutMarginsFromSafeArea="NO" id="hNW-5m-Omi">
-                        <rect key="frame" x="0.0" y="44" width="375" height="44"/>
+                    <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"/>
                     </navigationBar>
                     <connections>
@@ -61,13 +61,19 @@
                         <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="TkN-Oh-wF8" secondAttribute="leading" id="Z6Y-Dc-cei"/>
-                            <constraint firstItem="7IS-PU-x0P" firstAttribute="bottom" secondItem="TkN-Oh-wF8" secondAttribute="bottom" id="fNW-DP-lhV"/>
-                            <constraint firstItem="7IS-PU-x0P" firstAttribute="trailing" secondItem="TkN-Oh-wF8" secondAttribute="trailing" id="vfY-Rc-FOI"/>
+                            <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="trailing" secondItem="39L-Nq-qfp" secondAttribute="trailing" id="vfY-Rc-FOI"/>
                         </constraints>
-                        <viewLayoutGuide key="safeArea" id="TkN-Oh-wF8"/>
+                        <viewLayoutGuide key="safeArea" id="39L-Nq-qfp"/>
                     </view>
-                    <navigationItem key="navigationItem" title="Samples" id="wCF-su-7up"/>
+                    <navigationItem key="navigationItem" title="Samples" id="wCF-su-7up">
+                        <barButtonItem key="rightBarButtonItem" title="Settings" id="rbH-U3-XyA">
+                            <connections>
+                                <action selector="showDebugMenu:" destination="jF4-A0-Eq6" id="j02-db-ZM5"/>
+                            </connections>
+                        </barButtonItem>
+                    </navigationItem>
                     <connections>
                         <outlet property="tableView" destination="7IS-PU-x0P" id="YFM-9W-eP4"/>
                     </connections>
@@ -76,7 +82,87 @@
             </objects>
             <point key="canvasLocation" x="57" y="27"/>
         </scene>
-        <!--Item 2-->
+        <!--Settings View Controller-->
+        <scene sceneID="Bd0-D2-agO">
+            <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"/>
+                        <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"/>
+                                <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"/>
+                                        <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"/>
+                                                <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"/>
+                                        <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>
+                                        </subviews>
+                                    </stackView>
+                                </subviews>
+                            </stackView>
+                        </subviews>
+                        <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="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>
+                        <outlet property="largeTitlesSwicth" destination="js8-Qv-lUC" id="FOm-6k-ffi"/>
+                        <outlet property="translucentSwicth" destination="s6b-j9-8Kw" id="jmf-WH-bzZ"/>
+                        <outlet property="versionLabel" destination="WmC-Tq-NDN" id="Woh-kK-U0m"/>
+                    </connections>
+                </viewController>
+                <placeholder placeholderIdentifier="IBFirstResponder" id="M9h-4V-3M0" userLabel="First Responder" sceneMemberID="firstResponder"/>
+            </objects>
+            <point key="canvasLocation" x="708" y="-200"/>
+        </scene>
+        <!--Layout 2-->
         <scene sceneID="lRc-OZ-sL4">
             <objects>
                 <viewController id="RpE-lI-27a" customClass="TabBarContentViewController" customModule="Samples" customModuleProvider="target" sceneMemberID="viewController">
@@ -84,12 +170,6 @@
                         <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">
                                 <rect key="frame" x="20" y="44" width="39" height="30"/>
                                 <state key="normal" title="Close"/>
@@ -101,20 +181,50 @@
                         </subviews>
                         <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
                         <constraints>
-                            <constraint firstItem="IvG-yp-yzI" firstAttribute="top" secondItem="2Cd-km-qEk" 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="JER-jz-KSq" secondAttribute="centerX" id="hwP-mu-Vmz"/>
-                            <constraint firstItem="IvG-yp-yzI" firstAttribute="leading" secondItem="2Cd-km-qEk" secondAttribute="leading" constant="20" id="pYt-jE-CTF"/>
+                            <constraint firstItem="IvG-yp-yzI" firstAttribute="top" secondItem="954-Dk-zvc" secondAttribute="top" id="18k-sV-PgT"/>
+                            <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="2Cd-km-qEk"/>
+                        <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="326" y="1575"/>
+            <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="roundedRect" 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>
+                        <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>
+                        <viewLayoutGuide key="safeArea" id="0ao-SI-QZW"/>
+                    </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">
@@ -122,12 +232,6 @@
                         <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">
                                 <rect key="frame" x="20" y="44" width="39" height="30"/>
                                 <state key="normal" title="Close"/>
@@ -139,29 +243,28 @@
                         </subviews>
                         <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
                         <constraints>
-                            <constraint firstItem="eFN-tN-4Ct" firstAttribute="leading" secondItem="f88-U8-Vja" 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="eFN-tN-4Ct" firstAttribute="top" secondItem="f88-U8-Vja" secondAttribute="top" id="hUV-3a-XkY"/>
-                            <constraint firstItem="uoW-c8-9wx" firstAttribute="centerX" secondItem="ji9-Ez-N7i" secondAttribute="centerX" id="wDv-OH-7PX"/>
+                            <constraint firstItem="eFN-tN-4Ct" firstAttribute="leading" secondItem="5Ns-4l-Ufg" secondAttribute="leading" constant="20" id="5BT-yZ-EKe"/>
+                            <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"/>
                         </constraints>
-                        <viewLayoutGuide key="safeArea" id="f88-U8-Vja"/>
+                        <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>
-            <point key="canvasLocation" x="-380" y="1576"/>
+            <point key="canvasLocation" x="-962" y="1546"/>
         </scene>
         <!--Intrinsic View Controller-->
         <scene sceneID="wtJ-qZ-aCl">
             <objects>
                 <viewController storyboardIdentifier="IntrinsicViewController" title="Intrinsic View Controller" id="aK0-kv-mTu" sceneMemberID="viewController">
                     <view key="view" contentMode="scaleToFill" id="eLM-xc-d9e">
-                        <rect key="frame" x="0.0" y="0.0" width="375" height="812"/>
+                        <rect key="frame" x="0.0" y="0.0" width="375" height="778"/>
                         <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="68" width="327" height="20.333333333333329"/>
+                                <rect key="frame" x="24" y="24" width="327" height="20.333333333333329"/>
                                 <fontDescription key="fontDescription" type="system" pointSize="17"/>
                                 <nil key="textColor"/>
                                 <nil key="highlightedColor"/>
@@ -169,17 +272,18 @@
                         </subviews>
                         <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
                         <constraints>
-                            <constraint firstItem="vtu-Jb-oOn" firstAttribute="trailing" secondItem="ge4-RW-Gmz" secondAttribute="trailing" constant="24" id="V59-MD-Lcg"/>
+                            <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="vtu-Jb-oOn" secondAttribute="top" constant="24" id="j0s-fd-MYj"/>
+                            <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"/>
                         </constraints>
-                        <viewLayoutGuide key="safeArea" id="vtu-Jb-oOn"/>
+                        <viewLayoutGuide key="safeArea" id="ouu-g9-OiX"/>
                     </view>
+                    <size key="freeformSize" width="375" height="778"/>
                 </viewController>
                 <placeholder placeholderIdentifier="IBFirstResponder" id="DfE-fL-zy5" userLabel="First Responder" sceneMemberID="firstResponder"/>
             </objects>
-            <point key="canvasLocation" x="-940" y="805"/>
+            <point key="canvasLocation" x="2753" y="734"/>
         </scene>
         <!--Tab Bar View Controller-->
         <scene sceneID="nQ5-PV-qFw">
@@ -193,22 +297,23 @@
                     <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"/>
             </objects>
-            <point key="canvasLocation" x="-183" y="806"/>
+            <point key="canvasLocation" x="-706" y="749"/>
         </scene>
         <!--Modal View Controller-->
         <scene sceneID="C9P-Ns-Qrq">
             <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="812"/>
+                        <rect key="frame" x="0.0" y="0.0" width="375" height="778"/>
                         <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="778" width="375" height="34"/>
+                                <rect key="frame" x="0.0" y="744" width="375" height="34"/>
                                 <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">
@@ -254,35 +359,36 @@
                         </subviews>
                         <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
                         <constraints>
-                            <constraint firstItem="sbF-Az-7sy" firstAttribute="top" secondItem="GBa-yx-8to" secondAttribute="top" id="3VR-hj-zeQ"/>
-                            <constraint firstItem="9p4-06-y2T" firstAttribute="top" secondItem="GBa-yx-8to" secondAttribute="top" constant="88" id="41n-Fn-hi3"/>
+                            <constraint firstItem="sbF-Az-7sy" firstAttribute="top" secondItem="kjr-TP-fcM" secondAttribute="top" id="3VR-hj-zeQ"/>
+                            <constraint firstItem="9p4-06-y2T" firstAttribute="top" secondItem="kjr-TP-fcM" secondAttribute="top" constant="88" id="41n-Fn-hi3"/>
                             <constraint firstAttribute="bottom" secondItem="vut-mK-Y4t" secondAttribute="bottom" id="6eq-Kt-heZ"/>
-                            <constraint firstItem="sbF-Az-7sy" firstAttribute="leading" secondItem="GBa-yx-8to" secondAttribute="leading" constant="20" id="T2G-1L-PRs"/>
-                            <constraint firstItem="vut-mK-Y4t" firstAttribute="leading" secondItem="qwo-GK-p1U" secondAttribute="leading" id="gVC-jv-VJX"/>
-                            <constraint firstItem="vut-mK-Y4t" firstAttribute="trailing" secondItem="GBa-yx-8to" secondAttribute="trailing" id="jkq-p2-lUm"/>
-                            <constraint firstItem="9p4-06-y2T" firstAttribute="centerX" secondItem="qwo-GK-p1U" secondAttribute="centerX" id="l8t-p3-ETf"/>
-                            <constraint firstItem="vut-mK-Y4t" firstAttribute="top" secondItem="GBa-yx-8to" secondAttribute="bottom" id="rMy-JT-t4B"/>
+                            <constraint firstItem="sbF-Az-7sy" firstAttribute="leading" secondItem="kjr-TP-fcM" secondAttribute="leading" constant="20" id="T2G-1L-PRs"/>
+                            <constraint firstItem="vut-mK-Y4t" firstAttribute="leading" secondItem="kjr-TP-fcM" secondAttribute="leading" id="gVC-jv-VJX"/>
+                            <constraint firstItem="vut-mK-Y4t" firstAttribute="trailing" secondItem="kjr-TP-fcM" secondAttribute="trailing" id="jkq-p2-lUm"/>
+                            <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="GBa-yx-8to"/>
+                        <viewLayoutGuide key="safeArea" id="kjr-TP-fcM"/>
                     </view>
+                    <size key="freeformSize" width="375" height="778"/>
                     <connections>
                         <outlet property="safeAreaView" destination="vut-mK-Y4t" id="r9P-XF-wLd"/>
                     </connections>
                 </viewController>
                 <placeholder placeholderIdentifier="IBFirstResponder" id="fbi-LZ-M4Y" userLabel="First Responder" sceneMemberID="firstResponder"/>
             </objects>
-            <point key="canvasLocation" x="561" y="806"/>
+            <point key="canvasLocation" x="1375" y="734"/>
         </scene>
         <!--Nested Scroll View Controller-->
         <scene sceneID="TfC-A3-4R0">
             <objects>
                 <viewController storyboardIdentifier="NestedScrollViewController" id="LAe-jm-k6f" customClass="NestedScrollViewController" customModule="Samples" customModuleProvider="target" sceneMemberID="viewController">
                     <view key="view" contentMode="scaleToFill" id="414-Wy-0t1">
-                        <rect key="frame" x="0.0" y="0.0" width="375" height="667"/>
+                        <rect key="frame" x="0.0" y="0.0" width="375" height="778"/>
                         <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                         <subviews>
                             <scrollView clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="sBe-tN-uMi">
-                                <rect key="frame" x="0.0" y="32" width="375" height="635"/>
+                                <rect key="frame" x="0.0" y="32" width="375" height="746"/>
                                 <subviews>
                                     <stackView opaque="NO" contentMode="scaleToFill" axis="vertical" translatesAutoresizingMaskIntoConstraints="NO" id="lFR-Sp-Sj1">
                                         <rect key="frame" x="0.0" y="0.0" width="375" height="968"/>
@@ -358,20 +464,21 @@
                         <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
                         <gestureRecognizers/>
                         <constraints>
-                            <constraint firstItem="sBe-tN-uMi" firstAttribute="leading" secondItem="414-Wy-0t1" secondAttribute="leading" id="8Qd-my-knA"/>
+                            <constraint firstItem="sBe-tN-uMi" firstAttribute="leading" secondItem="ufS-Rf-F2F" secondAttribute="leading" id="8Qd-my-knA"/>
                             <constraint firstItem="sBe-tN-uMi" firstAttribute="top" secondItem="414-Wy-0t1" secondAttribute="top" constant="32" id="9Js-LU-lNr"/>
                             <constraint firstAttribute="bottom" secondItem="sBe-tN-uMi" secondAttribute="bottom" id="jzB-47-P7e"/>
-                            <constraint firstAttribute="trailing" secondItem="sBe-tN-uMi" secondAttribute="trailing" id="nHG-wg-pLP"/>
+                            <constraint firstItem="ufS-Rf-F2F" firstAttribute="trailing" secondItem="sBe-tN-uMi" secondAttribute="trailing" id="nHG-wg-pLP"/>
                         </constraints>
-                        <viewLayoutGuide key="safeArea" id="sL5-d5-za2"/>
+                        <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"/>
                             <outletCollection property="gestureRecognizers" destination="Fvp-Z6-eVc" appends="YES" id="Fds-J5-YCg"/>
                         </connections>
                     </view>
-                    <size key="freeformSize" width="375" height="667"/>
+                    <size key="freeformSize" width="375" height="778"/>
                     <connections>
+                        <outlet property="nestedScrollView" destination="xba-kG-VQ2" id="ddV-kf-37A"/>
                         <outlet property="scrollView" destination="sBe-tN-uMi" id="h4S-Zl-cLO"/>
                     </connections>
                 </viewController>
@@ -392,7 +499,7 @@
                     </connections>
                 </swipeGestureRecognizer>
             </objects>
-            <point key="canvasLocation" x="1311" y="806"/>
+            <point key="canvasLocation" x="2097" y="734"/>
         </scene>
         <!--Detail View Controller-->
         <scene sceneID="b6k-zi-3wn">
@@ -402,8 +509,19 @@
                         <rect key="frame" x="0.0" y="0.0" width="375" height="778"/>
                         <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                         <subviews>
+                            <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="8yw-OC-Ubk">
+                                <rect key="frame" x="0.0" y="690" width="375" height="88"/>
+                                <color key="backgroundColor" white="0.66666666666666663" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
+                                <constraints>
+                                    <constraint firstAttribute="height" constant="88" id="jwV-YU-tXG"/>
+                                </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"/>
+                                <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">
-                                <rect key="frame" x="319" y="12" width="44" height="44"/>
+                                <rect key="frame" x="319" y="44" width="44" height="44"/>
                                 <constraints>
                                     <constraint firstAttribute="height" constant="44" id="0jg-5D-A1F"/>
                                     <constraint firstAttribute="width" constant="44" id="1Cq-PA-wgW"/>
@@ -412,22 +530,8 @@
                                     <action selector="closeWithSender:" destination="YC8-ae-15L" eventType="touchUpInside" id="Z2v-19-S5k"/>
                                 </connections>
                             </button>
-                            <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="8yw-OC-Ubk">
-                                <rect key="frame" x="0.0" y="690" width="375" height="88"/>
-                                <color key="backgroundColor" white="0.66666666666666663" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
-                                <constraints>
-                                    <constraint firstAttribute="height" constant="88" id="jwV-YU-tXG"/>
-                                </constraints>
-                            </view>
-                            <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="Kva-Z7-0qY" customClass="OnSafeAreaView" customModule="Samples" customModuleProvider="target">
-                                <rect key="frame" x="0.0" y="700" width="375" height="44"/>
-                                <color key="backgroundColor" red="0.0078431372550000003" green="0.72156862749999995" blue="0.45882352939999999" alpha="1" colorSpace="calibratedRGB"/>
-                                <constraints>
-                                    <constraint firstAttribute="height" constant="44" id="DQJ-cY-cKx"/>
-                                </constraints>
-                            </view>
                             <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="82"/>
+                                <rect key="frame" x="130.66666666666666" y="132" width="114" height="134"/>
                                 <subviews>
                                     <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="roundedRect" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="c5r-jU-haj">
                                         <rect key="frame" x="0.0" y="0.0" width="114" height="30"/>
@@ -444,25 +548,33 @@
                                             <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">
+                                        <rect key="frame" x="0.0" y="104" width="114" height="30"/>
+                                        <state key="normal" title="Update Layout"/>
+                                        <connections>
+                                            <action selector="buttonPressed:" destination="YC8-ae-15L" eventType="touchUpInside" id="zTb-sq-B6f"/>
+                                        </connections>
+                                    </button>
                                 </subviews>
                             </stackView>
                         </subviews>
                         <color key="backgroundColor" red="1" green="0.83234566450000003" blue="0.47320586440000001" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
                         <gestureRecognizers/>
                         <constraints>
-                            <constraint firstItem="noi-1a-5bZ" firstAttribute="top" secondItem="g7l-kO-y7q" secondAttribute="top" constant="12" id="EQy-cr-F2Y"/>
-                            <constraint firstItem="tP3-oJ-4EB" firstAttribute="centerX" secondItem="g7l-kO-y7q" secondAttribute="centerX" id="EsD-Vf-dNZ"/>
+                            <constraint firstItem="noi-1a-5bZ" firstAttribute="top" secondItem="aOK-7l-cA6" secondAttribute="top" id="EQy-cr-F2Y"/>
+                            <constraint firstItem="tP3-oJ-4EB" firstAttribute="centerX" secondItem="aOK-7l-cA6" secondAttribute="centerX" id="EsD-Vf-dNZ"/>
+                            <constraint firstItem="Kva-Z7-0qY" firstAttribute="top" secondItem="aOK-7l-cA6" secondAttribute="top" id="Fff-HL-4mo"/>
                             <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="tAi-nk-rDB" secondAttribute="leading" id="RiJ-Hb-OOZ"/>
-                            <constraint firstItem="8yw-OC-Ubk" firstAttribute="trailing" secondItem="tAi-nk-rDB" secondAttribute="trailing" id="Sof-yL-mwK"/>
-                            <constraint firstItem="tP3-oJ-4EB" firstAttribute="top" secondItem="tAi-nk-rDB" secondAttribute="top" constant="88" id="Zhb-Ss-epe"/>
-                            <constraint firstItem="Kva-Z7-0qY" firstAttribute="trailing" secondItem="tAi-nk-rDB" secondAttribute="trailing" id="kkp-Yo-FQW"/>
-                            <constraint firstItem="tAi-nk-rDB" firstAttribute="trailing" secondItem="noi-1a-5bZ" secondAttribute="trailing" constant="12" id="lv9-Nf-HNB"/>
-                            <constraint firstItem="Kva-Z7-0qY" firstAttribute="leading" secondItem="tAi-nk-rDB" secondAttribute="leading" id="oVC-i1-TwS"/>
-                            <constraint firstItem="tAi-nk-rDB" 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="8" symbolic="YES" id="vKQ-h9-uKt"/>
+                            <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="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="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"/>
                         </constraints>
-                        <viewLayoutGuide key="safeArea" id="tAi-nk-rDB"/>
+                        <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"/>
@@ -492,7 +604,7 @@
                     </connections>
                 </pongPressGestureRecognizer>
             </objects>
-            <point key="canvasLocation" x="1440.8" y="-23.388305847076463"/>
+            <point key="canvasLocation" x="655" y="734"/>
         </scene>
         <!--Debug Text View Controller-->
         <scene sceneID="Bkq-O7-q4A">
@@ -550,24 +662,26 @@ Section 1.10.33 of "de Finibus Bonorum et Malorum", written by Cicero in 45 BC
                         </subviews>
                         <color key="backgroundColor" white="0.0" alpha="0.0" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
                         <constraints>
-                            <constraint firstItem="rN1-HL-YHv" firstAttribute="leading" secondItem="ix0-2W-gQN" secondAttribute="leading" id="7V3-KL-vXd"/>
+                            <constraint firstItem="rN1-HL-YHv" firstAttribute="leading" secondItem="5ET-zC-lCb" secondAttribute="leading" id="7V3-KL-vXd"/>
                             <constraint firstAttribute="bottom" secondItem="rN1-HL-YHv" secondAttribute="bottom" id="efD-U5-Tet"/>
                             <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="ix0-2W-gQN" secondAttribute="trailing" id="lfg-EE-euw"/>
+                            <constraint firstItem="rN1-HL-YHv" firstAttribute="trailing" secondItem="5ET-zC-lCb" secondAttribute="trailing" id="lfg-EE-euw"/>
                         </constraints>
-                        <viewLayoutGuide key="safeArea" id="ix0-2W-gQN"/>
+                        <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"/>
             </objects>
-            <point key="canvasLocation" x="729" y="-23"/>
+            <point key="canvasLocation" x="-1" y="734"/>
         </scene>
     </scenes>
     <inferredMetricsTieBreakers>
-        <segue reference="3yq-HE-Tgn"/>
+        <segue reference="r1P-2i-NDe"/>
     </inferredMetricsTieBreakers>
 </document>

Examples/Samples/Sources/UIExtensions.swift

@@ -5,21 +5,39 @@
 
 import UIKit
 
-extension UIView {
-    var layoutInsets: UIEdgeInsets {
-        if #available(iOS 11.0, *) {
-            return safeAreaInsets
-        } else {
-            return layoutMargins
-        }
-    }
+protocol LayoutGuideProvider {
+    var topAnchor: NSLayoutYAxisAnchor { get }
+    var bottomAnchor: NSLayoutYAxisAnchor { get }
+}
+extension UILayoutGuide: LayoutGuideProvider {}
 
-    var layoutGuide: UILayoutGuide {
-        if #available(iOS 11.0, *) {
-            return safeAreaLayoutGuide
-        } else {
-            return layoutMarginsGuide
-        }
+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)
+        }
+    }
+}

