Release v1.5.0

The default Swift version leaves 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.

With regard to CocoaPods, the pod spec is going to support
`swift_versions` introduced in CocoaPods v1.7.0. For now, a user needs
to override `SWIFT_VERSION` appropriately in Podfile.

.travis.yml

@@ -2,7 +2,6 @@ language: swift
 branches:
   only:
     - master
-    - next
 cache:
   directories:
   - /usr/local/Homebrew
@@ -19,15 +18,20 @@ jobs:
   - stage: Build framework(swift 4.1)
     osx_image: xcode9.4
     script:
-    - xcodebuild -scheme FloatingPanel clean build
+    - xcodebuild -scheme FloatingPanel SWIFT_VERSION=4.1 clean build
 
   - stage: Build framework(swift 4.2)
     osx_image: xcode10
     script:
-    - xcodebuild -scheme FloatingPanel clean build
+    - xcodebuild -scheme FloatingPanel SWIFT_VERSION=4.2 clean build
+
+  - stage: Build framework(swift 5.0)
+    osx_image: xcode10.2
+    script:
+    - xcodebuild -scheme FloatingPanel SWIFT_VERSION=5.0 clean build
 
   - stage: Carthage
-    osx_image: xcode10
+    osx_image: xcode10.2
     before_install:
     - brew update
     - brew outdated carthage || brew upgrade carthage
@@ -35,21 +39,21 @@ jobs:
     - carthage build --no-skip-current
 
   - stage: Podspec
-    osx_image: xcode10
+    osx_image: xcode10.2
     script:
     - pod spec lint
 
   - stage: Build maps example
-    osx_image: xcode10
+    osx_image: xcode10.2
     script:
     - xcodebuild -scheme Maps -sdk iphonesimulator clean build
 
   - stage: Build stocks example
-    osx_image: xcode10
+    osx_image: xcode10.2
     script:
     - xcodebuild -scheme Stocks -sdk iphonesimulator clean build
 
   - stage: Build samples example
-    osx_image: xcode10
+    osx_image: xcode10.2
     script:
     - xcodebuild -scheme Samples -sdk iphonesimulator clean build

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/Samples/Samples.xcodeproj/project.pbxproj

@@ -499,7 +499,7 @@
 				);
 				PRODUCT_BUNDLE_IDENTIFIER = com.scenee.FloatingPanelSample;
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 4.2;
+				SWIFT_VERSION = 5.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 			};
 			name = Debug;
@@ -518,7 +518,7 @@
 				);
 				PRODUCT_BUNDLE_IDENTIFIER = com.scenee.FloatingPanelSample;
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 4.2;
+				SWIFT_VERSION = 5.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 			};
 			name = Release;

Examples/Samples/Sources/ViewController.swift

@@ -9,6 +9,11 @@
 import UIKit
 import FloatingPanel
 
+/**
+ - 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.
+ */
 class SampleListViewController: UIViewController, UITableViewDataSource, UITableViewDelegate, FloatingPanelControllerDelegate, FloatingPanelLayout {
     @IBOutlet weak var tableView: UITableView!
 
@@ -828,6 +833,15 @@ class TabBarContentViewController: UIViewController {
 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 implicity reset the offset(i.e.
+        // Using KVO of `scrollView.contentOffset`). Because it can lead to an
+        // infinit 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
+        }
     }
 }
 

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             = "1.4.0"
+  s.version             = "1.5.0"
   s.summary             = "FloatingPanel is a clean and easy-to-use UI component of a floating panel interface."
   s.description         = <<-DESC
 FloatingPanel is a clean and easy-to-use UI component for a new interface introduced in Apple Maps, Shortcuts and Stocks app.