Examples/Samples/Sources/ViewController.swift

@@ -9,7 +9,7 @@
 import UIKit
 import FloatingPanel
 
-class SampleListViewController: UIViewController, UITableViewDataSource, UITableViewDelegate, FloatingPanelControllerDelegate, FloatingPanelLayout {
+class SampleListViewController: UIViewController {
     @IBOutlet weak var tableView: UITableView!
 
     enum Menu: Int, CaseIterable {
@@ -19,9 +19,11 @@ class SampleListViewController: UIViewController, UITableViewDataSource, UITable
         case showModal
         case showFloatingPanelModal
         case showTabBar
+        case showPageView
         case showNestedScrollView
         case showRemovablePanel
         case showIntrinsicView
+        case showContentInset
 
         var name: String {
             switch self {
@@ -31,9 +33,11 @@ class SampleListViewController: UIViewController, UITableViewDataSource, UITable
             case .showModal: return "Show Modal"
             case .showFloatingPanelModal: return "Show Floating Panel Modal"
             case .showTabBar: return "Show Tab Bar"
+            case .showPageView: return "Show Page 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"
             }
         }
 
@@ -45,16 +49,36 @@ class SampleListViewController: UIViewController, UITableViewDataSource, UITable
             case .showModal: return "ModalViewController"
             case .showFloatingPanelModal: return nil
             case .showTabBar: return "TabBarViewController"
+            case .showPageView: return nil
             case .showNestedScrollView: return "NestedScrollViewController"
             case .showRemovablePanel: return "DetailViewController"
             case .showIntrinsicView: return "IntrinsicViewController"
+            case .showContentInset: return nil
             }
         }
     }
 
+    var currentMenu: Menu = .trackingTableView
+
     var mainPanelVC: FloatingPanelController!
     var detailPanelVC: FloatingPanelController!
-    var currentMenu: Menu = .trackingTableView
+    var settingsPanelVC: FloatingPanelController!
+
+    var mainPanelObserves: [NSKeyValueObservation] = []
+    var settingsObserves: [NSKeyValueObservation] = []
+
+    lazy var pages: [UIViewController] = {
+        let page1 = FloatingPanelController(delegate: self)
+        page1.view.backgroundColor = .blue
+        page1.show()
+        let page2 = FloatingPanelController(delegate: self)
+        page2.view.backgroundColor = .red
+        page2.show()
+        let page3 = FloatingPanelController(delegate: self)
+        page3.view.backgroundColor = .green
+        page3.show()
+        return [page1, page2, page3]
+    }()
 
     override func viewDidLoad() {
         super.viewDidLoad()
@@ -62,15 +86,39 @@ class SampleListViewController: UIViewController, UITableViewDataSource, UITable
         tableView.delegate = self
         tableView.register(UITableViewCell.self, forCellReuseIdentifier: "Cell")
 
+        let searchController = UISearchController(searchResultsController: nil)
+        if #available(iOS 11.0, *) {
+            navigationItem.searchController = searchController
+            navigationItem.hidesSearchBarWhenScrolling = false
+            navigationItem.largeTitleDisplayMode = .automatic
+        } else {
+            // Fallback on earlier versions
+        }
+
         let contentVC = DebugTableViewController()
         addMainPanel(with: contentVC)
     }
 
     override func viewDidAppear(_ animated: Bool) {
         super.viewDidAppear(animated)
+
+        if #available(iOS 11.0, *) {
+            if let observation = navigationController?.navigationBar.observe(\.prefersLargeTitles, changeHandler: { (bar, _) in
+                self.tableView.reloadData()
+            }) {
+                settingsObserves.append(observation)
+            }
+        }
+    }
+
+    override func viewWillDisappear(_ animated: Bool) {
+        super.viewWillDisappear(animated)
+        settingsObserves.removeAll()
     }
 
     func addMainPanel(with contentVC: UIViewController) {
+        mainPanelObserves.removeAll()
+
         // Initialize FloatingPanelController
         mainPanelVC = FloatingPanelController()
         mainPanelVC.delegate = self
@@ -84,6 +132,11 @@ class SampleListViewController: UIViewController, UITableViewDataSource, UITable
 
         // Enable tap-to-hide and removal interaction
         switch currentMenu {
+        case .trackingTableView:
+            let tapGesture = UITapGestureRecognizer(target: self, action: #selector(handleSurface(tapGesture:)))
+            tapGesture.cancelsTouchesInView = false
+            tapGesture.numberOfTapsRequired = 2
+            mainPanelVC.surfaceView.addGestureRecognizer(tapGesture)
         case .showRemovablePanel, .showIntrinsicView:
             mainPanelVC.isRemovalInteractionEnabled = true
 
@@ -99,6 +152,10 @@ class SampleListViewController: UIViewController, UITableViewDataSource, UITable
             mainPanelVC.track(scrollView: consoleVC.textView)
 
         case let contentVC as DebugTableViewController:
+            let ob = contentVC.tableView.observe(\.isEditing) { (tableView, _) in
+                self.mainPanelVC.panGestureRecognizer.isEnabled = !tableView.isEditing
+            }
+            mainPanelObserves.append(ob)
             mainPanelVC.track(scrollView: contentVC.tableView)
         case let contentVC as NestedScrollViewController:
             mainPanelVC.track(scrollView: contentVC.scrollView)
@@ -110,30 +167,82 @@ class SampleListViewController: UIViewController, UITableViewDataSource, UITable
         mainPanelVC.addPanel(toParent: self, belowView: nil, animated: true)
     }
 
-    @objc func dismissDetailPanelVC()  {
-        detailPanelVC.removePanelFromParent(animated: true, completion: nil)
+    @objc
+    func handleSurface(tapGesture: UITapGestureRecognizer) {
+        switch mainPanelVC.position {
+        case .full:
+            mainPanelVC.move(to: .half, animated: true)
+        default:
+            mainPanelVC.move(to: .full, animated: true)
+        }
     }
 
     @objc func handleBackdrop(tapGesture: UITapGestureRecognizer) {
-        mainPanelVC.hide(animated: true, completion: nil)
+        switch tapGesture.view {
+        case mainPanelVC.backdropView:
+            mainPanelVC.hide(animated: true, completion: nil)
+        case settingsPanelVC.backdropView:
+            settingsPanelVC.removePanelFromParent(animated: true)
+            settingsPanelVC = nil
+        default:
+            break
+        }
     }
 
-    // MARK:- TableViewDatasource
+    // MARK:- Actions
+    @IBAction func showDebugMenu(_ sender: UIBarButtonItem) {
+        guard settingsPanelVC == nil else { return }
+        // Initialize FloatingPanelController
+        settingsPanelVC = FloatingPanelController()
 
+        // Initialize FloatingPanelController and add the view
+        settingsPanelVC.surfaceView.cornerRadius = 6.0
+        settingsPanelVC.surfaceView.shadowHidden = false
+        settingsPanelVC.isRemovalInteractionEnabled = true
+
+        let backdropTapGesture = UITapGestureRecognizer(target: self, action: #selector(handleBackdrop(tapGesture:)))
+        settingsPanelVC.backdropView.addGestureRecognizer(backdropTapGesture)
+
+        settingsPanelVC.delegate = self
+
+        let contentVC = storyboard?.instantiateViewController(withIdentifier: "SettingsViewController")
+
+        // Set a content view controller
+        settingsPanelVC.set(contentViewController: contentVC)
+
+        //  Add FloatingPanel to self.view
+        settingsPanelVC.addPanel(toParent: self, belowView: nil, animated: true)
+    }
+}
+
+extension SampleListViewController: UITableViewDataSource {
     func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
-        return Menu.allCases.count
+        if #available(iOS 11.0, *) {
+            if navigationController?.navigationBar.prefersLargeTitles == true {
+                return Menu.allCases.count + 30
+            } else {
+                return Menu.allCases.count
+            }
+        } else {
+            return Menu.allCases.count
+        }
     }
 
     func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
         let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath)
-        let menu = Menu.allCases[indexPath.row]
-        cell.textLabel?.text = menu.name
+        if Menu.allCases.count > indexPath.row {
+            let menu = Menu.allCases[indexPath.row]
+            cell.textLabel?.text = menu.name
+        } else {
+            cell.textLabel?.text = "\(indexPath.row) row"
+        }
         return cell
     }
+}
 
-    // MARK:- TableViewDelegate
-
+extension SampleListViewController: UITableViewDelegate {
     func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
+        guard Menu.allCases.count > indexPath.row else { return }
         let menu = Menu.allCases[indexPath.row]
         let contentVC: UIViewController = {
             guard let storyboardID = menu.storyboardID else { return DebugTableViewController() }
@@ -146,7 +255,7 @@ class SampleListViewController: UIViewController, UITableViewDataSource, UITable
         switch menu {
         case .showDetail:
             detailPanelVC?.removePanelFromParent(animated: false)
-            
+
             // Initialize FloatingPanelController
             detailPanelVC = FloatingPanelController()
 
@@ -162,6 +271,22 @@ class SampleListViewController: UIViewController, UITableViewDataSource, UITable
         case .showModal, .showTabBar:
             let modalVC = contentVC
             present(modalVC, animated: true, completion: nil)
+
+        case .showPageView:
+            let pageVC = UIPageViewController(transitionStyle: .scroll, navigationOrientation: .horizontal, options: [:])
+            let closeButton = UIButton(type: .custom)
+            pageVC.view.addSubview(closeButton)
+            closeButton.setTitle("Close", for: .normal)
+            closeButton.translatesAutoresizingMaskIntoConstraints = false
+            closeButton.addTarget(self, action: #selector(dismissPresentedVC), for: .touchUpInside)
+            NSLayoutConstraint.activate([
+                closeButton.topAnchor.constraint(equalTo: pageVC.layoutGuide.topAnchor, constant: 16.0),
+                closeButton.leftAnchor.constraint(equalTo: pageVC.view.leftAnchor, constant: 16.0),
+                ])
+            pageVC.dataSource = self
+            pageVC.setViewControllers([pages[0]], direction: .forward, animated: false, completion: nil)
+            present(pageVC, animated: true, completion: nil)
+
         case .showFloatingPanelModal:
             let fpc = FloatingPanelController()
             let contentVC = self.storyboard!.instantiateViewController(withIdentifier: "DetailViewController")
@@ -174,6 +299,18 @@ class SampleListViewController: UIViewController, UITableViewDataSource, UITable
             fpc.isRemovalInteractionEnabled = true
 
             self.present(fpc, animated: true, completion: nil)
+            
+        case .showContentInset:
+            let contentViewController = UIViewController()
+            contentViewController.view.backgroundColor = .green
+            
+            let fpc = FloatingPanelController()
+            fpc.set(contentViewController: contentViewController)
+            fpc.surfaceView.contentInsets = .init(top: 20, left: 20, bottom: 0, right: 20)
+            
+            fpc.delegate = self
+            fpc.isRemovalInteractionEnabled = true
+            self.present(fpc, animated: true, completion: nil)
         default:
             detailPanelVC?.removePanelFromParent(animated: true, completion: nil)
             mainPanelVC?.removePanelFromParent(animated: true) {
@@ -182,7 +319,17 @@ class SampleListViewController: UIViewController, UITableViewDataSource, UITable
         }
     }
 
+    @objc func dismissPresentedVC() {
+        self.presentedViewController?.dismiss(animated: true, completion: nil)
+    }
+}
+
+extension SampleListViewController: FloatingPanelControllerDelegate {
     func floatingPanel(_ vc: FloatingPanelController, layoutFor newCollection: UITraitCollection) -> FloatingPanelLayout? {
+        if vc == settingsPanelVC {
+            return IntrinsicPanelLayout()
+        }
+
         switch currentMenu {
         case .showRemovablePanel:
             return newCollection.verticalSizeClass == .compact ? RemovablePanelLandscapeLayout() :  RemovablePanelLayout()
@@ -198,6 +345,34 @@ class SampleListViewController: UIViewController, UITableViewDataSource, UITable
         }
     }
 
+    func floatingPanel(_ vc: FloatingPanelController, shouldRecognizeSimultaneouslyWith gestureRecognizer: UIGestureRecognizer) -> Bool {
+        switch currentMenu {
+        case .showNestedScrollView:
+            return (vc.contentViewController as? NestedScrollViewController)?.nestedScrollView.gestureRecognizers?.contains(gestureRecognizer) ?? false
+        case .showPageView:
+            // Tips: Need to allow recognizing the pan gesture of UIPageViewController simultaneously.
+            return true
+        default:
+            return false
+        }
+    }
+
+    func floatingPanelDidEndRemove(_ vc: FloatingPanelController) {
+        switch vc {
+        case settingsPanelVC:
+            settingsPanelVC = nil
+        default:
+            break
+        }
+    }
+}
+
+/**
+ - Attention: `FloatingPanelLayout` must not be applied by the parent view
+ controller of a floating panel. But here `SampleListViewController` adopts it
+ purposely to check if the library prints an appropriate warning.
+ */
+extension SampleListViewController: FloatingPanelLayout {
     var initialPosition: FloatingPanelPosition {
         return .half
     }
@@ -212,12 +387,32 @@ class SampleListViewController: UIViewController, UITableViewDataSource, UITable
     }
 }
 
+extension SampleListViewController: UIPageViewControllerDataSource {
+    func pageViewController(_ pageViewController: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController? {
+        guard
+            let index = pages.firstIndex(of: viewController),
+            index + 1 < pages.count
+            else { return nil }
+        return pages[index + 1]
+    }
+    func pageViewController(_ pageViewController: UIPageViewController, viewControllerBefore viewController: UIViewController) -> UIViewController? {
+        guard
+            let index = pages.firstIndex(of: viewController),
+            index - 1 >= 0
+            else { return nil }
+        return pages[index - 1]
+    }
+}
+
 class IntrinsicPanelLayout: FloatingPanelIntrinsicLayout { }
 
 class RemovablePanelLayout: FloatingPanelIntrinsicLayout {
     var supportedPositions: Set<FloatingPanelPosition> {
         return [.full, .half]
     }
+    var initialPosition: FloatingPanelPosition {
+        return .half
+    }
     var topInteractionBuffer: CGFloat {
         return 200.0
     }
@@ -265,6 +460,7 @@ class ModalPanelLayout: FloatingPanelIntrinsicLayout {
 
 class NestedScrollViewController: UIViewController {
     @IBOutlet weak var scrollView: UIScrollView!
+    @IBOutlet weak var nestedScrollView: UIScrollView!
 
     @IBAction func longPressed(_ sender: Any) {
         print("LongPressed!")
@@ -279,16 +475,32 @@ class NestedScrollViewController: UIViewController {
 
 class DebugTextViewController: UIViewController, UITextViewDelegate {
     @IBOutlet weak var textView: UITextView!
+    @IBOutlet weak var textViewTopConstraint: NSLayoutConstraint!
 
     override func viewDidLoad() {
         super.viewDidLoad()
         textView.delegate = self
+        print("viewDidLoad: TextView --- ", textView.contentOffset, textView.contentInset)
 
         if #available(iOS 11.0, *) {
             textView.contentInsetAdjustmentBehavior = .never
         }
     }
 
+    override func viewWillLayoutSubviews() {
+        print("viewWillLayoutSubviews: TextView --- ", textView.contentOffset, textView.contentInset, textView.frame)
+    }
+
+    override func viewDidLayoutSubviews() {
+        super.viewDidLayoutSubviews()
+        print("viewDidLayoutSubviews: TextView --- ", textView.contentOffset, textView.contentInset, textView.frame)
+    }
+
+    override func viewDidAppear(_ animated: Bool) {
+        super.viewDidAppear(animated)
+        print("TextView --- ", textView.contentOffset, textView.contentInset, textView.frame)
+    }
+
     func scrollViewDidScroll(_ scrollView: UIScrollView) {
         print("TextView --- ", scrollView.contentOffset, scrollView.contentInset)
         if #available(iOS 11.0, *) {
@@ -302,10 +514,63 @@ class DebugTextViewController: UIViewController, UITextViewDelegate {
     }
 }
 
-class DebugTableViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {
+class InspectableViewController: UIViewController {
+    override func viewWillLayoutSubviews() {
+        super.viewWillLayoutSubviews()
+        print(">>> Content View: viewWillLayoutSubviews", layoutInsets)
+    }
+
+    override func viewDidLayoutSubviews() {
+        super.viewDidLayoutSubviews()
+        print(">>> Content View: viewDidLayoutSubviews", layoutInsets)
+    }
+
+    override func viewWillAppear(_ animated: Bool) {
+        super.viewWillAppear(animated)
+        print(">>> Content View: viewWillAppear", layoutInsets)
+    }
+
+    override func viewDidAppear(_ animated: Bool) {
+        super.viewDidAppear(animated)
+        print(">>> Content View: viewDidAppear", view.bounds, layoutInsets)
+    }
+
+    override func viewWillDisappear(_ animated: Bool) {
+        super.viewWillDisappear(animated)
+        print(">>> Content View: viewWillDisappear")
+    }
+
+    override func viewDidDisappear(_ animated: Bool) {
+        super.viewDidDisappear(animated)
+        print(">>> Content View: viewDidDisappear")
+    }
+
+    override func willMove(toParent parent: UIViewController?) {
+        super.willMove(toParent: parent)
+        print(">>> Content View: willMove(toParent: \(String(describing: parent))")
+    }
+
+    override func didMove(toParent parent: UIViewController?) {
+        super.didMove(toParent: parent)
+        print(">>> Content View: didMove(toParent: \(String(describing: parent))")
+    }
+    public override func willTransition(to newCollection: UITraitCollection, with coordinator: UIViewControllerTransitionCoordinator) {
+        print(">>> Content View: willTransition(to: \(newCollection), with: \(coordinator))", layoutInsets)
+    }
+}
+
+class DebugTableViewController: InspectableViewController {
     weak var tableView: UITableView!
     var items: [String] = []
     var itemHeight: CGFloat = 66.0
+
+    enum Menu: String, CaseIterable {
+        case animateScroll = "Animate Scroll"
+        case changeContentSize = "Change content size"
+        case reorder = "Reorder"
+    }
+
+    var reorderButton: UIButton!
     override func viewDidLoad() {
         super.viewDidLoad()
 
@@ -335,17 +600,21 @@ class DebugTableViewController: UIViewController, UITableViewDataSource, UITable
             stackView.rightAnchor.constraint(equalTo: view.rightAnchor, constant: -22.0),
             ])
 
-        let button = UIButton()
-        button.setTitle("Animate Scroll", for: .normal)
-        button.setTitleColor(view.tintColor, for: .normal)
-        button.addTarget(self, action: #selector(animateScroll), for: .touchUpInside)
-        stackView.addArrangedSubview(button)
-
-        let button2 = UIButton()
-        button2.setTitle("Change content size", for: .normal)
-        button2.setTitleColor(view.tintColor, for: .normal)
-        button2.addTarget(self, action: #selector(changeContentSize), for: .touchUpInside)
-        stackView.addArrangedSubview(button2)
+        for menu in Menu.allCases {
+            let button = UIButton()
+            button.setTitle(menu.rawValue, for: .normal)
+            button.setTitleColor(view.tintColor, for: .normal)
+            switch menu {
+            case .animateScroll:
+                button.addTarget(self, action: #selector(animateScroll), for: .touchUpInside)
+            case .changeContentSize:
+                button.addTarget(self, action: #selector(changeContentSize), for: .touchUpInside)
+            case .reorder:
+                button.addTarget(self, action: #selector(reorderItems), for: .touchUpInside)
+                reorderButton = button
+            }
+            stackView.addArrangedSubview(button)
+        }
 
         for i in 0...100 {
             items.append("Items \(i)")
@@ -386,6 +655,16 @@ class DebugTableViewController: UIViewController, UITableViewDataSource, UITable
         self.present(actionSheet, animated: true, completion: nil)
     }
 
+    @objc func reorderItems() {
+        if reorderButton.titleLabel?.text == Menu.reorder.rawValue {
+            tableView.isEditing = true
+            reorderButton.setTitle("Cancel", for: .normal)
+        } else {
+            tableView.isEditing = false
+            reorderButton.setTitle(Menu.reorder.rawValue, for: .normal)
+        }
+    }
+
     func changeItems(_ count: Int) {
         items.removeAll()
         for i in 0..<count {
@@ -399,50 +678,12 @@ class DebugTableViewController: UIViewController, UITableViewDataSource, UITable
         (self.parent as! FloatingPanelController).removePanelFromParent(animated: true, completion: nil)
     }
 
-    override func viewWillLayoutSubviews() {
-        super.viewWillLayoutSubviews()
-        //print("Content View: viewWillLayoutSubviews")
-    }
-
-    override func viewDidLayoutSubviews() {
-        super.viewDidLayoutSubviews()
-        //print("Content View: viewDidLayoutSubviews")
-    }
-
-    override func viewWillAppear(_ animated: Bool) {
-        super.viewWillAppear(animated)
-        print("Content View: viewWillAppear")
-    }
-
-    override func viewDidAppear(_ animated: Bool) {
-        super.viewDidAppear(animated)
-        print("Content View: viewDidAppear", view.bounds)
-    }
-
-    override func viewWillDisappear(_ animated: Bool) {
-        super.viewWillDisappear(animated)
-        print("Content View: viewWillDisappear")
-    }
-
-    override func viewDidDisappear(_ animated: Bool) {
-        super.viewDidDisappear(animated)
-        print("Content View: viewDidDisappear")
-    }
-
-    override func willMove(toParent parent: UIViewController?) {
-        super.willMove(toParent: parent)
-        print("Content View: willMove(toParent: \(String(describing: parent))")
-    }
-
-    override func didMove(toParent parent: UIViewController?) {
-        super.didMove(toParent: parent)
-        print("Content View: didMove(toParent: \(String(describing: parent))")
-    }
-
-    public override func willTransition(to newCollection: UITraitCollection, with coordinator: UIViewControllerTransitionCoordinator) {
-        print("Content View: willTransition(to: \(newCollection), with: \(coordinator))")
+    func scrollViewDidScroll(_ scrollView: UIScrollView) {
+        print("TableView --- ", scrollView.contentOffset, scrollView.contentInset)
     }
+}
 
+extension DebugTableViewController: UITableViewDataSource {
     func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
         return items.count
     }
@@ -456,6 +697,12 @@ class DebugTableViewController: UIViewController, UITableViewDataSource, UITable
         cell.textLabel?.text = items[indexPath.row]
         return cell
     }
+}
+
+extension DebugTableViewController: UITableViewDelegate {
+    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
+        print("DebugTableViewController -- select row \(indexPath.row)")
+    }
 
     func tableView(_ tableView: UITableView, editActionsForRowAt indexPath: IndexPath) -> [UITableViewRowAction]? {
         return [
@@ -465,9 +712,17 @@ class DebugTableViewController: UIViewController, UITableViewDataSource, UITable
             }),
         ]
     }
+
+    func tableView(_ tableView: UITableView, canMoveRowAt indexPath: IndexPath) -> Bool {
+        return true
+    }
+
+    func tableView(_ tableView: UITableView, moveRowAt sourceIndexPath: IndexPath, to destinationIndexPath: IndexPath) {
+        items.insert(items.remove(at: sourceIndexPath.row), at: destinationIndexPath.row)
+    }
 }
 
-class DetailViewController: UIViewController {
+class DetailViewController: InspectableViewController {
     @IBOutlet weak var closeButton: UIButton!
     @IBAction func close(sender: UIButton) {
         // (self.parent as? FloatingPanelController)?.removePanelFromParent(animated: true, completion: nil)
@@ -574,10 +829,24 @@ class ModalSecondLayout: FloatingPanelLayout {
 
 class TabBarViewController: UITabBarController {}
 
-class TabBarContentViewController: UIViewController, FloatingPanelControllerDelegate {
+class TabBarContentViewController: UIViewController {
+    enum Tab3Mode {
+        case changeOffset
+        case changeAutoLayout
+        var label: String {
+            switch self {
+            case .changeAutoLayout: return "Use AutoLayout(OK)"
+            case .changeOffset: return "Use ContentOffset(NG)"
+            }
+        }
+    }
     var fpc: FloatingPanelController!
     var consoleVC: DebugTextViewController!
 
+    var threeLayout: ThreeTabBarPanelLayout!
+    var tab3Mode: Tab3Mode = .changeAutoLayout
+    var switcherLabel: UILabel!
+
     override func viewWillAppear(_ animated: Bool) {
         super.viewWillAppear(animated)
         // Initialize FloatingPanelController
@@ -591,11 +860,47 @@ class TabBarContentViewController: UIViewController, FloatingPanelControllerDele
         // Set a content view controller and track the scroll view
         let consoleVC = storyboard?.instantiateViewController(withIdentifier: "ConsoleViewController") as! DebugTextViewController
         fpc.set(contentViewController: consoleVC)
+        consoleVC.textView.delegate = self // MUST call it before fpc.track(scrollView:)
         fpc.track(scrollView: consoleVC.textView)
         self.consoleVC = consoleVC
 
         //  Add FloatingPanel to self.view
         fpc.addPanel(toParent: self)
+
+
+        if tabBarItem.tag == 2 {
+            let switcher = UISwitch()
+            fpc.view.addSubview(switcher)
+            switcher.translatesAutoresizingMaskIntoConstraints = false
+            NSLayoutConstraint.activate([
+                switcher.bottomAnchor.constraint(equalTo: fpc.surfaceView.topAnchor, constant: -16.0),
+                switcher.rightAnchor.constraint(equalTo: fpc.surfaceView.rightAnchor, constant: -16.0),
+                ])
+            switcher.isOn = true
+            switcher.tintColor = .white
+            switcher.backgroundColor = .white
+            switcher.layer.cornerRadius = 16.0
+            switcher.addTarget(self,
+                               action: #selector(changeTab3Mode(_:)),
+                               for: .valueChanged)
+            let label = UILabel()
+            label.text = tab3Mode.label
+            fpc.view.addSubview(label)
+            switcherLabel = label
+            label.translatesAutoresizingMaskIntoConstraints = false
+            NSLayoutConstraint.activate([
+                label.centerYAnchor.constraint(equalTo: switcher.centerYAnchor, constant: 0.0),
+                label.rightAnchor.constraint(equalTo: switcher.leftAnchor, constant: -16.0),
+                ])
+
+            // Turn off the mask instead of content inset change
+            consoleVC.textView.clipsToBounds = false
+        }
+    }
+
+    override func viewDidAppear(_ animated: Bool) {
+        super.viewDidAppear(animated)
+        fpc.updateLayout()
     }
 
     override func viewWillDisappear(_ animated: Bool) {
@@ -604,19 +909,143 @@ class TabBarContentViewController: UIViewController, FloatingPanelControllerDele
         fpc.removePanelFromParent(animated: false)
     }
 
+    // MARK: - Action
+
+    @IBAction func close(sender: UIButton) {
+        dismiss(animated: true, completion: nil)
+    }
+
+    // MARK: - Private
+
+    @objc
+    private func changeTab3Mode(_ sender: UISwitch) {
+        if sender.isOn {
+            tab3Mode = .changeAutoLayout
+        } else {
+            tab3Mode = .changeOffset
+        }
+        switcherLabel.text = tab3Mode.label
+    }
+}
+
+extension TabBarContentViewController: UITextViewDelegate {
+    func scrollViewDidScroll(_ scrollView: UIScrollView) {
+        guard self.tabBarItem.tag == 2 else { return }
+        // Reset an invalid content offset by a user after updating the layout
+        // of `consoleVC.textView`.
+        // NOTE: FloatingPanel doesn't implicitly reset the offset(i.e.
+        // Using KVO of `scrollView.contentOffset`). Because it can lead to an
+        // infinite loop if a user also resets a content offset as below and,
+        // in the situation, a user has to modify the library.
+        if fpc.position != .full, fpc.surfaceView.frame.minY > fpc.originYOfSurface(for: .full) {
+            scrollView.contentOffset = .zero
+        }
+    }
+}
+
+extension TabBarContentViewController: FloatingPanelControllerDelegate {
+    // MARK: - FloatingPanel
+
     func floatingPanel(_ vc: FloatingPanelController, layoutFor newCollection: UITraitCollection) -> FloatingPanelLayout? {
         switch self.tabBarItem.tag {
         case 0:
             return OneTabBarPanelLayout()
         case 1:
-            return TwoTabBarPanel2Layout()
+            return TwoTabBarPanelLayout()
+        case 2:
+            threeLayout = ThreeTabBarPanelLayout(parent: self)
+            return threeLayout
         default:
             return nil
         }
     }
 
-    @IBAction func close(sender: UIButton) {
-        dismiss(animated: true, completion: nil)
+    func floatingPanel(_ vc: FloatingPanelController, behaviorFor newCollection: UITraitCollection) -> FloatingPanelBehavior? {
+        switch self.tabBarItem.tag {
+        case 1:
+            return TwoTabBarPanelBehavior()
+        default:
+            return nil
+        }
+    }
+
+    func floatingPanelDidMove(_ vc: FloatingPanelController) {
+        guard self.tabBarItem.tag == 2 else { return }
+
+        switch tab3Mode {
+        case .changeAutoLayout:
+            /* Good solution: Manipulate top constraint */
+            assert(consoleVC.textViewTopConstraint != nil)
+            if vc.surfaceView.frame.minY + threeLayout.topPadding < vc.layoutInsets.top {
+                consoleVC.textViewTopConstraint?.constant = vc.layoutInsets.top - vc.surfaceView.frame.minY
+            } else {
+                consoleVC.textViewTopConstraint?.constant = threeLayout.topPadding
+            }
+        case .changeOffset:
+            /*
+             Bad solution: Manipulate scroll content inset
+
+             FloatingPanelController keeps a content offset in moving a panel
+             so that changing content inset or offset causes a buggy behavior.
+             */
+            guard let scrollView = consoleVC.textView else { return }
+            var insets = vc.adjustedContentInsets
+            if vc.surfaceView.frame.minY < vc.layoutInsets.top {
+                insets.top = vc.layoutInsets.top - vc.surfaceView.frame.minY
+            } else {
+                insets.top = 0.0
+            }
+            scrollView.contentInset = insets
+
+            if vc.surfaceView.frame.minY > 0 {
+                scrollView.contentOffset = CGPoint(x: 0.0,
+                                                   y: 0.0 - scrollView.contentInset.top)
+            }
+        }
+
+        if vc.surfaceView.frame.minY > vc.originYOfSurface(for: .half) {
+            let progress = (vc.surfaceView.frame.minY - vc.originYOfSurface(for: .half)) / (vc.originYOfSurface(for: .tip) - vc.originYOfSurface(for: .half))
+            threeLayout.leftConstraint.constant = max(min(progress, 1.0), 0.0) * threeLayout.sideMargin
+            threeLayout.rightConstraint.constant = -max(min(progress, 1.0), 0.0) * threeLayout.sideMargin
+        } else {
+            threeLayout.leftConstraint.constant = 0.0
+            threeLayout.rightConstraint.constant = 0.0
+        }
+
+        vc.view.layoutIfNeeded() // MUST
+    }
+
+    func floatingPanelDidChangePosition(_ vc: FloatingPanelController) {
+        guard self.tabBarItem.tag == 2 else { return }
+
+        switch tab3Mode {
+        case .changeAutoLayout:
+            /* Good Solution: Manipulate top constraint */
+            assert(consoleVC.textViewTopConstraint != nil)
+            consoleVC.textViewTopConstraint?.constant = (vc.position == .full) ? vc.layoutInsets.top : 17.0
+
+        case .changeOffset:
+            /* Bad Solution: Manipulate scroll content inset */
+            guard let scrollView = consoleVC.textView else { return }
+            var insets = vc.adjustedContentInsets
+            insets.top = (vc.position == .full) ? vc.layoutInsets.top : 0.0
+            scrollView.contentInset = insets
+            if scrollView.contentOffset.y - scrollView.contentInset.top < 0.0  {
+                scrollView.contentOffset = CGPoint(x: 0.0,
+                                                   y: 0.0 - scrollView.contentInset.top)
+            }
+        }
+
+        if vc.position == .tip {
+            threeLayout.leftConstraint.constant = threeLayout.sideMargin
+            threeLayout.rightConstraint.constant = -threeLayout.sideMargin
+        } else {
+            threeLayout.leftConstraint.constant = 0.0
+            threeLayout.rightConstraint.constant = 0.0
+        }
+        // Can call it, but it's not necessary because it will be also called
+        // by FloatingPanelController after the delegate method
+        vc.view.layoutIfNeeded()
     }
 }
 
@@ -653,22 +1082,107 @@ class OneTabBarPanelLayout: FloatingPanelLayout {
     }
 }
 
-class TwoTabBarPanel2Layout: FloatingPanelLayout {
+class TwoTabBarPanelLayout: FloatingPanelLayout {
     var initialPosition: FloatingPanelPosition {
         return .half
     }
     var supportedPositions: Set<FloatingPanelPosition> {
         return [.full, .half]
     }
+    var topInteractionBuffer: CGFloat {
+        return 100.0
+    }
     var bottomInteractionBuffer: CGFloat {
         return 261.0 - 22.0
     }
 
     func insetFor(position: FloatingPanelPosition) -> CGFloat? {
         switch position {
-        case .full: return 16.0
+        case .full: return 100.0
         case .half: return 261.0
         default: return nil
         }
     }
 }
+
+class TwoTabBarPanelBehavior: FloatingPanelBehavior {
+    func allowsRubberBanding(for edge: UIRectEdge) -> Bool {
+        return (edge == .bottom || edge == .top)
+    }
+}
+
+
+class ThreeTabBarPanelLayout: FloatingPanelFullScreenLayout {
+    weak var parentVC: UIViewController!
+
+    var leftConstraint: NSLayoutConstraint!
+    var rightConstraint: NSLayoutConstraint!
+
+    let topPadding: CGFloat = 17.0
+    let sideMargin: CGFloat = 16.0
+
+    init(parent: UIViewController) {
+        parentVC = parent
+    }
+
+    var bottomInteractionBuffer: CGFloat = 44.0
+
+    var initialPosition: FloatingPanelPosition {
+        return .half
+    }
+    var supportedPositions: Set<FloatingPanelPosition> {
+        return [.full, .half, .tip]
+    }
+    func insetFor(position: FloatingPanelPosition) -> CGFloat? {
+        switch position {
+        case .full: return 0.0
+        case .half: return 261.0 + parentVC.layoutInsets.bottom
+        case .tip: return 88.0 + parentVC.layoutInsets.bottom
+        default: return nil
+        }
+    }
+    func backdropAlphaFor(position: FloatingPanelPosition) -> CGFloat {
+        return 0.3
+    }
+    func prepareLayout(surfaceView: UIView, in view: UIView) -> [NSLayoutConstraint] {
+        if #available(iOS 11.0, *) {
+            leftConstraint = surfaceView.leftAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leftAnchor, constant: 0.0)
+            rightConstraint = surfaceView.rightAnchor.constraint(equalTo: view.safeAreaLayoutGuide.rightAnchor, constant: 0.0)
+        } else {
+            leftConstraint = surfaceView.leftAnchor.constraint(equalTo: view.leftAnchor, constant: 0.0)
+            rightConstraint = surfaceView.rightAnchor.constraint(equalTo: view.rightAnchor, constant: 0.0)
+        }
+        return [ leftConstraint, rightConstraint ]
+    }
+}
+
+class SettingsViewController: InspectableViewController {
+    @IBOutlet weak var largeTitlesSwicth: UISwitch!
+    @IBOutlet weak var translucentSwicth: UISwitch!
+    @IBOutlet weak var versionLabel: UILabel!
+
+    override func viewDidLoad() {
+        versionLabel.text = "Version: \(Bundle.main.infoDictionary?["CFBundleVersion"] ?? "--")"
+    }
+
+    override func viewDidLayoutSubviews() {
+        super.viewDidLayoutSubviews()
+        if #available(iOS 11.0, *) {
+            let prefersLargeTitles = navigationController!.navigationBar.prefersLargeTitles
+            largeTitlesSwicth.setOn(prefersLargeTitles, animated: false)
+        } else {
+            largeTitlesSwicth.isEnabled = false
+        }
+        let isTranslucent = navigationController!.navigationBar.isTranslucent
+        translucentSwicth.setOn(isTranslucent, animated: false)
+    }
+
+    @IBAction func toggleLargeTitle(_ sender: UISwitch) {
+        if #available(iOS 11.0, *) {
+            navigationController?.navigationBar.prefersLargeTitles = sender.isOn
+        }
+    }
+    @IBAction func toggleTranslucent(_ sender: UISwitch) {
+        navigationController?.navigationBar.isTranslucent = sender.isOn
+    }
+}

Examples/Stocks/Stocks.xcodeproj/project.pbxproj

@@ -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;

FloatingPanel.podspec

@@ -1,7 +1,7 @@
 Pod::Spec.new do |s|
 
   s.name                = "FloatingPanel"
-  s.version             = "1.3.0"
+  s.version             = "1.6.4"
   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.
@@ -13,8 +13,7 @@ The new interface displays the related contents and utilities in parallel as a u
   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.swift_version       = "4.0"
 
   s.framework           = "UIKit"
 

Framework/FloatingPanel.xcodeproj/project.pbxproj

@@ -7,20 +7,27 @@
 	objects = {
 
 /* Begin PBXBuildFile section */
-		54352E9821A521CA00CBCA08 /* FloatingPanelView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54352E9721A521CA00CBCA08 /* FloatingPanelView.swift */; };
+		542753C622C49A6E00D17955 /* FloatingPanelLayoutTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 542753C522C49A6E00D17955 /* FloatingPanelLayoutTests.swift */; };
+		542753C822C49A8F00D17955 /* Utils.swift in Sources */ = {isa = PBXBuildFile; fileRef = 542753C722C49A8F00D17955 /* Utils.swift */; };
 		54352E9621A51A2500CBCA08 /* FloatingPanelTransitioning.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54352E9521A51A2500CBCA08 /* FloatingPanelTransitioning.swift */; };
+		54352E9821A521CA00CBCA08 /* FloatingPanelView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54352E9721A521CA00CBCA08 /* FloatingPanelView.swift */; };
 		5450EEE421646DF500135936 /* FloatingPanelBehavior.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5450EEE321646DF500135936 /* FloatingPanelBehavior.swift */; };
 		545DB9CB2151169500CA77B8 /* FloatingPanel.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 545DB9C12151169500CA77B8 /* FloatingPanel.framework */; };
-		545DB9D02151169500CA77B8 /* ViewTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 545DB9CF2151169500CA77B8 /* ViewTests.swift */; };
-		545DB9D22151169500CA77B8 /* FloatingPanelController.h in Headers */ = {isa = PBXBuildFile; fileRef = 545DB9C42151169500CA77B8 /* FloatingPanelController.h */; settings = {ATTRIBUTES = (Public, ); }; };
+		545DB9D02151169500CA77B8 /* FloatingPanelControllerTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 545DB9CF2151169500CA77B8 /* FloatingPanelControllerTests.swift */; };
+		545DB9D22151169500CA77B8 /* FloatingPanel.h in Headers */ = {isa = PBXBuildFile; fileRef = 545DB9C42151169500CA77B8 /* FloatingPanel.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		545DB9DE215118C800CA77B8 /* UIExtensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 545DB9DD215118C800CA77B8 /* UIExtensions.swift */; };
 		545DB9E021511AC100CA77B8 /* FloatingPanelController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 545DB9DF21511AC100CA77B8 /* FloatingPanelController.swift */; };
 		545DBA2B2152383100CA77B8 /* GrabberHandleView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 545DBA2A2152383100CA77B8 /* GrabberHandleView.swift */; };
+		549E944522CF295D0050AECF /* FloatingPanelPositionTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 549E944422CF295D0050AECF /* FloatingPanelPositionTests.swift */; };
+		54A6B6B122968B530077F348 /* FloatingPanelTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54A6B6B022968B530077F348 /* FloatingPanelTests.swift */; };
+		54A6B6B622968F710077F348 /* LaunchScreen.storyboard in Resources */ = {isa = PBXBuildFile; fileRef = 54A6B6B522968F710077F348 /* LaunchScreen.storyboard */; };
+		54A6B6B82296A8520077F348 /* FloatingPanelSurfaceViewTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54A6B6B72296A8520077F348 /* FloatingPanelSurfaceViewTests.swift */; };
 		54ABD7AF216CCFF7002E6C13 /* Logger.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54ABD7AE216CCFF7002E6C13 /* Logger.swift */; };
 		54CDC5D3215B6D5A007D205C /* FloatingPanelSurfaceView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54CDC5D2215B6D5A007D205C /* FloatingPanelSurfaceView.swift */; };
 		54CDC5D5215B6D8D007D205C /* FloatingPanelBackdropView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54CDC5D4215B6D8D007D205C /* FloatingPanelBackdropView.swift */; };
 		54CFBFC3215CD045006B5735 /* FloatingPanelLayout.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54CFBFC2215CD045006B5735 /* FloatingPanelLayout.swift */; };
 		54CFBFC5215CD09C006B5735 /* FloatingPanel.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54CFBFC4215CD09C006B5735 /* FloatingPanel.swift */; };
+		54E740CD218AFD67005C1A34 /* AppDelegate.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54E740CC218AFD67005C1A34 /* AppDelegate.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXContainerItemProxy section */
@@ -31,26 +38,42 @@
 			remoteGlobalIDString = 545DB9C02151169500CA77B8;
 			remoteInfo = FloatingModalController;
 		};
+		54E740DC218AFE9F005C1A34 /* PBXContainerItemProxy */ = {
+			isa = PBXContainerItemProxy;
+			containerPortal = 545DB9B82151169500CA77B8 /* Project object */;
+			proxyType = 1;
+			remoteGlobalIDString = 54E740C9218AFD67005C1A34;
+			remoteInfo = TestingHost;
+		};
 /* End PBXContainerItemProxy section */
 
 /* Begin PBXFileReference section */
-		54352E9721A521CA00CBCA08 /* FloatingPanelView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FloatingPanelView.swift; sourceTree = "<group>"; };
+		542753C522C49A6E00D17955 /* FloatingPanelLayoutTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FloatingPanelLayoutTests.swift; sourceTree = "<group>"; };
+		542753C722C49A8F00D17955 /* Utils.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Utils.swift; sourceTree = "<group>"; };
 		54352E9521A51A2500CBCA08 /* FloatingPanelTransitioning.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FloatingPanelTransitioning.swift; sourceTree = "<group>"; };
+		54352E9721A521CA00CBCA08 /* FloatingPanelView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FloatingPanelView.swift; sourceTree = "<group>"; };
 		5450EEE321646DF500135936 /* FloatingPanelBehavior.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FloatingPanelBehavior.swift; sourceTree = "<group>"; };
 		545DB9C12151169500CA77B8 /* FloatingPanel.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = FloatingPanel.framework; sourceTree = BUILT_PRODUCTS_DIR; };
-		545DB9C42151169500CA77B8 /* FloatingPanelController.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = FloatingPanelController.h; sourceTree = "<group>"; };
+		545DB9C42151169500CA77B8 /* FloatingPanel.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = FloatingPanel.h; sourceTree = "<group>"; };
 		545DB9C52151169500CA77B8 /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
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-		545DB9CF2151169500CA77B8 /* ViewTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ViewTests.swift; sourceTree = "<group>"; };
+		545DB9CF2151169500CA77B8 /* FloatingPanelControllerTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FloatingPanelControllerTests.swift; sourceTree = "<group>"; };
 		545DB9D12151169500CA77B8 /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
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 		545DBA2A2152383100CA77B8 /* GrabberHandleView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = GrabberHandleView.swift; sourceTree = "<group>"; };
+		549E944422CF295D0050AECF /* FloatingPanelPositionTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FloatingPanelPositionTests.swift; sourceTree = "<group>"; };
+		54A6B6B022968B530077F348 /* FloatingPanelTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FloatingPanelTests.swift; sourceTree = "<group>"; };
+		54A6B6B522968F710077F348 /* LaunchScreen.storyboard */ = {isa = PBXFileReference; lastKnownFileType = file.storyboard; path = LaunchScreen.storyboard; sourceTree = "<group>"; };
+		54A6B6B72296A8520077F348 /* FloatingPanelSurfaceViewTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FloatingPanelSurfaceViewTests.swift; sourceTree = "<group>"; };
 		54ABD7AE216CCFF7002E6C13 /* Logger.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Logger.swift; sourceTree = "<group>"; };
 		54CDC5D2215B6D5A007D205C /* FloatingPanelSurfaceView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FloatingPanelSurfaceView.swift; sourceTree = "<group>"; };
 		54CDC5D4215B6D8D007D205C /* FloatingPanelBackdropView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FloatingPanelBackdropView.swift; sourceTree = "<group>"; };
 		54CFBFC2215CD045006B5735 /* FloatingPanelLayout.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FloatingPanelLayout.swift; sourceTree = "<group>"; };
 		54CFBFC4215CD09C006B5735 /* FloatingPanel.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FloatingPanel.swift; sourceTree = "<group>"; };
+		54E740CA218AFD67005C1A34 /* FloatingPanelTesting.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = FloatingPanelTesting.app; sourceTree = BUILT_PRODUCTS_DIR; };
+		54E740CC218AFD67005C1A34 /* AppDelegate.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AppDelegate.swift; sourceTree = "<group>"; };
+		54E740D8218AFD6A005C1A34 /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -69,6 +92,13 @@
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
+		54E740C7218AFD67005C1A34 /* Frameworks */ = {
+			isa = PBXFrameworksBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
 /* End PBXFrameworksBuildPhase section */
 