Framework/FloatingPanel.xcodeproj/project.pbxproj

@@ -11,8 +11,8 @@
 		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 /* FloatingPanelTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 545DB9CF2151169500CA77B8 /* FloatingPanelTests.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 */; };
@@ -38,10 +38,10 @@
 		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>"; };
 		545DB9CA2151169500CA77B8 /* FloatingPanelTests.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = FloatingPanelTests.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
-		545DB9CF2151169500CA77B8 /* ViewTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ViewTests.swift; sourceTree = "<group>"; };
+		545DB9CF2151169500CA77B8 /* FloatingPanelTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FloatingPanelTests.swift; sourceTree = "<group>"; };
 		545DB9D12151169500CA77B8 /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
 		545DB9DD215118C800CA77B8 /* UIExtensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = UIExtensions.swift; sourceTree = "<group>"; };
 		545DB9DF21511AC100CA77B8 /* FloatingPanelController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FloatingPanelController.swift; sourceTree = "<group>"; };
@@ -94,7 +94,7 @@
 			isa = PBXGroup;
 			children = (
 				545DB9C52151169500CA77B8 /* Info.plist */,
-				545DB9C42151169500CA77B8 /* FloatingPanelController.h */,
+				545DB9C42151169500CA77B8 /* FloatingPanel.h */,
 				545DB9DF21511AC100CA77B8 /* FloatingPanelController.swift */,
 				54352E9521A51A2500CBCA08 /* FloatingPanelTransitioning.swift */,
 				54CFBFC4215CD09C006B5735 /* FloatingPanel.swift */,
@@ -113,7 +113,7 @@
 		545DB9CE2151169500CA77B8 /* Tests */ = {
 			isa = PBXGroup;
 			children = (
-				545DB9CF2151169500CA77B8 /* ViewTests.swift */,
+				545DB9CF2151169500CA77B8 /* FloatingPanelTests.swift */,
 				545DB9D12151169500CA77B8 /* Info.plist */,
 			);
 			path = Tests;
@@ -126,7 +126,7 @@
 			isa = PBXHeadersBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
-				545DB9D22151169500CA77B8 /* FloatingPanelController.h in Headers */,
+				545DB9D22151169500CA77B8 /* FloatingPanel.h in Headers */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -246,7 +246,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
-				545DB9D02151169500CA77B8 /* ViewTests.swift in Sources */,
+				545DB9D02151169500CA77B8 /* FloatingPanelTests.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -473,6 +473,116 @@
 			};
 			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",
+					"$(inherited)",
+				);
+				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
+				GCC_WARN_ABOUT_RETURN_TYPE = YES_ERROR;
+				GCC_WARN_UNDECLARED_SELECTOR = YES;
+				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
+				GCC_WARN_UNUSED_FUNCTION = YES;
+				GCC_WARN_UNUSED_VARIABLE = YES;
+				IPHONEOS_DEPLOYMENT_TARGET = 12.0;
+				MTL_ENABLE_DEBUG_INFO = INCLUDE_SOURCE;
+				MTL_FAST_MATH = YES;
+				ONLY_ACTIVE_ARCH = YES;
+				SDKROOT = iphoneos;
+				SWIFT_ACTIVE_COMPILATION_CONDITIONS = DEBUG;
+				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
+				VERSIONING_SYSTEM = "apple-generic";
+				VERSION_INFO_PREFIX = "";
+			};
+			name = Test;
+		};
+		54E79AE0224F6C9800717BC6 /* Test */ = {
+			isa = XCBuildConfiguration;
+			buildSettings = {
+				CLANG_ENABLE_MODULES = YES;
+				CODE_SIGN_IDENTITY = "";
+				CODE_SIGN_STYLE = Automatic;
+				DEFINES_MODULE = YES;
+				DYLIB_COMPATIBILITY_VERSION = 1;
+				DYLIB_CURRENT_VERSION = 1;
+				DYLIB_INSTALL_NAME_BASE = "@rpath";
+				INFOPLIST_FILE = Sources/Info.plist;
+				INSTALL_PATH = "$(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_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;
+				INFOPLIST_FILE = Tests/Info.plist;
+				LD_RUNPATH_SEARCH_PATHS = (
+					"$(inherited)",
+					"@executable_path/Frameworks",
+					"@loader_path/Frameworks",
+				);
+				PRODUCT_BUNDLE_IDENTIFIER = com.scenee.FloatingModalControllerTests;
+				PRODUCT_NAME = "$(TARGET_NAME)";
+				SWIFT_VERSION = 4.2;
+				TARGETED_DEVICE_FAMILY = "1,2";
+			};
+			name = Test;
+		};
 /* End XCBuildConfiguration section */
 
 /* Begin XCConfigurationList section */
@@ -480,6 +590,7 @@
 			isa = XCConfigurationList;
 			buildConfigurations = (
 				545DB9D32151169500CA77B8 /* Debug */,
+				54E79ADF224F6C9800717BC6 /* Test */,
 				545DB9D42151169500CA77B8 /* Release */,
 			);
 			defaultConfigurationIsVisible = 0;
@@ -489,6 +600,7 @@
 			isa = XCConfigurationList;
 			buildConfigurations = (
 				545DB9D62151169500CA77B8 /* Debug */,
+				54E79AE0224F6C9800717BC6 /* Test */,
 				545DB9D72151169500CA77B8 /* Release */,
 			);
 			defaultConfigurationIsVisible = 0;
@@ -498,6 +610,7 @@
 			isa = XCConfigurationList;
 			buildConfigurations = (
 				545DB9D92151169500CA77B8 /* Debug */,
+				54E79AE1224F6C9800717BC6 /* Test */,
 				545DB9DA2151169500CA77B8 /* Release */,
 			);
 			defaultConfigurationIsVisible = 0;

Framework/FloatingPanel.xcodeproj/xcshareddata/xcschemes/FloatingPanel.xcscheme

@@ -23,12 +23,31 @@
       </BuildActionEntries>
    </BuildAction>
    <TestAction
-      buildConfiguration = "Debug"
+      buildConfiguration = "Test"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
       shouldUseLaunchSchemeArgsEnv = "YES">
       <Testables>
+         <TestableReference
+            skipped = "NO">
+            <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/FloatingPanel.swift

@@ -25,7 +25,6 @@ class FloatingPanel: NSObject, UIGestureRecognizerDelegate, UIScrollViewDelegate
             scrollIndictorVisible = scrollView.showsVerticalScrollIndicator
         }
     }
-    weak var userScrollViewDelegate: UIScrollViewDelegate?
 
     private(set) var state: FloatingPanelPosition = .hidden {
         didSet { viewcontroller.delegate?.floatingPanelDidChangePosition(viewcontroller) }
@@ -40,6 +39,7 @@ class FloatingPanel: NSObject, UIGestureRecognizerDelegate, UIScrollViewDelegate
     var isRemovalInteractionEnabled: Bool = false
 
     fileprivate var animator: UIViewPropertyAnimator?
+
     private var initialFrame: CGRect = .zero
     private var initialTranslationY: CGFloat = 0
     private var initialLocation: CGPoint = .nan
@@ -91,7 +91,7 @@ class FloatingPanel: NSObject, UIGestureRecognizerDelegate, UIScrollViewDelegate
     }
 
     private func move(from: FloatingPanelPosition, to: FloatingPanelPosition, animated: Bool, completion: (() -> Void)? = nil) {
-        if to != .full {
+        if state != layoutAdapter.topMostState {
             lockScrollView()
         }
         tearDownActiveInteraction()
@@ -252,34 +252,25 @@ class FloatingPanel: NSObject, UIGestureRecognizerDelegate, UIScrollViewDelegate
 