 /* Begin PBXGroup section */
@@ -77,6 +107,7 @@
 			children = (
 				545DB9C32151169500CA77B8 /* Sources */,
 				545DB9CE2151169500CA77B8 /* Tests */,
+				54E740CB218AFD67005C1A34 /* TestingApp */,
 				545DB9C22151169500CA77B8 /* Products */,
 			);
 			sourceTree = "<group>";
@@ -86,6 +117,7 @@
 			children = (
 				545DB9C12151169500CA77B8 /* FloatingPanel.framework */,
 				545DB9CA2151169500CA77B8 /* FloatingPanelTests.xctest */,
+				54E740CA218AFD67005C1A34 /* FloatingPanelTesting.app */,
 			);
 			name = Products;
 			sourceTree = "<group>";
@@ -94,7 +126,7 @@
 			isa = PBXGroup;
 			children = (
 				545DB9C52151169500CA77B8 /* Info.plist */,
-				545DB9C42151169500CA77B8 /* FloatingPanelController.h */,
+				545DB9C42151169500CA77B8 /* FloatingPanel.h */,
 				545DB9DF21511AC100CA77B8 /* FloatingPanelController.swift */,
 				54352E9521A51A2500CBCA08 /* FloatingPanelTransitioning.swift */,
 				54CFBFC4215CD09C006B5735 /* FloatingPanel.swift */,
@@ -113,12 +145,27 @@
 		545DB9CE2151169500CA77B8 /* Tests */ = {
 			isa = PBXGroup;
 			children = (
-				545DB9CF2151169500CA77B8 /* ViewTests.swift */,
+				54A6B6B022968B530077F348 /* FloatingPanelTests.swift */,
+				545DB9CF2151169500CA77B8 /* FloatingPanelControllerTests.swift */,
+				542753C522C49A6E00D17955 /* FloatingPanelLayoutTests.swift */,
+				54A6B6B72296A8520077F348 /* FloatingPanelSurfaceViewTests.swift */,
+				549E944422CF295D0050AECF /* FloatingPanelPositionTests.swift */,
+				542753C722C49A8F00D17955 /* Utils.swift */,
 				545DB9D12151169500CA77B8 /* Info.plist */,
 			);
 			path = Tests;
 			sourceTree = "<group>";
 		};
+		54E740CB218AFD67005C1A34 /* TestingApp */ = {
+			isa = PBXGroup;
+			children = (
+				54E740CC218AFD67005C1A34 /* AppDelegate.swift */,
+				54E740D8218AFD6A005C1A34 /* Info.plist */,
+				54A6B6B522968F710077F348 /* LaunchScreen.storyboard */,
+			);
+			path = TestingApp;
+			sourceTree = "<group>";
+		};
 /* End PBXGroup section */
 
 /* Begin PBXHeadersBuildPhase section */
@@ -126,7 +173,7 @@
 			isa = PBXHeadersBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
-				545DB9D22151169500CA77B8 /* FloatingPanelController.h in Headers */,
+				545DB9D22151169500CA77B8 /* FloatingPanel.h in Headers */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -163,19 +210,37 @@
 			);
 			dependencies = (
 				545DB9CD2151169500CA77B8 /* PBXTargetDependency */,
+				54E740DD218AFE9F005C1A34 /* PBXTargetDependency */,
 			);
 			name = FloatingPanelTests;
 			productName = FloatingModalControllerTests;
 			productReference = 545DB9CA2151169500CA77B8 /* FloatingPanelTests.xctest */;
 			productType = "com.apple.product-type.bundle.unit-test";
 		};
+		54E740C9218AFD67005C1A34 /* TestingApp */ = {
+			isa = PBXNativeTarget;
+			buildConfigurationList = 54E740D9218AFD6A005C1A34 /* Build configuration list for PBXNativeTarget "TestingApp" */;
+			buildPhases = (
+				54E740C6218AFD67005C1A34 /* Sources */,
+				54E740C7218AFD67005C1A34 /* Frameworks */,
+				54E740C8218AFD67005C1A34 /* Resources */,
+			);
+			buildRules = (
+			);
+			dependencies = (
+			);
+			name = TestingApp;
+			productName = TestingHost;
+			productReference = 54E740CA218AFD67005C1A34 /* FloatingPanelTesting.app */;
+			productType = "com.apple.product-type.application";
+		};
 /* End PBXNativeTarget section */
 
 /* Begin PBXProject section */
 		545DB9B82151169500CA77B8 /* Project object */ = {
 			isa = PBXProject;
 			attributes = {
-				LastSwiftUpdateCheck = 1000;
+				LastSwiftUpdateCheck = 1010;
 				LastUpgradeCheck = 1000;
 				ORGANIZATIONNAME = scenee;
 				TargetAttributes = {
@@ -185,6 +250,10 @@
 					};
 					545DB9C92151169500CA77B8 = {
 						CreatedOnToolsVersion = 10.0;
+						TestTargetID = 54E740C9218AFD67005C1A34;
+					};
+					54E740C9218AFD67005C1A34 = {
+						CreatedOnToolsVersion = 10.1;
 					};
 				};
 			};
@@ -194,6 +263,7 @@
 			hasScannedForEncodings = 0;
 			knownRegions = (
 				en,
+				Base,
 			);
 			mainGroup = 545DB9B72151169500CA77B8;
 			productRefGroup = 545DB9C22151169500CA77B8 /* Products */;
@@ -202,6 +272,7 @@
 			targets = (
 				545DB9C02151169500CA77B8 /* FloatingPanel */,
 				545DB9C92151169500CA77B8 /* FloatingPanelTests */,
+				54E740C9218AFD67005C1A34 /* TestingApp */,
 			);
 		};
 /* End PBXProject section */
@@ -221,6 +292,14 @@
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
+		54E740C8218AFD67005C1A34 /* Resources */ = {
+			isa = PBXResourcesBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+				54A6B6B622968F710077F348 /* LaunchScreen.storyboard in Resources */,
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
 /* End PBXResourcesBuildPhase section */
 
 /* Begin PBXSourcesBuildPhase section */
@@ -239,6 +318,7 @@
 				545DBA2B2152383100CA77B8 /* GrabberHandleView.swift in Sources */,
 				54352E9621A51A2500CBCA08 /* FloatingPanelTransitioning.swift in Sources */,
 				545DB9DE215118C800CA77B8 /* UIExtensions.swift in Sources */,
+				542753C822C49A8F00D17955 /* Utils.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -246,7 +326,19 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
-				545DB9D02151169500CA77B8 /* ViewTests.swift in Sources */,
+				54A6B6B122968B530077F348 /* FloatingPanelTests.swift in Sources */,
+				545DB9D02151169500CA77B8 /* FloatingPanelControllerTests.swift in Sources */,
+				549E944522CF295D0050AECF /* FloatingPanelPositionTests.swift in Sources */,
+				542753C622C49A6E00D17955 /* FloatingPanelLayoutTests.swift in Sources */,
+				54A6B6B82296A8520077F348 /* FloatingPanelSurfaceViewTests.swift in Sources */,
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
+		54E740C6218AFD67005C1A34 /* Sources */ = {
+			isa = PBXSourcesBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+				54E740CD218AFD67005C1A34 /* AppDelegate.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -258,6 +350,11 @@
 			target = 545DB9C02151169500CA77B8 /* FloatingPanel */;
 			targetProxy = 545DB9CC2151169500CA77B8 /* PBXContainerItemProxy */;
 		};
+		54E740DD218AFE9F005C1A34 /* PBXTargetDependency */ = {
+			isa = PBXTargetDependency;
+			target = 54E740C9218AFD67005C1A34 /* TestingApp */;
+			targetProxy = 54E740DC218AFE9F005C1A34 /* PBXContainerItemProxy */;
+		};
 /* End PBXTargetDependency section */
 
 /* Begin XCBuildConfiguration section */
@@ -386,6 +483,7 @@
 		545DB9D62151169500CA77B8 /* Debug */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				APPLICATION_EXTENSION_API_ONLY = YES;
 				CLANG_ENABLE_MODULES = YES;
 				CODE_SIGN_IDENTITY = "";
 				CODE_SIGN_STYLE = Automatic;
@@ -405,8 +503,9 @@
 				PRODUCT_NAME = "$(TARGET_NAME:c99extidentifier)";
 				SKIP_INSTALL = YES;
 				SWIFT_ACTIVE_COMPILATION_CONDITIONS = DEBUG;
+				SWIFT_COMPILATION_MODE = wholemodule;
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
-				SWIFT_VERSION = 4.2;
+				SWIFT_VERSION = 4.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 			};
 			name = Debug;
@@ -414,6 +513,7 @@
 		545DB9D72151169500CA77B8 /* Release */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				APPLICATION_EXTENSION_API_ONLY = YES;
 				CLANG_ENABLE_MODULES = YES;
 				CODE_SIGN_IDENTITY = "";
 				CODE_SIGN_STYLE = Automatic;
@@ -432,7 +532,8 @@
 				PRODUCT_BUNDLE_IDENTIFIER = com.scenee.FloatingPanel;
 				PRODUCT_NAME = "$(TARGET_NAME:c99extidentifier)";
 				SKIP_INSTALL = YES;
-				SWIFT_VERSION = 4.2;
+				SWIFT_COMPILATION_MODE = wholemodule;
+				SWIFT_VERSION = 4.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 			};
 			name = Release;
@@ -442,7 +543,9 @@
 			buildSettings = {
 				ALWAYS_EMBED_SWIFT_STANDARD_LIBRARIES = YES;
 				CODE_SIGN_STYLE = Automatic;
+				DEVELOPMENT_TEAM = "";
 				INFOPLIST_FILE = Tests/Info.plist;
+				IPHONEOS_DEPLOYMENT_TARGET = 10.0;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/Frameworks",
@@ -450,8 +553,9 @@
 				);
 				PRODUCT_BUNDLE_IDENTIFIER = com.scenee.FloatingModalControllerTests;
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 4.2;
+				SWIFT_VERSION = 5.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
+				TEST_HOST = "$(BUILT_PRODUCTS_DIR)/FloatingPanelTesting.app/FloatingPanelTesting";
 			};
 			name = Debug;
 		};
@@ -460,7 +564,9 @@
 			buildSettings = {
 				ALWAYS_EMBED_SWIFT_STANDARD_LIBRARIES = YES;
 				CODE_SIGN_STYLE = Automatic;
+				DEVELOPMENT_TEAM = "";
 				INFOPLIST_FILE = Tests/Info.plist;
+				IPHONEOS_DEPLOYMENT_TARGET = 10.0;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/Frameworks",
@@ -468,11 +574,177 @@
 				);
 				PRODUCT_BUNDLE_IDENTIFIER = com.scenee.FloatingModalControllerTests;
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 4.2;
+				SWIFT_VERSION = 5.0;
+				TARGETED_DEVICE_FAMILY = "1,2";
+				TEST_HOST = "$(BUILT_PRODUCTS_DIR)/FloatingPanelTesting.app/FloatingPanelTesting";
+			};
+			name = Release;
+		};
+		54E740DA218AFD6A005C1A34 /* Debug */ = {
+			isa = XCBuildConfiguration;
+			buildSettings = {
+				CODE_SIGN_STYLE = Automatic;
+				DEVELOPMENT_TEAM = "";
+				INFOPLIST_FILE = TestingApp/Info.plist;
+				IPHONEOS_DEPLOYMENT_TARGET = 10.0;
+				LD_RUNPATH_SEARCH_PATHS = (
+					"$(inherited)",
+					"@executable_path/Frameworks",
+				);
+				PRODUCT_BUNDLE_IDENTIFIER = com.scenee.FloatingPanelTesting;
+				PRODUCT_NAME = FloatingPanelTesting;
+				SWIFT_VERSION = 5.0;
+				TARGETED_DEVICE_FAMILY = "1,2";
+			};
+			name = Debug;
+		};
+		54E740DB218AFD6A005C1A34 /* Release */ = {
+			isa = XCBuildConfiguration;
+			buildSettings = {
+				CODE_SIGN_STYLE = Automatic;
+				DEVELOPMENT_TEAM = "";
+				INFOPLIST_FILE = TestingApp/Info.plist;
+				IPHONEOS_DEPLOYMENT_TARGET = 10.0;
+				LD_RUNPATH_SEARCH_PATHS = (
+					"$(inherited)",
+					"@executable_path/Frameworks",
+				);
+				PRODUCT_BUNDLE_IDENTIFIER = com.scenee.FloatingPanelTesting;
+				PRODUCT_NAME = FloatingPanelTesting;
+				SWIFT_VERSION = 5.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 			};
 			name = Release;
 		};
+		54E79ADF224F6C9800717BC6 /* Test */ = {
+			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;
+				CURRENT_PROJECT_VERSION = 1;
+				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",
+					"$(inherited)",
+				);
+				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
+				GCC_WARN_ABOUT_RETURN_TYPE = YES_ERROR;
+				GCC_WARN_UNDECLARED_SELECTOR = YES;
+				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
+				GCC_WARN_UNUSED_FUNCTION = YES;
+				GCC_WARN_UNUSED_VARIABLE = YES;
+				IPHONEOS_DEPLOYMENT_TARGET = 12.0;
+				MTL_ENABLE_DEBUG_INFO = INCLUDE_SOURCE;
+				MTL_FAST_MATH = YES;
+				ONLY_ACTIVE_ARCH = YES;
+				SDKROOT = iphoneos;
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+				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
+				VERSIONING_SYSTEM = "apple-generic";
+				VERSION_INFO_PREFIX = "";
+			};
+			name = Test;
+		};
+		54E79AE0224F6C9800717BC6 /* Test */ = {
+			isa = XCBuildConfiguration;
+			buildSettings = {
+				APPLICATION_EXTENSION_API_ONLY = YES;
+				CLANG_ENABLE_MODULES = YES;
+				CODE_SIGN_IDENTITY = "";
+				CODE_SIGN_STYLE = Automatic;
+				DEFINES_MODULE = YES;
+				DYLIB_COMPATIBILITY_VERSION = 1;
+				DYLIB_CURRENT_VERSION = 1;
+				DYLIB_INSTALL_NAME_BASE = "@rpath";
+				INFOPLIST_FILE = Sources/Info.plist;
+				INSTALL_PATH = "$(LOCAL_LIBRARY_DIR)/Frameworks";
+				IPHONEOS_DEPLOYMENT_TARGET = 10.0;
+				LD_RUNPATH_SEARCH_PATHS = (
+					"$(inherited)",
+					"@executable_path/Frameworks",
+					"@loader_path/Frameworks",
+				);
+				PRODUCT_BUNDLE_IDENTIFIER = com.scenee.FloatingPanel;
+				PRODUCT_NAME = "$(TARGET_NAME:c99extidentifier)";
+				SKIP_INSTALL = YES;
+				SWIFT_ACTIVE_COMPILATION_CONDITIONS = "DEBUG __FP_LOG";
+				SWIFT_COMPILATION_MODE = wholemodule;
+				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
+				SWIFT_VERSION = 4.0;
+				TARGETED_DEVICE_FAMILY = "1,2";
+			};
+			name = Test;
+		};
+		54E79AE1224F6C9800717BC6 /* Test */ = {
+			isa = XCBuildConfiguration;
+			buildSettings = {
+				ALWAYS_EMBED_SWIFT_STANDARD_LIBRARIES = YES;
+				CODE_SIGN_STYLE = Automatic;
+				DEVELOPMENT_TEAM = "";
+				INFOPLIST_FILE = Tests/Info.plist;
+				IPHONEOS_DEPLOYMENT_TARGET = 10.0;
+				LD_RUNPATH_SEARCH_PATHS = (
+					"$(inherited)",
+					"@executable_path/Frameworks",
+					"@loader_path/Frameworks",
+				);
+				PRODUCT_BUNDLE_IDENTIFIER = com.scenee.FloatingModalControllerTests;
+				PRODUCT_NAME = "$(TARGET_NAME)";
+				SWIFT_VERSION = 5.0;
+				TARGETED_DEVICE_FAMILY = "1,2";
+				TEST_HOST = "$(BUILT_PRODUCTS_DIR)/FloatingPanelTesting.app/FloatingPanelTesting";
+			};
+			name = Test;
+		};
+		54E8AC6A2286CFB6000C5A12 /* Test */ = {
+			isa = XCBuildConfiguration;
+			buildSettings = {
+				DEVELOPMENT_TEAM = "";
+				INFOPLIST_FILE = TestingApp/Info.plist;
+				IPHONEOS_DEPLOYMENT_TARGET = 10.0;
+				LD_RUNPATH_SEARCH_PATHS = "@executable_path/Frameworks";
+				PRODUCT_BUNDLE_IDENTIFIER = com.scenee.FloatingPanelTesting;
+				PRODUCT_NAME = FloatingPanelTesting;
+				SWIFT_VERSION = 5.0;
+				TARGETED_DEVICE_FAMILY = "1,2";
+			};
+			name = Test;
+		};
 /* End XCBuildConfiguration section */
 
 /* Begin XCConfigurationList section */
@@ -480,6 +752,7 @@
 			isa = XCConfigurationList;
 			buildConfigurations = (
 				545DB9D32151169500CA77B8 /* Debug */,
+				54E79ADF224F6C9800717BC6 /* Test */,
 				545DB9D42151169500CA77B8 /* Release */,
 			);
 			defaultConfigurationIsVisible = 0;
@@ -489,6 +762,7 @@
 			isa = XCConfigurationList;
 			buildConfigurations = (
 				545DB9D62151169500CA77B8 /* Debug */,
+				54E79AE0224F6C9800717BC6 /* Test */,
 				545DB9D72151169500CA77B8 /* Release */,
 			);
 			defaultConfigurationIsVisible = 0;
@@ -498,11 +772,22 @@
 			isa = XCConfigurationList;
 			buildConfigurations = (
 				545DB9D92151169500CA77B8 /* Debug */,
+				54E79AE1224F6C9800717BC6 /* Test */,
 				545DB9DA2151169500CA77B8 /* Release */,
 			);
 			defaultConfigurationIsVisible = 0;
 			defaultConfigurationName = Release;
 		};
+		54E740D9218AFD6A005C1A34 /* Build configuration list for PBXNativeTarget "TestingApp" */ = {
+			isa = XCConfigurationList;
+			buildConfigurations = (
+				54E740DA218AFD6A005C1A34 /* Debug */,
+				54E740DB218AFD6A005C1A34 /* Release */,
+				54E8AC6A2286CFB6000C5A12 /* Test */,
+			);
+			defaultConfigurationIsVisible = 0;
+			defaultConfigurationName = Release;
+		};
 /* End XCConfigurationList section */
 	};
 	rootObject = 545DB9B82151169500CA77B8 /* Project object */;

Framework/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>

Framework/Sources/FloatingPanelBehavior.swift

@@ -6,12 +6,28 @@
 import UIKit
 
 public protocol FloatingPanelBehavior {
-    /// Returns the progress to redirect to the previous position
+    /// Asks the behavior if the floating panel should project a momentum of a user interaction to move the proposed 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.
+    /// 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 `FloatingPanelPosition.tip` or `FloatingPanelPosition.full`.
+    func shouldProjectMomentum(_ fpc: FloatingPanelController, for proposedTargetPosition: FloatingPanelPosition) -> Bool
+
+    /// 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.
+    func momentumProjectionRate(_ fpc: FloatingPanelController) -> CGFloat
+
+    /// 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 position. 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.
+    ///
+    /// - Attention:
+    /// By default, it returns a non-interruptible animator to prevent a propagation of the animation to a content view.
+    /// However returning an interruptible animator is working well depending on a content view and it can be better
+    /// than using a non-interruptible one.
     func interactionAnimator(_ fpc: FloatingPanelController, to targetPosition: FloatingPanelPosition, with velocity: CGVector) -> UIViewPropertyAnimator
 
     /// Returns a UIViewPropertyAnimator object to add a floating panel to a position.
@@ -46,13 +62,35 @@ public protocol FloatingPanelBehavior {
     ///
     /// 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
+
+
+    /// Asks the behavior whether the rubber band effect is enabled in moving over a given edge of the surface view.
+    ///
+    /// This method allows the behavior to activate the rubber band effect to a given edge of the surface view. By default, the effect is disabled.
+    func allowsRubberBanding(for edge: UIRectEdge) -> Bool
 }
 
 public extension FloatingPanelBehavior {
+    func shouldProjectMomentum(_ fpc: FloatingPanelController, for proposedTargetPosition: FloatingPanelPosition) -> Bool {
+        return false
+    }
+
+    func momentumProjectionRate(_ fpc: FloatingPanelController) -> CGFloat {
+        #if swift(>=4.2)
+        return UIScrollView.DecelerationRate.normal.rawValue
+        #else
+        return UIScrollViewDecelerationRateNormal
+        #endif
+    }
+
     func redirectionalProgress(_ fpc: FloatingPanelController, from: FloatingPanelPosition, to: FloatingPanelPosition) -> CGFloat {
         return 0.5
     }
 