             if belowTop {
                 // Scroll offset pinning
-                switch state {
-                case .full:
+                if state == layoutAdapter.topMostState {
                     if interactionInProgress {
                         log.debug("settle offset --", initialScrollOffset.y)
                         scrollView.setContentOffset(initialScrollOffset, animated: false)
                     } else {
                         if grabberAreaFrame.contains(location) {
                             // Preserve the current content offset in moving from full.
-                            scrollView.contentOffset.y = initialScrollOffset.y
+                            scrollView.setContentOffset(initialScrollOffset, animated: false)
                         } else {
-                            if scrollView.contentOffset.y < 0 {
+                            let offset = scrollView.contentOffset.y - scrollView.contentOffsetZero.y
+                            if offset < 0 {
                                 fitToBounds(scrollView: scrollView)
                                 let translation = panGesture.translation(in: panGestureRecognizer.view!.superview)
                                 startInteraction(with: translation, at: location)
                             }
                         }
                     }
-                case .half, .tip:
-                    guard scrollView.isDecelerating == false else {
-                        // Don't fix the scroll offset in animating the panel to half and tip.
-                        // It causes a buggy scrolling deceleration because `state` becomes
-                        // a target position in animating the panel on the interaction from full.
-                        return
-                    }
-                    // Fix the scroll offset in moving the panel from half and tip.
-                    scrollView.contentOffset.y = initialScrollOffset.y
-                case .hidden:
-                    break
+                } else {
+                    scrollView.setContentOffset(initialScrollOffset, animated: false)
                 }
 
                 // Always hide a scroll indicator at the non-top.
@@ -291,7 +282,8 @@ class FloatingPanel: NSObject, UIGestureRecognizerDelegate, UIScrollViewDelegate
                 if interactionInProgress {
                     unlockScrollView()
                 } else {
-                    if state == .full, scrollView.contentOffset.y < 0, velocity.y > 0 {
+                    let offset = scrollView.contentOffset.y - scrollView.contentOffsetZero.y
+                    if state == layoutAdapter.topMostState, offset < 0, velocity.y > 0 {
                         fitToBounds(scrollView: scrollView)
                         let translation = panGesture.translation(in: panGestureRecognizer.view!.superview)
                         startInteraction(with: translation, at: location)
@@ -306,11 +298,18 @@ class FloatingPanel: NSObject, UIGestureRecognizerDelegate, UIScrollViewDelegate
                 "translation =  \(translation.y), location = \(location.y), velocity = \(velocity.y)")
 
             if let animator = self.animator {
+                log.debug("panel animation interrupted!!!")
                 if animator.isInterruptible {
                     animator.stopAnimation(false)
                     animator.finishAnimation(at: .current)
                 }
+
                 self.animator = nil
+
+                // A user can stop a panel at the nearest Y of a target position
+                if abs(surfaceView.frame.minY - layoutAdapter.topY) < 1 {
+                    surfaceView.frame.origin.y = layoutAdapter.topY
+                }
             }
 
             if interactionInProgress == false,
@@ -360,8 +359,9 @@ class FloatingPanel: NSObject, UIGestureRecognizerDelegate, UIScrollViewDelegate
         }
 
         guard
-            state == .full,                   // When not .full, don't scroll.
-            interactionInProgress == false    // When interaction already in progress, don't scroll.
+            state == layoutAdapter.topMostState,   // When not top most(i.e. .full), don't scroll.
+            interactionInProgress == false,        // When interaction already in progress, don't scroll.
+            surfaceView.frame.minY == layoutAdapter.topY
         else {
             return false
         }
@@ -379,18 +379,15 @@ class FloatingPanel: NSObject, UIGestureRecognizerDelegate, UIScrollViewDelegate
         }
 
         let offset = scrollView.contentOffset.y - scrollView.contentOffsetZero.y
-        // 10 pt is introduced from my testing(there might be better one)
-        // It should be low as possible because a user scroll view frame will
-        // change as far as the specified value temporarily.
-        // The zero offset is an exception because the offset is usually zero
-        // when a panel moves from half or tip position to full.
-        if  offset > -10.0, offset != 0.0 {
+        // The zero offset must be excluded because the offset is usually zero
+        // after a panel moves from half/tip to full.
+        if  offset > 0.0 {
             return true
         }
         if scrollView.isDecelerating {
             return true
         }
-        if velocity.y < 0 {
+        if velocity.y <= 0 {
             return true
         }
 
@@ -403,12 +400,11 @@ class FloatingPanel: NSObject, UIGestureRecognizerDelegate, UIScrollViewDelegate
         // So here just preserve the current state if needed.
         log.debug("panningBegan -- location = \(location.y)")
         initialLocation = location
-        switch state {
-        case .full:
+        if state == layoutAdapter.topMostState {
             if let scrollView = scrollView {
                 initialScrollFrame = scrollView.frame
             }
-        default:
+        } else {
             if let scrollView = scrollView {
                 initialScrollOffset = scrollView.contentOffset
             }
@@ -492,6 +488,12 @@ class FloatingPanel: NSObject, UIGestureRecognizerDelegate, UIScrollViewDelegate
         }
 
         stopScrollDeceleration = (surfaceView.frame.minY > layoutAdapter.topY) // Projecting the dragging to the scroll dragging or not
+        if stopScrollDeceleration {
+            DispatchQueue.main.async { [weak self] in
+                guard let `self` = self else { return }
+                self.stopScrollingWithDeceleration(at: self.initialScrollOffset)
+            }
+        }
 
         let targetPosition = self.targetPosition(with: velocity)
         let distance = self.distance(to: targetPosition)
@@ -500,7 +502,7 @@ class FloatingPanel: NSObject, UIGestureRecognizerDelegate, UIScrollViewDelegate
 
         if isRemovalInteractionEnabled, isBottomState {
             let velocityVector = (distance != 0) ? CGVector(dx: 0,
-                                                            dy: min(fabs(velocity.y)/distance, behavior.removalVelocity)) : .zero
+                                                            dy: min(abs(velocity.y)/distance, behavior.removalVelocity)) : .zero
 
             if shouldStartRemovalAnimation(with: velocityVector) {
 
@@ -518,7 +520,19 @@ class FloatingPanel: NSObject, UIGestureRecognizerDelegate, UIScrollViewDelegate
 
         viewcontroller.delegate?.floatingPanelDidEndDragging(viewcontroller, withVelocity: velocity, targetPosition: targetPosition)
 
+        // Workaround: Disable a tracking scroll to prevent bouncing a scroll content in a panel animating
+        let isScrollEnabled = scrollView?.isScrollEnabled
+        if let scrollView = scrollView, targetPosition != .full {
+            scrollView.isScrollEnabled = false
+        }
+
         startAnimation(to: targetPosition, at: distance, with: velocity)
+
+        // Workaround: Reset `self.scrollView.isScrollEnabled`
+        if let scrollView = scrollView, targetPosition != .full,
+            let isScrollEnabled = isScrollEnabled {
+            scrollView.isScrollEnabled = isScrollEnabled
+        }
     }
 
     private func shouldStartRemovalAnimation(with velocityVector: CGVector) -> Bool {
@@ -557,7 +571,7 @@ class FloatingPanel: NSObject, UIGestureRecognizerDelegate, UIScrollViewDelegate
         guard interactionInProgress == false else { return }
 
         initialFrame = surfaceView.frame
-        if state == .full, let scrollView = scrollView {
+        if state == layoutAdapter.topMostState, let scrollView = scrollView {
             if grabberAreaFrame.contains(location) {
                 initialScrollOffset = scrollView.contentOffset
             } else {
@@ -586,7 +600,7 @@ class FloatingPanel: NSObject, UIGestureRecognizerDelegate, UIScrollViewDelegate
         interactionInProgress = false
 
         // Prevent to keep a scroll view indicator visible at the half/tip position
-        if targetPosition != .full {
+        if state != layoutAdapter.topMostState {
             lockScrollView()
         }
 
@@ -605,7 +619,7 @@ class FloatingPanel: NSObject, UIGestureRecognizerDelegate, UIScrollViewDelegate
         isDecelerating = true
         viewcontroller.delegate?.floatingPanelWillBeginDecelerating(viewcontroller)
 