+    func interactionAnimator(_ fpc: FloatingPanelController, to targetPosition: FloatingPanelPosition, with velocity: CGVector) -> UIViewPropertyAnimator {
+        return defaultBehavior.interactionAnimator(fpc, to: targetPosition, with: velocity)
+    }
+
     func addAnimator(_ fpc: FloatingPanelController, to: FloatingPanelPosition) -> UIViewPropertyAnimator {
         return UIViewPropertyAnimator(duration: 0.25, curve: .easeInOut)
     }
@@ -80,12 +118,22 @@ public extension FloatingPanelBehavior {
                                         initialVelocity: velocity)
         return UIViewPropertyAnimator(duration: 0, timingParameters: timing)
     }
+
+    func allowsRubberBanding(for edge: UIRectEdge) -> Bool {
+        return false
+    }
 }
 
-class FloatingPanelDefaultBehavior: FloatingPanelBehavior {
-    func interactionAnimator(_ fpc: FloatingPanelController, to targetPosition: FloatingPanelPosition, with velocity: CGVector) -> UIViewPropertyAnimator {
+private let defaultBehavior = FloatingPanelDefaultBehavior()
+
+public class FloatingPanelDefaultBehavior: FloatingPanelBehavior {
+    public init() { }
+
+    public func interactionAnimator(_ fpc: FloatingPanelController, to targetPosition: FloatingPanelPosition, with velocity: CGVector) -> UIViewPropertyAnimator {
         let timing = timeingCurve(with: velocity)
-        return UIViewPropertyAnimator(duration: 0, timingParameters: timing)
+        let animator = UIViewPropertyAnimator(duration: 0, timingParameters: timing)
+        animator.isInterruptible = false // Prevent a propagation of the animation(spring etc) to a content view
+        return animator
     }
 
     private func timeingCurve(with velocity: CGVector) -> UITimingCurveProvider {

Framework/Sources/FloatingPanelController.swift

@@ -14,7 +14,10 @@ public protocol FloatingPanelControllerDelegate: class {
 
     func floatingPanelDidChangePosition(_ vc: FloatingPanelController) // changed the settled position in the model layer
 
-    func floatingPanelDidMove(_ vc: FloatingPanelController) // any offset changes
+    /// Asks the delegate if dragging should begin by the pan gesture recognizer.
+    func floatingPanelShouldBeginDragging(_ vc: FloatingPanelController) -> Bool
+
+    func floatingPanelDidMove(_ vc: FloatingPanelController) // any surface frame changes in dragging
 
     // called on start of dragging (may require some time and or distance to move)
     func floatingPanelWillBeginDragging(_ vc: FloatingPanelController)
@@ -27,6 +30,11 @@ public protocol FloatingPanelControllerDelegate: class {
     func floatingPanelDidEndDraggingToRemove(_ vc: FloatingPanelController, withVelocity velocity: CGPoint)
     // called when its views are removed from a parent view controller
     func floatingPanelDidEndRemove(_ vc: FloatingPanelController)
+
+    /// Asks the delegate if the other gesture recognizer should be allowed to recognize the gesture in parallel.
+    ///
+    /// By default, any tap and long gesture recognizers are allowed to recognize gestures simultaneously.
+    func floatingPanel(_ vc: FloatingPanelController, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool
 }
 
 public extension FloatingPanelControllerDelegate {
@@ -37,6 +45,9 @@ public extension FloatingPanelControllerDelegate {
         return nil
     }
     func floatingPanelDidChangePosition(_ vc: FloatingPanelController) {}
+    func floatingPanelShouldBeginDragging(_ vc: FloatingPanelController) -> Bool {
+        return true
+    }
     func floatingPanelDidMove(_ vc: FloatingPanelController) {}
     func floatingPanelWillBeginDragging(_ vc: FloatingPanelController) {}
     func floatingPanelDidEndDragging(_ vc: FloatingPanelController, withVelocity velocity: CGPoint, targetPosition: FloatingPanelPosition) {}
@@ -45,19 +56,58 @@ public extension FloatingPanelControllerDelegate {
 
     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 {
+
+public enum FloatingPanelPosition: Int {
     case full
     case half
     case tip
     case hidden
+
+    static var allCases: [FloatingPanelPosition] {
+        return [.full, .half, .tip, .hidden]
+    }
+
+    func next(in positions: [FloatingPanelPosition]) -> FloatingPanelPosition {
+        #if swift(>=4.2)
+        guard
+            let index = positions.firstIndex(of: self),
+            positions.indices.contains(index + 1)
+            else { return self }
+        #else
+        guard
+            let index = positions.index(of: self),
+            positions.indices.contains(index + 1)
+            else { return self }
+        #endif
+        return positions[index + 1]
+    }
+
+    func pre(in positions: [FloatingPanelPosition]) -> FloatingPanelPosition {
+        #if swift(>=4.2)
+        guard
+            let index = positions.firstIndex(of: self),
+            positions.indices.contains(index - 1)
+            else { return self }
+        #else
+        guard
+            let index = positions.index(of: self),
+            positions.indices.contains(index - 1)
+            else { return self }
+        #endif
+        return positions[index - 1]
+    }
 }
 
 ///
 /// A container view controller to display a floating panel to present contents in parallel as a user wants.
 ///
-public class FloatingPanelController: UIViewController, UIScrollViewDelegate, UIGestureRecognizerDelegate {
+open class FloatingPanelController: UIViewController, UIScrollViewDelegate, UIGestureRecognizerDelegate {
     /// Constants indicating how safe area insets are added to the adjusted content inset.
     public enum ContentInsetAdjustmentBehavior: Int {
         case always
@@ -65,7 +115,11 @@ public class FloatingPanelController: UIViewController, UIScrollViewDelegate, UI
     }
 
     /// The delegate of the floating panel controller object.
-    public weak var delegate: FloatingPanelControllerDelegate?
+    public weak var delegate: FloatingPanelControllerDelegate?{
+        didSet{
+            didUpdateDelegate()
+        }
+    }
 
     /// Returns the surface view managed by the controller object. It's the same as `self.view`.
     public var surfaceView: FloatingPanelSurfaceView! {
@@ -84,7 +138,7 @@ public class FloatingPanelController: UIViewController, UIScrollViewDelegate, UI
 
     // The underlying gesture recognizer for pan gestures
     public var panGestureRecognizer: UIPanGestureRecognizer {
-        return floatingPanel.panGesture
+        return floatingPanel.panGestureRecognizer
     }
 
     /// The current position of the floating panel controller's contents.
@@ -125,18 +179,20 @@ public class FloatingPanelController: UIViewController, UIScrollViewDelegate, UI
     }
     private var _contentViewController: UIViewController?
 
-    private var floatingPanel: FloatingPanel!
+    private(set) var floatingPanel: FloatingPanel!
+    private var preSafeAreaInsets: UIEdgeInsets = .zero // Capture the latest one
     private var safeAreaInsetsObservation: NSKeyValueObservation?
     private let modalTransition = FloatingPanelModalTransition()
 
-    required init?(coder aDecoder: NSCoder) {
+    required public init?(coder aDecoder: NSCoder) {
         super.init(coder: aDecoder)
         setUp()
     }
 
     /// Initialize a newly created floating panel controller.
-    public init() {
+    public init(delegate: FloatingPanelControllerDelegate? = nil) {
         super.init(nibName: nil, bundle: nil)
+        self.delegate = delegate
         setUp()
     }
 
@@ -151,73 +207,69 @@ public class FloatingPanelController: UIViewController, UIScrollViewDelegate, UI
                                       behavior: fetchBehavior(for: self.traitCollection))
     }
 
+    private func didUpdateDelegate(){
+        floatingPanel.layoutAdapter.layout = fetchLayout(for: traitCollection)
+        floatingPanel.behavior = fetchBehavior(for: self.traitCollection)
+    }
+    
     // MARK:- Overrides
 
     /// Creates the view that the controller manages.
-    override public func loadView() {
+    open override 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 viewDidLoad() {
-        super.viewDidLoad()
-        floatingPanel.setUpViews(in: self)
-    }
-
-    public override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
-        super.viewWillTransition(to: size, with: coordinator)
-
-        view.frame.size = size
-        view.layoutIfNeeded()
-
-        floatingPanel.layoutAdapter.checkLayoutConsistance()
-    }
-
-    public override func willTransition(to newCollection: UITraitCollection, with coordinator: UIViewControllerTransitionCoordinator) {
-        super.willTransition(to: newCollection, with: coordinator)
-
-        // Change layout for a new trait collection
-        updateLayout(for: newCollection)
-
-        floatingPanel.behavior = fetchBehavior(for: newCollection)
-    }
-
-    public override func traitCollectionDidChange(_ previousTraitCollection: UITraitCollection?) {
-        super.traitCollectionDidChange(previousTraitCollection)
-        guard previousTraitCollection != traitCollection else { return }
-
-        self.update(safeAreaInsets: layoutInsets)
-    }
-
-    public override func viewDidAppear(_ animated: Bool) {
-        super.viewDidAppear(animated)
-        // Must track safeAreaInsets/{top,bottom}LayoutGuide of the `self.view`
-        // to update floatingPanel.safeAreaInsets`. 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.
-        if #available(iOS 11.0, *) {
-            safeAreaInsetsObservation = self.observe(\.view.safeAreaInsets) { [weak self] (vc, chaneg) in
-                guard let self = self else { return }
-                self.update(safeAreaInsets: vc.layoutInsets)
+    open override func viewDidLayoutSubviews() {
+        super.viewDidLayoutSubviews()
+        if #available(iOS 11.0, *) {}
+        else {
+            // Because {top,bottom}LayoutGuide is managed as a view
+            if preSafeAreaInsets != layoutInsets,
+                floatingPanel.isDecelerating == false {
+                self.update(safeAreaInsets: layoutInsets)
             }
-        } else {
-            // KVOs for topLayoutGuide & bottomLayoutGuide are not effective.
-            // Instead, safeAreaInsets is updated here
-            self.update(safeAreaInsets: layoutInsets)
         }
     }
 
-    public override func viewWillDisappear(_ animated: Bool) {
+    open override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
+        super.viewWillTransition(to: size, with: coordinator)
+
+        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)
+        self.prepare(for: newCollection)
+    }
+
+    open override func viewWillDisappear(_ animated: Bool) {
         super.viewWillDisappear(animated)
         safeAreaInsetsObservation = nil
     }
 
+    // MARK:- Internals
+    func prepare(for newCollection: UITraitCollection) {
+        guard newCollection.shouldUpdateLayout(from: traitCollection) else { return }
+        // Change a layout & behavior for a new trait collection
+        reloadLayout(for: newCollection)
+        activateLayout()
+        floatingPanel.behavior = fetchBehavior(for: newCollection)
+    }
+
     // MARK:- Privates
 
     private func fetchLayout(for traitCollection: UITraitCollection) -> FloatingPanelLayout {
@@ -234,12 +286,16 @@ public class FloatingPanelController: UIViewController, UIScrollViewDelegate, UI
     }
 
     private func update(safeAreaInsets: UIEdgeInsets) {
-        // preserve the current content offset
-        let contentOffset = scrollView?.contentOffset
+        guard
+            preSafeAreaInsets != safeAreaInsets
+            else { return }
 
-        floatingPanel.safeAreaInsets = safeAreaInsets
+        log.debug("Update safeAreaInsets", safeAreaInsets)
 
-        scrollView?.contentOffset = contentOffset ?? .zero
+        // Prevent an infinite loop on iOS 10: setUpLayout() -> viewDidLayoutSubviews() -> setUpLayout()
+        preSafeAreaInsets = safeAreaInsets
+
+        activateLayout()
 
         switch contentInsetAdjustmentBehavior {
         case .always:
@@ -250,10 +306,28 @@ public class FloatingPanelController: UIViewController, UIScrollViewDelegate, UI
         }
     }
 
-    private func updateLayout(for traitCollection: UITraitCollection) {
+    private func reloadLayout(for traitCollection: UITraitCollection) {
         floatingPanel.layoutAdapter.layout = fetchLayout(for: traitCollection)
         floatingPanel.layoutAdapter.prepareLayout(in: self)
+
+        if let parent = self.parent {
+            if let layout = layout 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.")
+            }
+            if let behavior = behavior 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.")
+            }
+        }
+    }
+
+    private func activateLayout() {
+        // 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
@@ -261,7 +335,25 @@ public class FloatingPanelController: UIViewController, UIScrollViewDelegate, UI
     /// 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
-        updateLayout(for: traitCollection)
+        reloadLayout(for: traitCollection)
+        activateLayout()
+
+        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, options: [.initial, .new, .old]) { [weak self] (vc, change) in
+                guard change.oldValue != change.newValue 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)
@@ -269,6 +361,7 @@ public class FloatingPanelController: UIViewController, UIScrollViewDelegate, UI
 
     /// 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)
@@ -296,13 +389,28 @@ public class FloatingPanelController: UIViewController, UIScrollViewDelegate, UI
             parent.view.addSubview(self.view)
         }
 
-        view.frame = parent.view.bounds // MUST
-
+        #if swift(>=4.2)
         parent.addChild(self)
+        #else
+        parent.addChildViewController(self)
+        #endif
 
-        show(animated: true) { [weak self] in
-            guard let self = self else { return }
-            self.didMove(toParent: parent)
+        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 }
+            #if swift(>=4.2)
+            self.didMove(toParent: self)
+            #else
+            self.didMove(toParentViewController: self)
+            #endif
         }
     }
 
@@ -317,10 +425,21 @@ public class FloatingPanelController: UIViewController, UIScrollViewDelegate, UI
         }
 
         hide(animated: animated) { [weak self] in
-            guard let self = self else { return }
+            guard let `self` = self else { return }
+            #if swift(>=4.2)
             self.willMove(toParent: nil)
+            #else
+            self.willMove(toParentViewController: nil)
+            #endif
+
             self.view.removeFromSuperview()
+
+            #if swift(>=4.2)
             self.removeFromParent()
+            #else
+            self.removeFromParentViewController()
+            #endif
+
             completion?()
         }
     }
@@ -335,33 +454,53 @@ public class FloatingPanelController: UIViewController, UIScrollViewDelegate, UI
         floatingPanel.move(to: to, animated: animated, completion: completion)
     }
 
-    /// Sets the view controller responsible for the content portion of the floating panel..
+    /// Sets the view controller responsible for the content portion of the floating panel.
     public func set(contentViewController: UIViewController?) {
         if let vc = _contentViewController {
+            #if swift(>=4.2)
             vc.willMove(toParent: nil)
+            #else
+            vc.willMove(toParentViewController: nil)
+            #endif
+
             vc.view.removeFromSuperview()
+
+            #if swift(>=4.2)
             vc.removeFromParent()
+            #else
+            vc.removeFromParentViewController()
+            #endif
         }
 
         if let vc = contentViewController {
-            let surfaceView = floatingPanel.surfaceView
-            surfaceView.add(childView: vc.view)
+            #if swift(>=4.2)
             addChild(vc)
+            #else
+            addChildViewController(vc)
+            #endif
+
+            let surfaceView = floatingPanel.surfaceView
+            surfaceView.add(contentView: vc.view)
+
+            #if swift(>=4.2)
             vc.didMove(toParent: self)
+            #else
+            vc.didMove(toParentViewController: self)
+            #endif
         }
 
         _contentViewController = contentViewController
     }
-    
+
     @available(*, unavailable, renamed: "set(contentViewController:)")
-    public override func show(_ vc: UIViewController, sender: Any?) {
+    open  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?) {
+    open  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)
         }
@@ -371,23 +510,30 @@ public class FloatingPanelController: UIViewController, UIScrollViewDelegate, UI
 
     /// 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
+    /// - Parameters:
+    ///     - scrollView: Specify a scroll view to continuously and seamlessly work in concert with interactions of the surface view or nil to cancel it.
+    public func track(scrollView: UIScrollView?) {
+        guard let scrollView = scrollView else {
+            floatingPanel.scrollView = nil
+            return
         }
+
+        floatingPanel.scrollView = scrollView
+
         switch contentInsetAdjustmentBehavior {
         case .always:
             if #available(iOS 11.0, *) {
                 scrollView.contentInsetAdjustmentBehavior = .never
             } else {
+                #if swift(>=4.2)
                 children.forEach { (vc) in
                     vc.automaticallyAdjustsScrollViewInsets = false
                 }
+                #else
+                childViewControllers.forEach { (vc) in
+                    vc.automaticallyAdjustsScrollViewInsets = false
+                }
+                #endif
             }
         default:
             break
@@ -404,22 +550,13 @@ public class FloatingPanelController: UIViewController, UIScrollViewDelegate, UI
     /// to update the floating panel's layout immediately. It can be called in an
     /// animation block.
     public func updateLayout() {
-        updateLayout(for: view.traitCollection)
-        floatingPanel.layoutAdapter.checkLayoutConsistance()
+        reloadLayout(for: traitCollection)
+        activateLayout()
     }
 
-    /// Returns the y-coordinate of the point at the origin of the surface view
+    /// 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
-        }
+        return floatingPanel.layoutAdapter.positionY(for: pos)
     }
 }
 
@@ -441,14 +578,30 @@ extension FloatingPanelController {
 }
 
 public extension UIViewController {
-    @objc public func fp_original_dismiss(animated flag: Bool, completion: (() -> Void)? = nil) {
+    @objc 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) {
-        if let fpc = parent as? FloatingPanelController, fpc.parent != nil {
-            fpc.removePanelFromParent(animated: flag, completion: completion)
-        } else {
-            self.fp_original_dismiss(animated: flag, completion: 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 {
+            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

@@ -5,12 +5,21 @@
 
 import UIKit
 
+/// FloatingPanelFullScreenLayout
+///
+/// Use the layout protocol if you configure full, half and tip insets from the superview, not the safe area.
+/// It can't be used with FloatingPanelIntrinsicLayout.
+public protocol FloatingPanelFullScreenLayout: FloatingPanelLayout { }
+
 /// FloatingPanelIntrinsicLayout
 ///
+/// Use the layout protocol if you want to layout a panel using the intrinsic height.
+/// It can't be used with FloatingPanelFullScreenLayout.
+///
 /// - 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.
+///     `insetFor(position:)` must return `nil` for the full position. Because
+///     the inset is determined automatically by the intrinsic height.
+///     You can customize insets only for the half, tip and hidden positions.
 public protocol FloatingPanelIntrinsicLayout: FloatingPanelLayout { }
 
 public extension FloatingPanelIntrinsicLayout {
@@ -34,19 +43,21 @@ public protocol FloatingPanelLayout: class {
     /// 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.
+    /// By default, it returns full, half and tip positions.
     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.
+    ///
+    /// - Important:
+    /// The specified buffer is ignored when `FloatingPanelController.isRemovalInteractionEnabled` is set to true.
     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.
+    /// Its returning value indicates a different inset for each position.
     /// 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`.
@@ -72,7 +83,7 @@ public extension FloatingPanelLayout {
     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),
@@ -86,8 +97,8 @@ public extension FloatingPanelLayout {
 }
 
 public class FloatingPanelDefaultLayout: FloatingPanelLayout {
-    public var contentViewController: UIViewController?
-    
+    public init() { }
+
     public var initialPosition: FloatingPanelPosition {
         return .half
     }
@@ -103,8 +114,8 @@ public class FloatingPanelDefaultLayout: FloatingPanelLayout {
 }
 
 public class FloatingPanelDefaultLandscapeLayout: FloatingPanelLayout {
-    public var contentViewController: UIViewController?
-    
+    public init() { }
+
     public var initialPosition: FloatingPanelPosition {
         return .tip
     }
@@ -121,29 +132,36 @@ public class FloatingPanelDefaultLandscapeLayout: FloatingPanelLayout {
     }
 }
 
+struct LayoutSegment {
+    let lower: FloatingPanelPosition?
+    let upper: FloatingPanelPosition?
+}
 
 class FloatingPanelLayoutAdapter {
-    weak var vc: UIViewController!
+    weak var vc: FloatingPanelController!
     private weak var surfaceView: FloatingPanelSurfaceView!
     private weak var backdropView: FloatingPanelBackdropView!
 