-        let velocityVector = (distance != 0) ? CGVector(dx: 0, dy: min(fabs(velocity.y)/distance, 30.0)) : .zero
+        let velocityVector = (distance != 0) ? CGVector(dx: 0, dy: min(abs(velocity.y)/distance, 30.0)) : .zero
         let animator = behavior.interactionAnimator(self.viewcontroller, to: targetPosition, with: velocityVector)
         animator.addAnimations { [weak self] in
             guard let `self` = self else { return }
@@ -633,7 +647,7 @@ class FloatingPanel: NSObject, UIGestureRecognizerDelegate, UIScrollViewDelegate
 
         stopScrollDeceleration = false
         // Don't unlock scroll view in animating view when presentation layer != model layer
-        if targetPosition == .full {
+        if state == layoutAdapter.topMostState {
             unlockScrollView()
         }
     }
@@ -646,11 +660,11 @@ class FloatingPanel: NSObject, UIGestureRecognizerDelegate, UIScrollViewDelegate
 
         switch targetPosition {
         case .full:
-            return CGFloat(fabs(currentY - topY))
+            return CGFloat(abs(currentY - topY))
         case .half:
-            return CGFloat(fabs(currentY - middleY))
+            return CGFloat(abs(currentY - middleY))
         case .tip:
-            return CGFloat(fabs(currentY - bottomY))
+            return CGFloat(abs(currentY - bottomY))
         case .hidden:
             fatalError("Now .hidden must not be used for a user interaction")
         }
@@ -689,7 +703,7 @@ class FloatingPanel: NSObject, UIGestureRecognizerDelegate, UIScrollViewDelegate
 
     // Distance travelled after decelerating to zero velocity at a constant rate.
     // Refer to the slides p176 of [Designing Fluid Interfaces](https://developer.apple.com/videos/play/wwdc2018/803/)
-    private func project(initialVelocity: CGFloat, decelerationRate: CGFloat = UIScrollViewDecelerationRateNormal) -> CGFloat {
+    private func project(initialVelocity: CGFloat, decelerationRate: CGFloat) -> CGFloat {
         return (initialVelocity / 1000.0) * decelerationRate / (1.0 - decelerationRate)
     }
 
@@ -869,8 +883,9 @@ class FloatingPanel: NSObject, UIGestureRecognizerDelegate, UIScrollViewDelegate
 
     private func settle(scrollView: UIScrollView) {
         log.debug("settle scroll view")
-
+        let frame = surfaceView.layer.presentation()?.frame ?? surfaceView.frame
         surfaceView.transform = .identity
+        surfaceView.frame = frame
         scrollView.transform = .identity
         scrollView.frame = initialScrollFrame
         scrollView.contentOffset = scrollView.contentOffsetZero
@@ -878,36 +893,14 @@ class FloatingPanel: NSObject, UIGestureRecognizerDelegate, UIScrollViewDelegate
     }
 
 
-    // MARK: - UIScrollViewDelegate Intermediation
-    override func responds(to aSelector: Selector!) -> Bool {
-        return super.responds(to: aSelector) || userScrollViewDelegate?.responds(to: aSelector) == true
-    }
-
-    override func forwardingTarget(for aSelector: Selector!) -> Any? {
-        if userScrollViewDelegate?.responds(to: aSelector) == true {
-            return userScrollViewDelegate
-        } else {
-            return super.forwardingTarget(for: aSelector)
-        }
-    }
-
-    func scrollViewWillEndDragging(_ scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer<CGPoint>) {
-        if stopScrollDeceleration {
-            targetContentOffset.pointee = scrollView.contentOffset
-            stopScrollDeceleration = false
-        } else {
-            let targetOffset = targetContentOffset.pointee
-            userScrollViewDelegate?.scrollViewWillEndDragging?(scrollView, withVelocity: velocity, targetContentOffset: targetContentOffset)
-            // Stop scrolling on tip and half
-            if state != .full, targetOffset == targetContentOffset.pointee {
-                targetContentOffset.pointee.y = scrollView.contentOffset.y
-            }
-        }
+    private func stopScrollingWithDeceleration(at contentOffset: CGPoint) {
+        // Must use setContentOffset(_:animated) to force-stop deceleration
+        scrollView?.setContentOffset(contentOffset, animated: false)
     }
 }
 
 class FloatingPanelPanGestureRecognizer: UIPanGestureRecognizer {
-    fileprivate var floatingPanel: FloatingPanel?
+    fileprivate weak var floatingPanel: FloatingPanel?
     override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent) {
         super.touchesBegan(touches, with: event)
         if floatingPanel?.animator != nil {

Framework/Sources/FloatingPanelBehavior.swift

@@ -72,14 +72,18 @@ public extension FloatingPanelBehavior {
     }
 
     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
     }
 
-    public func interactionAnimator(_ fpc: FloatingPanelController, to targetPosition: FloatingPanelPosition, with velocity: CGVector) -> UIViewPropertyAnimator {
+    func interactionAnimator(_ fpc: FloatingPanelController, to targetPosition: FloatingPanelPosition, with velocity: CGVector) -> UIViewPropertyAnimator {
         return defaultBehavior.interactionAnimator(fpc, to: targetPosition, with: velocity)
     }
 

Framework/Sources/FloatingPanelController.swift

@@ -146,6 +146,7 @@ public class FloatingPanelController: UIViewController, UIScrollViewDelegate, UI
     private var _contentViewController: UIViewController?
 
     private var floatingPanel: FloatingPanel!
+    private var preSafeAreaInsets: UIEdgeInsets = .zero // Capture the latest one
     private var safeAreaInsetsObservation: NSKeyValueObservation?
     private let modalTransition = FloatingPanelModalTransition()
 
@@ -200,7 +201,9 @@ public class FloatingPanelController: UIViewController, UIScrollViewDelegate, UI
         if #available(iOS 11.0, *) {}
         else {
             // Because {top,bottom}LayoutGuide is managed as a view
-            self.update(safeAreaInsets: layoutInsets)
+            if preSafeAreaInsets != layoutInsets {
+                self.update(safeAreaInsets: layoutInsets)
+            }
         }
     }
 
@@ -245,13 +248,14 @@ public class FloatingPanelController: UIViewController, UIScrollViewDelegate, UI
 
     private func update(safeAreaInsets: UIEdgeInsets) {
         guard
-            floatingPanel.layoutAdapter.safeAreaInsets != safeAreaInsets,
+            preSafeAreaInsets != safeAreaInsets,
             self.floatingPanel.isDecelerating == false
             else { return }
 
         log.debug("Update safeAreaInsets", safeAreaInsets)
 
-        floatingPanel.layoutAdapter.safeAreaInsets = safeAreaInsets
+        // Prevent an infinite loop on iOS 10: setUpLayout() -> viewDidLayoutSubviews() -> setUpLayout()
+        preSafeAreaInsets = safeAreaInsets
 
         setUpLayout()
 
@@ -267,6 +271,15 @@ public class FloatingPanelController: UIViewController, UIScrollViewDelegate, UI
     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 setUpLayout() {
@@ -294,9 +307,9 @@ public class FloatingPanelController: UIViewController, UIScrollViewDelegate, UI
             // inset's update expectedly.
             // 2. The safe area top inset can be variable on the large title navigation bar(iOS11+).
             // That's why it needs the observation to keep `adjustedContentInsets` correct.
-            safeAreaInsetsObservation = self.observe(\.view.safeAreaInsets) { [weak self] (vc, chaneg) in
-                guard let `self` = self else { return }
-                self.update(safeAreaInsets: vc.layoutInsets)
+            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.
@@ -338,7 +351,11 @@ public class FloatingPanelController: UIViewController, UIScrollViewDelegate, UI
             parent.view.addSubview(self.view)
         }
 
+        #if swift(>=4.2)
+        parent.addChild(self)
+        #else
         parent.addChildViewController(self)
+        #endif
 
         view.frame = parent.view.bounds // Needed for a correct safe area configuration
         view.translatesAutoresizingMaskIntoConstraints = false
@@ -351,7 +368,11 @@ public class FloatingPanelController: UIViewController, UIScrollViewDelegate, UI
 