-    var layout: FloatingPanelLayout
-
-    var safeAreaInsets: UIEdgeInsets = .zero {
+    var layout: FloatingPanelLayout {
         didSet {
-            if oldValue != safeAreaInsets {
-                updateHeight()
-            }
+            checkLayoutConsistance()
         }
     }
 
-    private var heightBuffer: CGFloat = 88.0 // For bounce
+    private var safeAreaInsets: UIEdgeInsets {
+        return vc?.layoutInsets ?? .zero
+    }
+
+    private var initialConst: CGFloat = 0.0
+
     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 interactiveTopConstraint: NSLayoutConstraint?
+
+    private var heightConstraint: NSLayoutConstraint?
 
     private var fullInset: CGFloat {
         if layout is FloatingPanelIntrinsicLayout {
@@ -163,46 +181,33 @@ class FloatingPanelLayoutAdapter {
     }
 
     var supportedPositions: Set<FloatingPanelPosition> {
-        var supportedPositions = layout.supportedPositions
-        supportedPositions.remove(.hidden)
-        return supportedPositions
+        return layout.supportedPositions
+    }
+
+    var topMostState: FloatingPanelPosition {
+        return supportedPositions.sorted(by: { $0.rawValue < $1.rawValue }).first ?? .hidden
+    }
+
+    var bottomMostState: FloatingPanelPosition {
+        return supportedPositions.sorted(by: { $0.rawValue < $1.rawValue }).last ?? .hidden
     }
 
     var topY: CGFloat {
-        if supportedPositions.contains(.full) {
-            if layout is FloatingPanelIntrinsicLayout {
-                return surfaceView.superview!.bounds.height - (safeAreaInsets.bottom + fullInset)
-            } else {
-                return (safeAreaInsets.top + fullInset)
-            }
-        } else {
-            return middleY
-        }
-    }
-
-    var middleY: CGFloat {
-        return surfaceView.superview!.bounds.height - (safeAreaInsets.bottom + halfInset)
+        return positionY(for: topMostState)
     }
 
     var bottomY: CGFloat {
-        if supportedPositions.contains(.tip) {
-            return surfaceView.superview!.bounds.height - (safeAreaInsets.bottom + tipInset)
-        } else {
-            return middleY
-        }
+        return positionY(for: bottomMostState)
     }
 
-    var hiddenY: CGFloat {
-        return surfaceView.superview!.bounds.height
+    var topMaxY: CGFloat {
+        return topY - layout.topInteractionBuffer
     }
 
-    var safeAreaBottomY: CGFloat {
-        return surfaceView.superview!.bounds.height - (safeAreaInsets.bottom + hiddenInset)
+    var bottomMaxY: CGFloat {
+        return bottomY + layout.bottomInteractionBuffer
     }
 
-    var topMaxY: CGFloat { return -safeAreaInsets.top }
-    var bottomMaxY: CGFloat { return safeAreaBottomY }
-
     var adjustedContentInsets: UIEdgeInsets {
         return UIEdgeInsets(top: 0.0,
                             left: 0.0,
@@ -213,13 +218,30 @@ class FloatingPanelLayoutAdapter {
     func positionY(for pos: FloatingPanelPosition) -> CGFloat {
         switch pos {
         case .full:
-            return topY
+            switch layout {
+            case is FloatingPanelIntrinsicLayout:
+                return surfaceView.superview!.bounds.height - surfaceView.bounds.height
+            case is FloatingPanelFullScreenLayout:
+                return fullInset
+            default:
+                return (safeAreaInsets.top + fullInset)
+            }
         case .half:
-            return middleY
+            switch layout {
+            case is FloatingPanelFullScreenLayout:
+                return surfaceView.superview!.bounds.height - halfInset
+            default:
+                return surfaceView.superview!.bounds.height - (safeAreaInsets.bottom + halfInset)
+            }
         case .tip:
-            return bottomY
+            switch layout {
+            case is FloatingPanelFullScreenLayout:
+                return surfaceView.superview!.bounds.height - tipInset
+            default:
+                return surfaceView.superview!.bounds.height - (safeAreaInsets.bottom + tipInset)
+            }
         case .hidden:
-            return hiddenY
+            return surfaceView.superview!.bounds.height - hiddenInset
         }
     }
 
@@ -232,18 +254,35 @@ class FloatingPanelLayoutAdapter {
     }
 
     func updateIntrinsicHeight() {
+        #if swift(>=4.2)
         let fittingSize = UIView.layoutFittingCompressedSize
-        intrinsicHeight = surfaceView.contentView.systemLayoutSizeFitting(fittingSize).height
+        #else
+        let fittingSize = UILayoutFittingCompressedSize
+        #endif
+        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) {
+    func prepareLayout(in vc: FloatingPanelController) {
         self.vc = vc
 
+        NSLayoutConstraint.deactivate(fixedConstraints + fullConstraints + halfConstraints + tipConstraints + offConstraints)
+
         surfaceView.translatesAutoresizingMaskIntoConstraints = false
         backdropView.translatesAutoresizingMaskIntoConstraints = false
 
-        NSLayoutConstraint.deactivate(fixedConstraints + fullConstraints + halfConstraints + tipConstraints + offConstraints)
-
         // Fixed constraints of surface and backdrop views
         let surfaceConstraints = layout.prepareLayout(surfaceView: surfaceView, in: vc.view!)
         let backdropConstraints = [
@@ -255,62 +294,99 @@ class FloatingPanelLayoutAdapter {
 
         fixedConstraints = surfaceConstraints + backdropConstraints
 
-        // Flexible surface constarints for full, half, tip and off
-        if layout is FloatingPanelIntrinsicLayout {
-            updateIntrinsicHeight()
+        // Flexible surface constraints for full, half, tip and off
+        let topAnchor: NSLayoutYAxisAnchor = {
+            if layout is FloatingPanelFullScreenLayout {
+                return vc.view.topAnchor
+            } else {
+                return vc.layoutGuide.topAnchor
+            }
+        }()
+
+        switch layout {
+        case is FloatingPanelIntrinsicLayout:
+            // Set up on updateHeight()
+            break
+        default:
             fullConstraints = [
-                surfaceView.topAnchor.constraint(equalTo: vc.layoutGuide.bottomAnchor,
-                                                 constant: -fullInset),
-            ]
-        } else {
-            fullConstraints = [
-                surfaceView.topAnchor.constraint(equalTo: vc.layoutGuide.topAnchor,
+                surfaceView.topAnchor.constraint(equalTo: topAnchor,
                                                  constant: fullInset),
             ]
         }
+
+        let bottomAnchor: NSLayoutYAxisAnchor = {
+            if layout is FloatingPanelFullScreenLayout {
+                return vc.view.bottomAnchor
+            } else {
+                return vc.layoutGuide.bottomAnchor
+            }
+        }()
+
         halfConstraints = [
-            surfaceView.topAnchor.constraint(equalTo: vc.layoutGuide.bottomAnchor,
+            surfaceView.topAnchor.constraint(equalTo: bottomAnchor,
                                              constant: -halfInset),
         ]
         tipConstraints = [
-            surfaceView.topAnchor.constraint(equalTo: vc.layoutGuide.bottomAnchor,
+            surfaceView.topAnchor.constraint(equalTo: bottomAnchor,
                                              constant: -tipInset),
         ]
+
         offConstraints = [
-            surfaceView.topAnchor.constraint(equalTo: vc.view.bottomAnchor,
+            surfaceView.topAnchor.constraint(equalTo:vc.view.bottomAnchor,
                                              constant: -hiddenInset),
         ]
     }
 
+    func startInteraction(at state: FloatingPanelPosition, offset: CGPoint = .zero) {
+        guard self.interactiveTopConstraint == nil else { return }
+        NSLayoutConstraint.deactivate(fullConstraints + halfConstraints + tipConstraints + offConstraints)
+
+        let interactiveTopConstraint: NSLayoutConstraint
+        switch layout {
+        case is FloatingPanelIntrinsicLayout,
+             is FloatingPanelFullScreenLayout:
+            initialConst = surfaceView.frame.minY + offset.y
+            interactiveTopConstraint = surfaceView.topAnchor.constraint(equalTo: vc.view.topAnchor,
+                                                                        constant: initialConst)
+        default:
+            initialConst = surfaceView.frame.minY - safeAreaInsets.top + offset.y
+            interactiveTopConstraint = surfaceView.topAnchor.constraint(equalTo: vc.layoutGuide.topAnchor,
+                                                                        constant: initialConst)
+        }
+        NSLayoutConstraint.activate([interactiveTopConstraint])
+        self.interactiveTopConstraint = interactiveTopConstraint
+    }
+
+    func endInteraction(at state: FloatingPanelPosition) {
+        // Don't deactivate `interactiveTopConstraint` here because it leads to
+        // unsatisfiable constraints
+    }
+
     // 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 }
-        defer {
-            UIView.performWithoutAnimation {
-                surfaceView.superview!.layoutIfNeeded()
-            }
+
+        if let const = self.heightConstraint {
+            NSLayoutConstraint.deactivate([const])
         }
 
-        NSLayoutConstraint.deactivate(heightConstraints)
+        let heightConstraint: NSLayoutConstraint
 
-        let height: CGFloat
-        if layout is FloatingPanelIntrinsicLayout {
+        switch layout {
+        case is FloatingPanelIntrinsicLayout:
             updateIntrinsicHeight()
-            height = intrinsicHeight + safeAreaInsets.bottom
-        } else {
-            // Must use the`vc` height, not the screen height because safe area insets
-            // of `vc` are relative values. For example, a view controller in
-            // Navigation controller's safe area insets and frame can be changed whether
-            // the navigation bar is translucent or not.
-            height = vc.view.bounds.height - (safeAreaInsets.top + fullInset)
+            heightConstraint = surfaceView.heightAnchor.constraint(equalToConstant: intrinsicHeight + safeAreaInsets.bottom)
+        default:
+            let const = -(positionY(for: topMostState))
+            heightConstraint =  surfaceView.heightAnchor.constraint(equalTo: vc.view.heightAnchor,
+                                                                    constant: const)
         }
 
-        heightConstraints = [
-            surfaceView.heightAnchor.constraint(equalToConstant: height)
-        ]
-        NSLayoutConstraint.activate(heightConstraints)
-        surfaceView.set(bottomOverflow: heightBuffer + layout.topInteractionBuffer)
+        NSLayoutConstraint.activate([heightConstraint])
+        self.heightConstraint = heightConstraint
+
+        surfaceView.bottomOverflow = vc.view.bounds.height + layout.topInteractionBuffer
 
         if layout is FloatingPanelIntrinsicLayout {
             NSLayoutConstraint.deactivate(fullConstraints)
@@ -318,43 +394,102 @@ class FloatingPanelLayoutAdapter {
                 surfaceView.topAnchor.constraint(equalTo: vc.layoutGuide.bottomAnchor,
                                                  constant: -fullInset),
             ]
-            NSLayoutConstraint.activate(fullConstraints)
         }
     }
 
+    func updateInteractiveTopConstraint(diff: CGFloat, allowsTopBuffer: Bool, with behavior: FloatingPanelBehavior) {
+        defer {
+            surfaceView.superview!.layoutIfNeeded() // MUST call here to update `surfaceView.frame`
+        }
+
+        let topMostConst: CGFloat = {
+            var ret: CGFloat = 0.0
+            switch layout {
+            case is FloatingPanelIntrinsicLayout, is FloatingPanelFullScreenLayout:
+                ret = topY
+            default:
+                ret = topY - safeAreaInsets.top
+            }
+            return max(ret, 0.0) // The top boundary is equal to the related topAnchor.
+        }()
+        let bottomMostConst: CGFloat = {
+            var ret: CGFloat = 0.0
+            let _bottomY = vc.isRemovalInteractionEnabled ? positionY(for: .hidden) : bottomY
+            switch layout {
+            case is FloatingPanelIntrinsicLayout, is FloatingPanelFullScreenLayout:
+                ret = _bottomY
+            default:
+                ret = _bottomY - safeAreaInsets.top
+            }
+            return min(ret, surfaceView.superview!.bounds.height)
+        }()
+        let minConst = allowsTopBuffer ? topMostConst - layout.topInteractionBuffer : topMostConst
+        let maxConst = bottomMostConst + layout.bottomInteractionBuffer
+
+        var const = initialConst + diff
+
+        // Rubberbanding top buffer
+        if behavior.allowsRubberBanding(for: .top), const < topMostConst {
+            let buffer = topMostConst - const
+            const = topMostConst - rubberbandEffect(for: buffer, base: vc.view.bounds.height)
+        }
+
+        // Rubberbanding bottom buffer
+        if behavior.allowsRubberBanding(for: .bottom), const > bottomMostConst {
+            let buffer = const - bottomMostConst
+            const = bottomMostConst + rubberbandEffect(for: buffer, base: vc.view.bounds.height)
+        }
+
+        interactiveTopConstraint?.constant = max(minConst, min(maxConst, 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(of state: FloatingPanelPosition) {
         defer {
             surfaceView.superview!.layoutIfNeeded()
+            log.debug("activateLayout -- surface.presentation = \(self.surfaceView.presentationFrame) surface.frame = \(self.surfaceView.frame)")
         }
 
         var state = state
 
         setBackdropAlpha(of: state)
 
+        // Must deactivate `interactiveTopConstraint` here
+        if let interactiveTopConstraint = interactiveTopConstraint {
+            NSLayoutConstraint.deactivate([interactiveTopConstraint])
+            self.interactiveTopConstraint = nil
+        }
         NSLayoutConstraint.activate(fixedConstraints)
 
-        if supportedPositions.union([.hidden]).contains(state) == false {
+        if isValid(state) == false {
             state = layout.initialPosition
         }
 
         NSLayoutConstraint.deactivate(fullConstraints + halfConstraints + tipConstraints + offConstraints)
         switch state {
         case .full:
-            NSLayoutConstraint.deactivate(halfConstraints + tipConstraints + offConstraints)
             NSLayoutConstraint.activate(fullConstraints)
         case .half:
-            NSLayoutConstraint.deactivate(fullConstraints + tipConstraints + offConstraints)
             NSLayoutConstraint.activate(halfConstraints)
         case .tip:
-            NSLayoutConstraint.deactivate(fullConstraints + halfConstraints + offConstraints)
             NSLayoutConstraint.activate(tipConstraints)
         case .hidden:
-            NSLayoutConstraint.deactivate(fullConstraints + halfConstraints + tipConstraints)
             NSLayoutConstraint.activate(offConstraints)
         }
     }
 
-    func setBackdropAlpha(of target: FloatingPanelPosition) {
+    func isValid(_ state: FloatingPanelPosition) -> Bool {
+        return supportedPositions.union([.hidden]).contains(state)
+    }
+
+    private func setBackdropAlpha(of target: FloatingPanelPosition) {
         if target == .hidden {
             self.backdropView.alpha = 0.0
         } else {
@@ -362,11 +497,11 @@ class FloatingPanelLayoutAdapter {
         }
     }
 
-    func checkLayoutConsistance() {
+    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))")
+               "Does not include an initial position (\(layout.initialPosition)) in supportedPositions (\(supportedPositions))")
 
         if layout is FloatingPanelIntrinsicLayout {
             assert(layout.insetFor(position: .full) == nil, "Return `nil` for full position on FloatingPanelIntrinsicLayout")
@@ -375,9 +510,47 @@ class FloatingPanelLayoutAdapter {
         if halfInset > 0 {
             assert(halfInset > tipInset, "Invalid half and tip insets")
         }
-        if fullInset > 0 {
+        // 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) }")
+         }*/
+    }
+
+    func segument(at posY: CGFloat, forward: Bool) -> LayoutSegment {
+        /// ----------------------->Y
+        /// --> forward                <-- backward
+        /// |-------|===o===|-------|  |-------|-------|===o===|
+        /// |-------|-------x=======|  |-------|=======x-------|
+        /// |-------|-------|===o===|  |-------|===o===|-------|
+        /// pos: o/x, seguement: =
+        let sortedPositions = supportedPositions.sorted(by: { $0.rawValue < $1.rawValue })
+
+        let upperIndex: Int?
+        if forward {
+            #if swift(>=4.2)
+            upperIndex = sortedPositions.firstIndex(where: { posY < positionY(for: $0) })
+            #else
+            upperIndex = sortedPositions.index(where: { posY < positionY(for: $0) })
+            #endif
+        } else {
+            #if swift(>=4.2)
+            upperIndex = sortedPositions.firstIndex(where: { posY <= positionY(for: $0) })
+            #else
+            upperIndex = sortedPositions.index(where: { posY <= positionY(for: $0) })
+            #endif
+        }
+
+        switch upperIndex {
+        case 0:
+            return LayoutSegment(lower: nil, upper: sortedPositions.first)
+        case let upperIndex?:
+            return LayoutSegment(lower: sortedPositions[upperIndex - 1], upper: sortedPositions[upperIndex])
+        default:
+            return LayoutSegment(lower: sortedPositions[sortedPositions.endIndex - 1], upper: nil)
         }
     }
 }

Framework/Sources/FloatingPanelSurfaceView.swift

@@ -5,27 +5,48 @@
 
 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!
+    /// to the surface view at appropriate coordinates.
+    public let grabberHandle: GrabberHandleView = GrabberHandleView()
+
+    /// Offset of the grabber handle from the top
+    public var grabberTopPadding: CGFloat = 6.0 { didSet {
+        setNeedsUpdateConstraints()
+    } }
 
     /// The height of the grabber bar area
-    public static var topGrabberBarHeight: CGFloat {
-        return Default.grabberTopPadding * 2 + GrabberHandleView.Default.height // 17.0
+    public var topGrabberBarHeight: CGFloat {
+        return grabberTopPadding * 2 + grabberHandleHeight
     }
 
-    /// A UIView object that can have the surface view added to it.
-    public var contentView: UIView!
+    /// Grabber view width and height
+    public var grabberHandleWidth: CGFloat = 36.0 { didSet {
+        setNeedsUpdateConstraints()
+    } }
+    public var grabberHandleHeight: CGFloat = 5.0 { didSet {
+        setNeedsUpdateConstraints()
+    } }
+
+    /// A root view of a content view controller
+    public weak var contentView: UIView!
+    
+    /// The content insets specifying the insets around the content view.
+    ///
+    /// - important: Currently the `bottom` inset is ignored.
+    public var contentInsets: UIEdgeInsets = .zero {
+        didSet {
+            // Needs update constraints
+            self.setNeedsUpdateConstraints()
+        }
+    }
 
     private var color: UIColor? = .white { didSet { setNeedsLayout() } }
-    private var bottomOverflow: CGFloat = 0.0 // Must not call setNeedsLayout()
+    var bottomOverflow: CGFloat = 0.0 // Must not call setNeedsLayout()
 
     public override var backgroundColor: UIColor? {
         get { return color }
@@ -36,7 +57,10 @@ public class FloatingPanelSurfaceView: UIView {
     ///
     /// `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() } }
+    public var cornerRadius: CGFloat {
+        set { containerView.layer.cornerRadius = newValue; setNeedsLayout() }
+        get { return containerView.layer.cornerRadius }
+    }
 
     /// A Boolean indicating whether the surface shadow is displayed.
     public var shadowHidden: Bool = false  { didSet { setNeedsLayout() } }
@@ -59,120 +83,154 @@ public class FloatingPanelSurfaceView: UIView {
     /// The color of the surface border.
     public var borderWidth: CGFloat = 0.0  { didSet { setNeedsLayout() } }
 
-    private var backgroundLayer: CAShapeLayer!  { didSet { setNeedsLayout() } }
+    /// Offset of the container view from the top
+    public var containerTopInset: CGFloat = 0.0 { didSet {
+        setNeedsUpdateConstraints()
+    } }
 
-    private struct Default {
-        public static let grabberTopPadding: CGFloat = 6.0
-    }
+    /// The view presents 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()
+
+    @available(*, unavailable, renamed: "containerView")
+    public var backgroundView: UIView!
+
+    private lazy var containerViewTopInsetConstraint: NSLayoutConstraint = containerView.topAnchor.constraint(equalTo: topAnchor, constant: containerTopInset)
+    private lazy var containerViewHeightConstraint: NSLayoutConstraint = containerView.heightAnchor.constraint(equalTo: heightAnchor, multiplier: 1.0)
+    
+    /// The content view top constraint
+    private var contentViewTopConstraint: NSLayoutConstraint?
+    /// The content view left constraint
+    private var contentViewLeftConstraint: NSLayoutConstraint?
+    /// The content right constraint
+    private var contentViewRightConstraint: NSLayoutConstraint?
+    /// The content height constraint
+    private var contentViewHeightConstraint: NSLayoutConstraint?
+
+    private lazy var grabberHandleWidthConstraint: NSLayoutConstraint = grabberHandle.widthAnchor.constraint(equalToConstant: grabberHandleWidth)
+    private lazy var grabberHandleHeightConstraint: NSLayoutConstraint = grabberHandle.heightAnchor.constraint(equalToConstant: grabberHandleHeight)
+    private lazy var grabberHandleTopConstraint: NSLayoutConstraint = grabberHandle.topAnchor.constraint(equalTo: topAnchor, constant: grabberTopPadding)
 
     override init(frame: CGRect) {
         super.init(frame: frame)
-        render()
+        addSubViews()
     }
 
-    required init?(coder aDecoder: NSCoder) {
+    required public init?(coder aDecoder: NSCoder) {
         super.init(coder: aDecoder)
-        render()
+        addSubViews()
     }
 
-    private func render() {
+    private func addSubViews() {
         super.backgroundColor = .clear
         self.clipsToBounds = false
 
-        let backgroundLayer = CAShapeLayer()
-        layer.insertSublayer(backgroundLayer, at: 0)
-        self.backgroundLayer = backgroundLayer
-
-        let contentView = FloatingPanelSurfaceContentView()
-        addSubview(contentView)
-        self.contentView = contentView as UIView
-        contentView.backgroundColor = color
-        contentView.translatesAutoresizingMaskIntoConstraints = false
+        addSubview(containerView)
+        containerView.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),
+            containerViewTopInsetConstraint,
+            containerView.leftAnchor.constraint(equalTo: leftAnchor, constant: 0.0),
+            containerView.rightAnchor.constraint(equalTo: rightAnchor, constant: 0.0),
+            containerViewHeightConstraint,
             ])
 
-        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),
+            grabberHandleWidthConstraint,
+            grabberHandleHeightConstraint,
+            grabberHandleTopConstraint,
             grabberHandle.centerXAnchor.constraint(equalTo: centerXAnchor),
             ])
     }
 
+    public override func updateConstraints() {
+        containerViewTopInsetConstraint.constant = containerTopInset
+        containerViewHeightConstraint.constant = bottomOverflow
+
+        contentViewTopConstraint?.constant = contentInsets.top
+        contentViewLeftConstraint?.constant = contentInsets.left
+        contentViewRightConstraint?.constant = contentInsets.right
+        contentViewHeightConstraint?.constant = -containerTopInset
+
+        grabberHandleTopConstraint.constant = grabberTopPadding
+        grabberHandleWidthConstraint.constant = grabberHandleWidth
+        grabberHandleHeightConstraint.constant = grabberHandleHeight
+
+        super.updateConstraints()
+    }
+
     public override func layoutSubviews() {
         super.layoutSubviews()
+        log.debug("surface view frame = \(frame)")
 
-        updateLayers()
-        updateContentViewMask()
+        containerView.backgroundColor = color
 
-        contentView.layer.borderColor = borderColor?.cgColor
-        contentView.layer.borderWidth = borderWidth
-        contentView.backgroundColor = color
+        updateShadow()
+        updateCornerRadius()
+        updateBorder()
     }
 
-    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
-		
+    private func updateShadow() {
         if shadowHidden == false {
-            layer.shadowColor = shadowColor.cgColor
-            layer.shadowOffset = shadowOffset
-            layer.shadowOpacity = shadowOpacity
-            layer.shadowRadius = shadowRadius
+            if #available(iOS 11, *) {
+                // For clear background. See also, https://github.com/SCENEE/FloatingPanel/pull/51.
+                layer.shadowColor = shadowColor.cgColor
+                layer.shadowOffset = shadowOffset
+                layer.shadowOpacity = shadowOpacity
+                layer.shadowRadius = shadowRadius
+            } else {
+                // Can't update `layer.shadow*` directly because of a UIVisualEffectView issue in iOS 10, https://forums.developer.apple.com/thread/50854
+                // Instead, a user should display shadow appropriately.
+            }
         }
     }
 
-    private func updateContentViewMask() {
+    private func updateCornerRadius() {
+        guard containerView.layer.cornerRadius != 0.0 else {
+            containerView.layer.masksToBounds = false
+            return
+        }
+        containerView.layer.masksToBounds = true
         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.
+            // 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.
-            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
+            containerView.layer.maskedCorners = [.layerMinXMinYCorner, .layerMaxXMinYCorner]
         } 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.
+            // 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.
         }
     }
 
-    func set(bottomOverflow: CGFloat) {
-        self.bottomOverflow = bottomOverflow
-        updateLayers()
-        updateContentViewMask()
+    private func updateBorder() {
+        containerView.layer.borderColor = borderColor?.cgColor
+        containerView.layer.borderWidth = borderWidth
     }
 
+    func add(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
 
-    func add(childView: UIView) {
-        contentView.addSubview(childView)
-        childView.frame = contentView.bounds
-        childView.translatesAutoresizingMaskIntoConstraints = false
+        let topConstraint = contentView.topAnchor.constraint(equalTo: topAnchor, constant: contentInsets.top)
+        let leftConstraint = contentView.leftAnchor.constraint(equalTo: leftAnchor, constant: contentInsets.left)
+        let rightConstraint = rightAnchor.constraint(equalTo: contentView.rightAnchor, constant: contentInsets.right)
+        let heightConstraint = contentView.heightAnchor.constraint(equalTo: heightAnchor, constant: -containerTopInset)
         NSLayoutConstraint.activate([
-            childView.topAnchor.constraint(equalTo: contentView.topAnchor, constant: 0.0),
-            childView.leftAnchor.constraint(equalTo: contentView.leftAnchor, constant: 0.0),
-            childView.rightAnchor.constraint(equalTo: contentView.rightAnchor, constant: 0.0),
-            childView.bottomAnchor.constraint(equalTo: contentView.bottomAnchor, constant: 0.0),
+            topConstraint,
+            leftConstraint,
+            rightConstraint,
+            heightConstraint,
             ])
+        self.contentViewTopConstraint = topConstraint
+        self.contentViewLeftConstraint = leftConstraint
+        self.contentViewRightConstraint = rightConstraint
+        self.contentViewHeightConstraint = heightConstraint
     }
 }

Framework/Sources/FloatingPanelTransitioning.swift

@@ -22,6 +22,12 @@ class FloatingPanelModalTransition: NSObject, UIViewControllerTransitioningDeleg
 }
 
 class FloatingPanelPresentationController: UIPresentationController {
+    override func presentationTransitionWillBegin() {
+        // Must call here even if duplicating on in containerViewWillLayoutSubviews()
+        // Because it let the floating panel present correctly with the presentation animation
+        addFloatingPanel()
+    }
+
     override func presentationTransitionDidEnd(_ completed: Bool) {
         // For non-animated presentation
         if let fpc = presentedViewController as? FloatingPanelController, fpc.position == .hidden {
@@ -30,29 +36,48 @@ class FloatingPanelPresentationController: UIPresentationController {
     }
 
     override func dismissalTransitionDidEnd(_ completed: Bool) {
-        // For non-animated dismissal
-        if let fpc = presentedViewController as? FloatingPanelController, fpc.position != .hidden {
-            fpc.hide(animated: false, completion: nil)
+        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
+            let fpc = presentedViewController as? FloatingPanelController
             else { fatalError() }
 
+        /*
+         * 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? FloatingPanelPassThroughView)?.eventForwardingView = presentingViewController.view
+
+        // Set tap-to-dismiss in the backdrop view
         let tapGesture = UITapGestureRecognizer(target: self, action: #selector(handleBackdrop(tapGesture:)))
         fpc.backdropView.addGestureRecognizer(tapGesture)
-
-        containerView.addSubview(fpView)
-        fpView.frame = containerView.bounds //MUST
     }
 
     @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 FloatingPanelModalPresentTransition: NSObject, UIViewControllerAnimatedTransitioning {

Framework/Sources/FloatingPanelView.swift

@@ -6,25 +6,14 @@
 import UIKit
 
 class FloatingPanelPassThroughView: UIView {
+    public weak var eventForwardingView: 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
+        let hitView = super.hitTest(point, with: event)
+        switch hitView {
+        case self:
+            return eventForwardingView?.hitTest(self.convert(point, to: eventForwardingView), with: event)
         default:
-            return view
-        }
-    }
-}
-
-class FloatingPanelSurfaceWrapperView: UIView {
-    public override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
-        let view = super.hitTest(point, with: event)
-        switch view {
-        case is FloatingPanelSurfaceWrapperView:
-            return nil
-        default:
-            return view
+            return hitView
         }
     }
 }

Framework/Sources/GrabberHandleView.swift

@@ -6,32 +6,30 @@
 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) {
+    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)
-        render()
     }
 
     init() {
-        let size = CGSize(width: Default.width,
-                          height: Default.height)
-        super.init(frame: CGRect(origin: .zero, size: size))
-        self.backgroundColor = Default.barColor
-        render()
+        super.init(frame: .zero)
+        backgroundColor = barColor
     }
 
-    private func render() {
-        self.layer.masksToBounds = true
-        self.layer.cornerRadius = frame.size.height * 0.5
+    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
+        self.layer.cornerRadius = frame.size.height * 0.5
+    }
 }

Framework/Sources/Info.plist

@@ -15,7 +15,7 @@
 	<key>CFBundlePackageType</key>
 	<string>FMWK</string>
 	<key>CFBundleShortVersionString</key>
-	<string>1.1.0</string>
+	<string>1.6.4</string>
 	<key>CFBundleVersion</key>
 	<string>$(CURRENT_PROJECT_VERSION)</string>
 </dict>

Framework/Sources/Logger.swift

@@ -19,29 +19,17 @@ struct Logger {
         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 {
+        var displayName: String {
             switch self {
             case .debug:
                 return "D/"
             case .info:
                 return "I/"
             case .warning:
-                return "W/"
+                return "Warning:"
             case .error:
-                return "E/"
-            case .fault:
-                return "F/"
+                return "Error:"
             }
         }
         @available(iOS 10.0, *)
@@ -49,31 +37,40 @@ struct Logger {
             switch self {
             case .debug: return .debug
             case .info: return .info
-            case .warning: return .info
+            case .warning: return .default
             case .error: return .error
-            case .fault: return .fault
             }
         }
 
-        public static func < (lhs: Logger.Level, rhs: Logger.Level) -> Bool {
+        static func < (lhs: Logger.Level, rhs: Logger.Level) -> Bool {
             return lhs.rawValue < rhs.rawValue
         }
     }
 
-    init() {
+    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], 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))"
+        let log: String = {
+            switch level {
+            case .debug:
+                return "\(level.displayName) \(message) \(extraMessage) (\(function):\(line))"
+            default:
+                return "\(level.displayName) \(message) \(extraMessage)"
+            }
+        }()
+
+        hook?(log, level)
 
         os_log("%@", log: osLog, type: level.osLogType, log)
-        #endif
     }
 
     private func getPrettyFunction(_ function: String, _ file: String) -> String {
@@ -85,7 +82,9 @@ struct Logger {
     }
 
     func debug(_ log: Any, _ arguments: Any..., function: String = #function, file: String  = #file, line: UInt = #line) {
+        #if __FP_LOG
         self.log(.debug, log, arguments, function: getPrettyFunction(function, file), line: line)
+        #endif
     }
 
     func info(_ log: Any, _ arguments: Any..., function: String = #function, file: String  = #file, line: UInt = #line) {
@@ -99,8 +98,4 @@ struct Logger {
     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

@@ -60,6 +60,10 @@ extension UIView {
             return self
         }
     }
+
+    var presentationFrame: CGRect {
+        return layer.presentation()?.frame ?? frame
+    }
 }
 
 extension UIView {
@@ -73,23 +77,43 @@ extension UIView {
     }
 }
 
+#if __FP_LOG
+#if swift(>=4.2)
 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"
+        case .began: return "began"
+        case .changed: return "changed"
+        case .failed: return "failed"
+        case .cancelled: return "cancelled"
+        case .ended: return "endeded"
+        case .possible: return "possible"
         }
     }
 }
+#else
+extension UIGestureRecognizerState: 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"
+        }
+    }
+}
+#endif
+#endif
 
 extension UIScrollView {
     var contentOffsetZero: CGPoint {
         return CGPoint(x: 0.0, y: 0.0 - contentInset.top)
     }
+    var isLocked: Bool {
+        return !showsVerticalScrollIndicator && !bounces &&  isDirectionalLockEnabled
+    }
 }
 
 extension UISpringTimingParameters {
@@ -100,3 +124,19 @@ extension UISpringTimingParameters {
         self.init(mass: mass, stiffness: stiffness, damping: damp, initialVelocity: initialVelocity)
     }
 }
+
+extension CGPoint {
+    static var nan: CGPoint {
+        return CGPoint(x: CGFloat.nan,
+                       y: CGFloat.nan)
+    }
+}
+
+extension UITraitCollection {
+    func shouldUpdateLayout(from previous: UITraitCollection) -> Bool {
+        return previous.horizontalSizeClass != horizontalSizeClass
+            || previous.verticalSizeClass != verticalSizeClass
+            || previous.preferredContentSizeCategory != preferredContentSizeCategory
+            || previous.layoutDirection != layoutDirection
+    }
+}

Framework/TestingApp/AppDelegate.swift

@@ -0,0 +1,22 @@
+//
+//  Created by Shin Yamamoto on 2018/11/01.
+//  Copyright © 2018 Shin Yamamoto. All rights reserved.
+//
+
+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
+    }
+}

Framework/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>

Framework/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>

Framework/Tests/FloatingPanelControllerTests.swift

@@ -0,0 +1,137 @@
+//
+//  Created by Shin Yamamoto on 2018/09/18.
+//  Copyright © 2018 Shin Yamamoto. All rights reserved.
+//
+
+import XCTest
+@testable import FloatingPanel
+
+class FloatingPanelControllerTests: XCTestCase {
+    override func setUp() {}
+    override func tearDown() {}
+
+    func test_warningRetainCycle() {
+        let myVC = MyZombieViewController(nibName: nil, bundle: nil)
+        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()
+            }
+        }
+        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)
+        XCTAssert(fpc.surfaceView.frame.minY ==  (fpc.view.bounds.height - fpc.layoutInsets.bottom) - fpc.layout.insetFor(position: .half)!)
+        fpc.move(to: .tip, animated: false)
+        XCTAssert(fpc.surfaceView.frame.minY == (fpc.view.bounds.height - fpc.layoutInsets.bottom) - fpc.layout.insetFor(position: .tip)!)
+    }
+
+    @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 nil
+            }
+        }
+        let myDelegate = MyDelegate()
+        let fpc = FloatingPanelController(delegate: myDelegate)
+        let traitCollection = UITraitCollection(traitsFrom: [fpc.traitCollection,
+                                                             UITraitCollection(userInterfaceStyle: .dark)])
+        XCTAssertEqual(traitCollection.userInterfaceStyle, .dark)
+        fpc.prepare(for: traitCollection)
+    }
+
+    func test_moveTo() {
+        let fpc = FloatingPanelController(delegate: nil)
+        fpc.showForTest()
+        fpc.move(to: .full, animated: false)
+        XCTAssertEqual(fpc.position, .full)
+        XCTAssertEqual(fpc.surfaceView.frame.minY, fpc.originYOfSurface(for: .full))
+
+        fpc.move(to: .half, animated: false)
+        XCTAssertEqual(fpc.position, .half)
+        XCTAssertEqual(fpc.surfaceView.frame.minY, fpc.originYOfSurface(for: .half))
+
+        fpc.move(to: .tip, animated: false)
+        XCTAssertEqual(fpc.position, .tip)
+        XCTAssertEqual(fpc.surfaceView.frame.minY, fpc.originYOfSurface(for: .tip))
+
+        fpc.move(to: .hidden, animated: false)
+        XCTAssertEqual(fpc.position, .hidden)
+        XCTAssertEqual(fpc.surfaceView.frame.minY, fpc.originYOfSurface(for: .hidden))
+
+        fpc.move(to: .full, animated: true)
+        waitRunLoop(secs: 0.3)
+        XCTAssertEqual(fpc.position, .full)
+        XCTAssertEqual(fpc.surfaceView.frame.minY, fpc.originYOfSurface(for: .full))
+
+        fpc.move(to: .half, animated: true)
+        waitRunLoop(secs: 0.3)
+        XCTAssertEqual(fpc.position, .half)
+        XCTAssertEqual(fpc.surfaceView.frame.minY, fpc.originYOfSurface(for: .half))
+
+        fpc.move(to: .tip, animated: true)
+        waitRunLoop(secs: 0.3)
+        XCTAssertEqual(fpc.position, .tip)
+        XCTAssertEqual(fpc.surfaceView.frame.minY, fpc.originYOfSurface(for: .tip))
+
+        fpc.move(to: .hidden, animated: true)
+        waitRunLoop(secs: 0.3)
+        XCTAssertEqual(fpc.position, .hidden)
+        XCTAssertEqual(fpc.surfaceView.frame.minY, fpc.originYOfSurface(for: .hidden))
+
+    }
+
+    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.surfaceView.frame.minY, fpc.originYOfSurface(for: .full))
+        fpc.move(to: .half, animated: false)
+        XCTAssertEqual(fpc.surfaceView.frame.minY, fpc.originYOfSurface(for: .half))
+        fpc.move(to: .tip, animated: false)
+        XCTAssertEqual(fpc.surfaceView.frame.minY, fpc.originYOfSurface(for: .tip))
+        fpc.move(to: .hidden, animated: false)
+        XCTAssertEqual(fpc.surfaceView.frame.minY, fpc.originYOfSurface(for: .hidden))
+    }
+}
+
+private class MyZombieViewController: UIViewController, FloatingPanelLayout, FloatingPanelBehavior, FloatingPanelControllerDelegate {
+    var fpc: FloatingPanelController?
+    override func viewDidLoad() {
+        fpc = FloatingPanelController(delegate: self)
+        fpc?.addPanel(toParent: self)
+    }
+    func floatingPanel(_ vc: FloatingPanelController, layoutFor newCollection: UITraitCollection) -> FloatingPanelLayout? {
+        return self
+    }
+
+    func floatingPanel(_ vc: FloatingPanelController, behaviorFor newCollection: UITraitCollection) -> FloatingPanelBehavior? {
+        return self
+    }
+    var initialPosition: FloatingPanelPosition {
+        return .half
+    }
+
+    func insetFor(position: FloatingPanelPosition) -> CGFloat? {
+        switch position {
+        case .full: return UIScreen.main.bounds.height == 667.0 ? 18.0 : 16.0
+        case .half: return 262.0
+        case .tip: return 69.0
+        case .hidden: return nil
+        }
+    }
+}

Framework/Tests/FloatingPanelLayoutTests.swift

@@ -0,0 +1,206 @@
+//
+//  Created by Shin Yamamoto on 2019/06/27.
+//  Copyright © 2019 scenee. All rights reserved.
+//
+
+import XCTest
+@testable import FloatingPanel
+
+class FloatingPanelLayoutTests: 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.topMostState, .full)
+        XCTAssertEqual(fpc.floatingPanel.layoutAdapter.bottomMostState, .tip)
+
+        class FloatingPanelLayoutWithHidden: FloatingPanelLayout {
+            func insetFor(position: FloatingPanelPosition) -> CGFloat? { return nil }
+            let initialPosition: FloatingPanelPosition = .hidden
+            let supportedPositions: Set<FloatingPanelPosition> = [.hidden, .half, .full]
+        }
+        class FloatingPanelLayout2Positions: FloatingPanelLayout {
+            func insetFor(position: FloatingPanelPosition) -> CGFloat? { return nil }
+            let initialPosition: FloatingPanelPosition = .tip
+            let supportedPositions: Set<FloatingPanelPosition> = [.tip, .half]
+        }
+        let delegate = FloatingPanelTestDelegate()
+        delegate.layout = FloatingPanelLayoutWithHidden()
+        fpc.delegate = delegate
+        XCTAssertEqual(fpc.floatingPanel.layoutAdapter.topMostState, .full)
+        XCTAssertEqual(fpc.floatingPanel.layoutAdapter.bottomMostState, .hidden)
+
+        delegate.layout = FloatingPanelLayout2Positions()
+        fpc.delegate = delegate
+        XCTAssertEqual(fpc.floatingPanel.layoutAdapter.topMostState, .half)
+        XCTAssertEqual(fpc.floatingPanel.layoutAdapter.bottomMostState, .tip)
+    }
+
+    func test_layoutSegment_3position() {
+        class FloatingPanelLayout3Positions: FloatingPanelTestLayout {
+            let initialPosition: FloatingPanelPosition = .half
+            let supportedPositions: Set<FloatingPanelPosition> = [.tip, .half, .full]
+        }
+
+        let delegate = FloatingPanelTestDelegate()
+        delegate.layout = FloatingPanelLayout3Positions()
+        fpc.delegate = delegate
+
+        let fullPos = fpc.originYOfSurface(for: .full)
+        let halfPos = fpc.originYOfSurface(for: .half)
+        let tipPos = fpc.originYOfSurface(for: .tip)
+
+        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 {
+            let initialPosition: FloatingPanelPosition = .half
+            let supportedPositions: Set<FloatingPanelPosition> = [.half, .full]
+        }
+
+        let delegate = FloatingPanelTestDelegate()
+        delegate.layout = FloatingPanelLayout2Positions()
+        fpc.delegate = delegate
+
+        let fullPos = fpc.originYOfSurface(for: .full)
+        let halfPos = fpc.originYOfSurface(for: .half)
+
+        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 {
+            let initialPosition: FloatingPanelPosition = .full
+            let supportedPositions: Set<FloatingPanelPosition> = [.full]
+        }
+
+        let delegate = FloatingPanelTestDelegate()
+        delegate.layout = FloatingPanelLayout1Positions()
+        fpc.delegate = delegate
+
+        let fullPos = fpc.originYOfSurface(for: .full)
+
+        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_updateInteractiveTopConstraint() {
+        fpc.showForTest()
+        fpc.move(to: .full, animated: false)
+
+        fpc.floatingPanel.layoutAdapter.startInteraction(at: fpc.position)
+        fpc.floatingPanel.layoutAdapter.startInteraction(at: fpc.position) // Should be ignore
+
+        let fullPos = fpc.originYOfSurface(for: .full)
+        let tipPos = fpc.originYOfSurface(for: .tip)
+
+        var pre: CGFloat
+        var next: CGFloat
+        pre = fpc.surfaceView.frame.minY
+        fpc.floatingPanel.layoutAdapter.updateInteractiveTopConstraint(diff: -100.0, allowsTopBuffer: false, with: fpc.behavior)
+        next = fpc.surfaceView.frame.minY
+        XCTAssertEqual(next, pre)
+
+        fpc.floatingPanel.layoutAdapter.updateInteractiveTopConstraint(diff: -100.0, allowsTopBuffer: true, with: fpc.behavior)
+        next = fpc.surfaceView.frame.minY
+        XCTAssertEqual(next, fullPos - fpc.layout.topInteractionBuffer)
+
+        fpc.floatingPanel.layoutAdapter.updateInteractiveTopConstraint(diff: 100.0, allowsTopBuffer: true, with: fpc.behavior)
+        next = fpc.surfaceView.frame.minY
+        XCTAssertEqual(next, fullPos + 100.0)
+
+        fpc.floatingPanel.layoutAdapter.updateInteractiveTopConstraint(diff: tipPos - fullPos, allowsTopBuffer: true, with: fpc.behavior)
+        next = fpc.surfaceView.frame.minY
+        XCTAssertEqual(next, tipPos)
+
+        fpc.floatingPanel.layoutAdapter.updateInteractiveTopConstraint(diff: tipPos - fullPos + 100.0, allowsTopBuffer: true, with: fpc.behavior)
+        next = fpc.surfaceView.frame.minY
+        XCTAssertEqual(next, tipPos + fpc.layout.bottomInteractionBuffer)
+
+        fpc.floatingPanel.layoutAdapter.endInteraction(at: fpc.position)
+    }
+
+    func test_updateInteractiveTopConstraintWithHidden() {
+        class FloatingPanelLayout2Positions: FloatingPanelTestLayout {
+            let initialPosition: FloatingPanelPosition = .hidden
+            let supportedPositions: Set<FloatingPanelPosition> = [.hidden, .full]
+        }
+        let delegate = FloatingPanelTestDelegate()
+        delegate.layout = FloatingPanelLayout2Positions()
+        fpc.delegate = delegate
+        fpc.showForTest()
+        fpc.move(to: .full, animated: false)
+
+        fpc.floatingPanel.layoutAdapter.startInteraction(at: fpc.position)
+
+        let fullPos = fpc.originYOfSurface(for: .full)
+        let hiddenPos = fpc.originYOfSurface(for: .hidden)
+
+        var pre: CGFloat
+        var next: CGFloat
+        pre = fpc.surfaceView.frame.minY
+        fpc.floatingPanel.layoutAdapter.updateInteractiveTopConstraint(diff: -100.0, allowsTopBuffer: false, with: fpc.behavior)
+        next = fpc.surfaceView.frame.minY
+        XCTAssertEqual(next, pre)
+
+        fpc.floatingPanel.layoutAdapter.updateInteractiveTopConstraint(diff: -100.0, allowsTopBuffer: true, with: fpc.behavior)
+        next = fpc.surfaceView.frame.minY
+        XCTAssertEqual(next, fullPos - fpc.layout.topInteractionBuffer)
+
+        fpc.floatingPanel.layoutAdapter.updateInteractiveTopConstraint(diff: hiddenPos - fullPos + 100.0, allowsTopBuffer: true, with: fpc.behavior)
+        next = fpc.surfaceView.frame.minY
+        XCTAssertEqual(next, hiddenPos + fpc.layout.bottomInteractionBuffer)
+
+        fpc.floatingPanel.layoutAdapter.endInteraction(at: fpc.position)
+    }
+}
+
+private typealias LayoutSegmentTestParameter = (UInt, pos: CGFloat, forwardY: Bool, lower: FloatingPanelPosition?, upper: FloatingPanelPosition?)
+private func assertLayoutSegment(_ floatingPanel: FloatingPanel, with params: [LayoutSegmentTestParameter]) {
+    params.forEach { (line, pos, forwardY, lowr, upper) in
+        let segument = floatingPanel.layoutAdapter.segument(at: pos, forward: forwardY)
+        XCTAssertEqual(segument.lower, lowr, line: line)
+        XCTAssertEqual(segument.upper, upper, line: line)
+    }
+}

Framework/Tests/FloatingPanelPositionTests.swift

@@ -0,0 +1,27 @@
+//
+//  Created by Shin Yamamoto on 2019/07/05.
+//  Copyright © 2019 scenee. All rights reserved.
+//
+
+import XCTest
+@testable import FloatingPanel
+
+class FloatingPanelPositionTests: XCTestCase {
+    override func setUp() { }
+    override func tearDown() { }
+
+    func test_nextAndPre() {
+        var positions: [FloatingPanelPosition]
+        positions = [.full, .half, .tip, .hidden]
+        XCTAssertEqual(FloatingPanelPosition.full.next(in: positions),  .half)
+        XCTAssertEqual(FloatingPanelPosition.full.pre(in: positions),  .full)
+        XCTAssertEqual(FloatingPanelPosition.hidden.next(in: positions), .hidden)
+        XCTAssertEqual(FloatingPanelPosition.hidden.pre(in: positions), .tip)
+
+        positions = [.full, .hidden]
+        XCTAssertEqual(FloatingPanelPosition.full.next(in: positions),  .hidden)
+        XCTAssertEqual(FloatingPanelPosition.full.pre(in: positions),  .full)
+        XCTAssertEqual(FloatingPanelPosition.hidden.next(in: positions), .hidden)
+        XCTAssertEqual(FloatingPanelPosition.hidden.pre(in: positions), .full)
+    }
+}

Framework/Tests/FloatingPanelSurfaceViewTests.swift

@@ -0,0 +1,85 @@
+//
+//  Created by Shin Yamamoto on 2019/05/23.
+//  Copyright © 2019 Shin Yamamoto. All rights reserved.
+//
+
+import XCTest
+@testable import FloatingPanel
+
+class FloatingPanelSurfaceViewTests: XCTestCase {
+    override func setUp() {}
+    override func tearDown() {}
+
+    func test_surfaceView() {
+        let surface = FloatingPanelSurfaceView(frame: CGRect(x: 0.0, y: 0.0, width: 320.0, height: 480.0))
+        XCTAssert(surface.contentView == nil)
+        surface.layoutIfNeeded()
+        XCTAssert(surface.grabberHandle.frame.minY == 6.0)
+        XCTAssert(surface.grabberHandle.frame.width == surface.grabberHandleWidth)
+        XCTAssert(surface.grabberHandle.frame.height == surface.grabberHandleHeight)
+        surface.backgroundColor = .red
+        surface.layoutIfNeeded()
+        XCTAssert(surface.backgroundColor == surface.containerView.backgroundColor)
+    }
+
+    func test_surfaceView_constraintsUpdate() {
+        let window = UIWindow()
+        let surface = FloatingPanelSurfaceView(frame: CGRect(x: 0.0, y: 0.0, width: 320.0, height: 480.0))
+        window.addSubview(surface)
+        window.makeKeyAndVisible()
+        XCTAssert(surface.contentView == nil)
+        surface.layoutIfNeeded()
+        XCTAssert(surface.grabberHandle.frame.minY == 6.0)
+        XCTAssert(surface.grabberHandle.frame.width == surface.grabberHandleWidth)
+        XCTAssert(surface.grabberHandle.frame.height == surface.grabberHandleHeight)
+
+        surface.grabberHandleWidth = 44.0
+        surface.grabberHandleHeight = 12.0
+        surface.layoutIfNeeded()
+        waitRunLoop(secs: 0.000_001)
+        XCTAssert(surface.grabberHandle.frame.width == surface.grabberHandleWidth, "\(surface.grabberHandle.frame.width) == \(surface.grabberHandleWidth)")
+        XCTAssert(surface.grabberHandle.frame.height == surface.grabberHandleHeight, "\(surface.grabberHandle.frame.height) == \(surface.grabberHandleHeight)")
+        window.resignKey()
+    }
+
+    func test_surfaceView_cornderRaduis() {
+        let surface = FloatingPanelSurfaceView(frame: CGRect(x: 0.0, y: 0.0, width: 320.0, height: 480.0))
+        XCTAssert(surface.cornerRadius == 0.0)
+        XCTAssert(surface.containerView.layer.masksToBounds == false)
+
+        surface.cornerRadius = 10.0
+        surface.layoutIfNeeded()
+        XCTAssert(surface.cornerRadius == 10.0)
+        XCTAssert(surface.containerView.layer.cornerRadius == 10.0)
+        XCTAssert(surface.containerView.layer.masksToBounds == true)
+
+        surface.containerView.layer.cornerRadius = 12.0
+        surface.layoutIfNeeded()
+        XCTAssert(surface.cornerRadius == 12.0)
+        XCTAssert(surface.containerView.layer.masksToBounds == true)
+
+        surface.cornerRadius = 0.0
+        surface.layoutIfNeeded()
+        XCTAssert(surface.cornerRadius == 0.0)
+        XCTAssert(surface.containerView.layer.cornerRadius == 0.0)
+        XCTAssert(surface.containerView.layer.masksToBounds == false)
+
+        surface.containerView.layer.cornerRadius = 12.0
+        surface.setNeedsLayout()
+        surface.layoutIfNeeded()
+        XCTAssert(surface.cornerRadius == 12.0)
+        XCTAssert(surface.containerView.layer.masksToBounds == true)
+    }
+
+    func test_surfaceView_border() {
+        let surface = FloatingPanelSurfaceView(frame: CGRect(x: 0.0, y: 0.0, width: 320.0, height: 480.0))
+        XCTAssert(surface.borderColor == nil)
+        XCTAssert(surface.borderWidth == 0.0)
+
+        surface.borderColor = .red
+        surface.borderWidth = 3.0
+        surface.layoutIfNeeded()
+        XCTAssert(surface.containerView.layer.borderColor == UIColor.red.cgColor)
+        XCTAssert(surface.containerView.layer.borderWidth == 3.0)
+    }
+}

Framework/Tests/FloatingPanelTests.swift

@@ -0,0 +1,537 @@
+//
+//  Created by Shin Yamamoto on 2019/05/23.
+//  Copyright © 2019 Shin Yamamoto. All rights reserved.
+//
+
+import XCTest
+@testable import FloatingPanel
+
+class FloatingPanelTests: 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.position, .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.position, .half)
+        XCTAssertEqual(contentVC2.tableView.showsVerticalScrollIndicator, false)
+        XCTAssertEqual(contentVC2.tableView.bounces, false)
+    }
+
+    func test_getBackdropAlpha_1positions() {
+        class FloatingPanelLayout1Positions: FloatingPanelTestLayout {
+            let initialPosition: FloatingPanelPosition = .full
+            let supportedPositions: Set<FloatingPanelPosition> = [.full]
+        }
+        let delegate = FloatingPanelTestDelegate()
+        delegate.layout = FloatingPanelLayout1Positions()
+
+        let fpc = FloatingPanelController(delegate: delegate)
+        fpc.showForTest()
+
+        let fullPos = fpc.originYOfSurface(for: .full)
+
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: fullPos - 100.0, with: CGPoint(x: 0.0, y: -100.0)), 0.3)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: fullPos, with: CGPoint(x: 0.0, y: 0.0)), 0.3)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: fullPos + 100.0, with: CGPoint(x: 0.0, y: 100.0)), 0.3) // ok??
+    }
+
+    func test_getBackdropAlpha_2positions() {
+        class FloatingPanelLayout2Positions: FloatingPanelTestLayout {
+            let initialPosition: FloatingPanelPosition = .half
+            let supportedPositions: Set<FloatingPanelPosition> = [.half, .full]
+        }
+        let delegate = FloatingPanelTestDelegate()
+        delegate.layout = FloatingPanelLayout2Positions()
+
+        let fpc = FloatingPanelController(delegate: delegate)
+        fpc.showForTest()
+
+        let fullPos = fpc.originYOfSurface(for: .full)
+        let halfPos = fpc.originYOfSurface(for: .half)
+        let distance1 = abs(halfPos - fullPos)
+
+        fpc.move(to: .full, animated: false)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: fullPos, with: CGPoint(x: 0.0, y: 0.0)), 0.3)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: fullPos + distance1 * 0.5, with: CGPoint(x: 0.0, y: distance1 * 0.5)), 0.3 * 0.5)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: halfPos, with: CGPoint(x: 0.0, y: distance1)), 0.0)
+
+        fpc.move(to: .half, animated: false)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: halfPos, with: CGPoint(x: 0.0, y: 0.0)), 0.0)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: fullPos + distance1 * 0.5, with: CGPoint(x: 0.0, y: -0.5 * distance1)), 0.3 * 0.5)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: fullPos, with: CGPoint(x: 0.0, y: -1 * distance1)), 0.3)
+    }
+
+    func test_getBackdropAlpha_2positionsWithHidden() {
+        class FloatingPanelLayout2Positions: FloatingPanelTestLayout {
+            let initialPosition: FloatingPanelPosition = .hidden
+            let supportedPositions: Set<FloatingPanelPosition> = [.hidden, .full]
+        }
+        let delegate = FloatingPanelTestDelegate()
+        delegate.layout = FloatingPanelLayout2Positions()
+
+        let fpc = FloatingPanelController(delegate: delegate)
+        fpc.showForTest()
+
+        let fullPos = fpc.originYOfSurface(for: .full)
+        let hiddenPos = fpc.originYOfSurface(for: .hidden)
+
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: fullPos - 100.0, with: CGPoint(x: 0.0, y: -100.0)), 0.3)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: fullPos, with: CGPoint(x: 0.0, y: 0.0)), 0.3)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: hiddenPos, with: CGPoint(x: 0.0, y: 100.0)), 0.0)
+    }
+
+    func test_getBackdropAlpha_3positions() {
+        let fpc = FloatingPanelController()
+        fpc.showForTest()
+
+        let fullPos = fpc.originYOfSurface(for: .full)
+        let halfPos = fpc.originYOfSurface(for: .half)
+        let tipPos = fpc.originYOfSurface(for: .tip)
+        let distance1 = abs(halfPos - fullPos)
+        let distance2 = abs(tipPos - halfPos)
+
+        fpc.move(to: .full, animated: false)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: fullPos, with: CGPoint(x: 0.0, y: 0.0)), 0.3)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: fullPos + distance1 * 0.5, with: CGPoint(x: 0.0, y: distance1 * 0.5)), 0.3 * 0.5)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: halfPos, with: CGPoint(x: 0.0, y: distance1)), 0.0)
+
+        fpc.move(to: .half, animated: false)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: halfPos, with: CGPoint(x: 0.0, y: 0.0)), 0.0)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: fullPos + distance1 * 0.5, with: CGPoint(x: 0.0, y: -0.5 * distance1)), 0.3 * 0.5)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: fullPos, with: CGPoint(x: 0.0, y: -1 * distance1)), 0.3)
+
+        fpc.move(to: .tip, animated: false)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: tipPos, with: CGPoint(x: 0.0, y: 0.0)), 0.0)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: halfPos + distance2 * 0.5, with: CGPoint(x: 0.0, y: -0.5 * distance2)), 0.0)
+        XCTAssertEqual(fpc.floatingPanel.getBackdropAlpha(at: halfPos, with: CGPoint(x: 0.0, y: -1 * distance2)), 0.0)
+    }
+
+    func test_targetPosition_1positions() {
+        class FloatingPanelLayout1Positions: FloatingPanelTestLayout {
+            let initialPosition: FloatingPanelPosition = .full
+            let supportedPositions: Set<FloatingPanelPosition> = [.full]
+        }
+        let delegate = FloatingPanelTestDelegate()
+        delegate.layout = FloatingPanelLayout1Positions()
+
+        let fpc = FloatingPanelController(delegate: delegate)
+        fpc.showForTest()
+
+        let fullPos = fpc.originYOfSurface(for: .full)
+
+        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: FloatingPanelTestLayout {
+            let initialPosition: FloatingPanelPosition = .half
+            let supportedPositions: Set<FloatingPanelPosition> = [.half, .full]
+        }
+        let delegate = FloatingPanelTestDelegate()
+        delegate.layout = FloatingPanelLayout2Positions()
+
+        let fpc = FloatingPanelController(delegate: delegate)
+        fpc.showForTest()
+
+        let fullPos = fpc.originYOfSurface(for: .full)
+        let halfPos = fpc.originYOfSurface(for: .half)
+
+        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: FloatingPanelTestLayout {
+            let initialPosition: FloatingPanelPosition = .hidden
+            let supportedPositions: Set<FloatingPanelPosition> = [.hidden, .full]
+        }
+        let delegate = FloatingPanelTestDelegate()
+        delegate.layout = FloatingPanelLayout2Positions()
+
+        let fpc = FloatingPanelController(delegate: delegate)
+        fpc.showForTest()
+
+        let fullPos = fpc.originYOfSurface(for: .full)
+        let hiddenPos = fpc.originYOfSurface(for: .hidden)
+
+        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_2positionsFromFull() {
+        let delegate = FloatingPanelTestDelegate()
+        delegate.layout = FloatingPanelLayout3Positions()
+        let fpc = FloatingPanelController(delegate: delegate)
+        fpc.showForTest()
+
+        let fullPos = fpc.originYOfSurface(for: .full)
+        let halfPos = fpc.originYOfSurface(for: .half)
+        let tipPos = fpc.originYOfSurface(for: .tip)
+        // 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_3positionsFromHalf() {
+        let delegate = FloatingPanelTestDelegate()
+        delegate.layout = FloatingPanelLayout3Positions()
+        let fpc = FloatingPanelController(delegate: delegate)
+        fpc.showForTest()
+
+        let fullPos = fpc.originYOfSurface(for: .full)
+        let halfPos = fpc.originYOfSurface(for: .half)
+        let tipPos = fpc.originYOfSurface(for: .tip)
+        // 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_3positionsFromTip() {
+        let delegate = FloatingPanelTestDelegate()
+        delegate.layout = FloatingPanelLayout3Positions()
+        let fpc = FloatingPanelController(delegate: delegate)
+        fpc.showForTest()
+
+        let fullPos = fpc.originYOfSurface(for: .full)
+        let halfPos = fpc.originYOfSurface(for: .half)
+        let tipPos = fpc.originYOfSurface(for: .tip)
+
+        // 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_3positionsAllProjection() {
+        let delegate = FloatingPanelTestDelegate()
+        delegate.layout = FloatingPanelLayout3Positions()
+        delegate.behavior = FloatingPanelProjectionalBehavior()
+
+        let fpc = FloatingPanelController(delegate: delegate)
+        fpc.showForTest()
+
+        let fullPos = fpc.originYOfSurface(for: .full)
+        let halfPos = fpc.originYOfSurface(for: .half)
+        let tipPos = fpc.originYOfSurface(for: .tip)
+
+        // 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: FloatingPanelTestLayout {
+            let initialPosition: FloatingPanelPosition = .hidden
+            let supportedPositions: Set<FloatingPanelPosition> = [.hidden, .half, .full]
+        }
+        let delegate = FloatingPanelTestDelegate()
+        delegate.layout = FloatingPanelLayout3PositionsWithHidden()
+
+        let fpc = FloatingPanelController(delegate: delegate)
+        fpc.showForTest()
+        XCTAssertEqual(fpc.position, .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: FloatingPanelTestLayout {
+            let initialPosition: FloatingPanelPosition = .hidden
+            let supportedPositions: Set<FloatingPanelPosition> = [.hidden, .tip, .half]
+        }
+
+        let delegate = FloatingPanelTestDelegate()
+        delegate.layout = FloatingPanelLayout3Positions()
+        delegate.behavior = FloatingPanelProjectionalBehavior()
+
+        let fpc = FloatingPanelController(delegate: delegate)
+        fpc.showForTest()
+        XCTAssertEqual(fpc.position, .hidden)
+
+        let halfPos = fpc.originYOfSurface(for: .half)
+        let tipPos = fpc.originYOfSurface(for: .tip)
+        //let hiddenPos = fpc.originYOfSurface(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 {
+    let initialPosition: FloatingPanelPosition = .tip
+    let supportedPositions: Set<FloatingPanelPosition> = [.tip, .half, .full]
+}
+
+private typealias TestParameter = (UInt, CGFloat,CGPoint, FloatingPanelPosition)
+private func assertTargetPosition(_ floatingPanel: FloatingPanel, with params: [TestParameter]) {
+    params.forEach { (line, pos, velocity, result) in
+        floatingPanel.surfaceView.frame.origin.y = pos
+        XCTAssertEqual(floatingPanel.targetPosition(from: pos, with: velocity), result, line: line)
+    }
+}
+
+private class FloatingPanelProjectionalBehavior: FloatingPanelBehavior {
+    func shouldProjectMomentum(_ fpc: FloatingPanelController, for proposedTargetPosition: FloatingPanelPosition) -> Bool {
+        return true
+    }
+}

Framework/Tests/Utils.swift

@@ -0,0 +1,42 @@
+//
+//  Created by Shin Yamamoto on 2019/06/27.
+//  Copyright © 2019 scenee. All rights reserved.
+//
+
+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 layout: FloatingPanelLayout?
+    var behavior: FloatingPanelBehavior?
+    func floatingPanel(_ vc: FloatingPanelController, layoutFor newCollection: UITraitCollection) -> FloatingPanelLayout? {
+        return layout
+    }
+    func floatingPanel(_ vc: FloatingPanelController, behaviorFor newCollection: UITraitCollection) -> FloatingPanelBehavior? {
+        return behavior
+    }
+}
+
+protocol FloatingPanelTestLayout: FloatingPanelFullScreenLayout {}
+extension FloatingPanelTestLayout {
+    func insetFor(position: FloatingPanelPosition) -> CGFloat? {
+        switch position {
+        case .full: return 20.0
+        case .half: return 250.0
+        case .tip: return 60.0
+        default: return nil
+        }
+    }
+}

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() {}
-}

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: "Framework/Sources"),
+    ],
+    swiftLanguageVersions: [.version("5")]
+)

README.md

@@ -2,7 +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 4.1](https://img.shields.io/badge/Swift-4.1-orange.svg?style=flat)](https://swift.org/)
 [![Swift 4.2](https://img.shields.io/badge/Swift-4.2-orange.svg?style=flat)](https://swift.org/)
+[![Swift 5.0](https://img.shields.io/badge/Swift-5.0-orange.svg?style=flat)](https://swift.org/)
 
 #  FloatingPanel
 
@@ -25,6 +27,7 @@ The new interface displays the related contents and utilities in parallel as a u
 - [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)
+- [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)
@@ -65,7 +68,9 @@ Examples are here.
 
 ## Requirements
 
-FloatingPanel is written in Swift 4.2. Compatible with iOS 10.0+
+FloatingPanel is written in Swift 4.0+. It can be built by Xcode 9.4.1 or later. Compatible with iOS 10.0+.
+
+✏️ The default Swift version is 4.0 because it avoids build errors with Carthage on each Xcode version from the source compatibility between Swift 4.0, 4.2 and 5.0.
 
 ## Installation
 
@@ -78,6 +83,8 @@ it, simply add the following line to your Podfile:
 pod 'FloatingPanel'
 ```
 
+✏️ To suppress "Swift Conversion" warnings in Xcode, please set a Swift version to `SWIFT_VERSION` for the project in your Podfile. It will be resolved in CocoaPods v1.7.0.
+
 ### Carthage
 
 For [Carthage](https://github.com/Carthage/Carthage), add the following to your `Cartfile`:
@@ -86,6 +93,9 @@ For [Carthage](https://github.com/Carthage/Carthage), add the following to your
 github "scenee/FloatingPanel"
 ```
 
+### Swift Package Manager with Xcode 11
+
+Follow [this doc](https://developer.apple.com/documentation/swift_packages/adding_package_dependencies_to_your_app).
 
 ## Getting Started
 
@@ -138,9 +148,22 @@ 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).
+✏️ FloatingPanelController has the custom presentation controller. If you would like to customize the presentation/dismissal, please see [FloatingPanelTransitioning](https://github.com/SCENEE/FloatingPanel/blob/master/Framework/Sources/FloatingPanelTransitioning.swift).
+
+## View hierarchy
+
+`FloatingPanelController` manages the views as the following view hierarchy.
+
+```
+FloatingPanelController.view (FloatingPanelPassThroughView)
+ ├─ .backdropView (FloatingPanelBackdropView)
+ └─ .surfaceView (FloatingPanelSurfaceView)
+    ├─ .containerView (UIView)
+    │  └─ .contentView (FloatingPanelController.contentViewController.view)
+    └─ .grabberHandle (GrabberHandleView)
+```
 
 ## Usage
 
@@ -150,7 +173,15 @@ NOTE: FloatingPanelController has the custom presentation controller. If you wou
 // Add the controller and the managed views to a view controller.
 // From the second time, just call `show(animated:completion)`.
 view.addSubview(fpc.view)
+
 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([...])
+// 
+
 parent.addChild(fpc)
 
 // Show a floating panel to the initial position defined in your `FloatingPanelLayout` object.
@@ -230,7 +261,7 @@ class FloatingPanelLandscapeLayout: FloatingPanelLayout {
 
     public func prepareLayout(surfaceView: UIView, in view: UIView) -> [NSLayoutConstraint] {
         return [
-            surfaceView.leftAnchor.constraint(equalTo: view.safeAreaLayoutGuid.leftAnchor, constant: 8.0),
+            surfaceView.leftAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leftAnchor, constant: 8.0),
             surfaceView.widthAnchor.constraint(equalToConstant: 291),
         ]
     }