         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
         }
     }
 
@@ -367,9 +388,20 @@ public class FloatingPanelController: UIViewController, UIScrollViewDelegate, UI
 
         hide(animated: animated) { [weak self] in
             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?()
         }
     }
@@ -384,25 +416,39 @@ 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)
-            vc.view.removeFromSuperview()
-            vc.removeFromParentViewController()
+            #endif
 
-            if let scrollView = floatingPanel.scrollView,
-                let delegate = floatingPanel.userScrollViewDelegate,
-                vc.view.subviews.contains(scrollView) {
-                scrollView.delegate = delegate
-            }
+            vc.view.removeFromSuperview()
+
+            #if swift(>=4.2)
+            vc.removeFromParent()
+            #else
+            vc.removeFromParentViewController()
+            #endif
         }
 
         if let vc = contentViewController {
+            #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
@@ -428,33 +474,28 @@ public class FloatingPanelController: UIViewController, UIScrollViewDelegate, UI
     ///
     /// - Parameters:
     ///     - scrollView: Specify a scroll view to continuously and seamlessly work in concert with interactions of the surface view or nil to cancel it.
-    /// - 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?) {
-        if let trackingScrollView = floatingPanel.scrollView,
-            let delegate = floatingPanel.userScrollViewDelegate {
-            trackingScrollView.delegate = delegate // restore delegate
-            floatingPanel.userScrollViewDelegate = nil
-        }
-
         guard let scrollView = scrollView else {
             floatingPanel.scrollView = nil
             return
         }
 
         floatingPanel.scrollView = scrollView
-        if scrollView.delegate !== floatingPanel {
-            floatingPanel.userScrollViewDelegate = scrollView.delegate
-            scrollView.delegate = floatingPanel
-        }
+
         switch contentInsetAdjustmentBehavior {
         case .always:
             if #available(iOS 11.0, *) {
                 scrollView.contentInsetAdjustmentBehavior = .never
             } else {
+                #if swift(>=4.2)
+                children.forEach { (vc) in
+                    vc.automaticallyAdjustsScrollViewInsets = false
+                }
+                #else
                 childViewControllers.forEach { (vc) in
                     vc.automaticallyAdjustsScrollViewInsets = false
                 }
+                #endif
             }
         default:
             break
@@ -475,7 +516,7 @@ public class FloatingPanelController: UIViewController, UIScrollViewDelegate, UI
         setUpLayout()
     }
 
-    /// 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:
@@ -508,10 +549,10 @@ 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) {
+    @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 {

Framework/Sources/FloatingPanelLayout.swift

@@ -142,7 +142,9 @@ class FloatingPanelLayoutAdapter {
         }
     }
 
-    var safeAreaInsets: UIEdgeInsets = .zero
+    private var safeAreaInsets: UIEdgeInsets {
+        return vc?.layoutInsets ?? .zero
+    }
 
     private var initialConst: CGFloat = 0.0
 
@@ -178,6 +180,16 @@ class FloatingPanelLayoutAdapter {
         return supportedPositions
     }
 
+    var topMostState: FloatingPanelPosition {
+        if supportedPositions.contains(.full) {
+            return .full
+        }
+        if supportedPositions.contains(.half) {
+            return .half
+        }
+        return .tip
+    }
+
     var topY: CGFloat {
         if supportedPositions.contains(.full) {
             switch layout {
@@ -258,7 +270,11 @@ class FloatingPanelLayoutAdapter {
     }
 
     func updateIntrinsicHeight() {
+        #if swift(>=4.2)
+        let fittingSize = UIView.layoutFittingCompressedSize
+        #else
         let fittingSize = UILayoutFittingCompressedSize
+        #endif
         var intrinsicHeight = surfaceView.contentView?.systemLayoutSizeFitting(fittingSize).height ?? 0.0
         var safeAreaBottom: CGFloat = 0.0
         if #available(iOS 11.0, *) {
@@ -376,12 +392,10 @@ class FloatingPanelLayoutAdapter {
         case is FloatingPanelIntrinsicLayout:
             updateIntrinsicHeight()
             heightConstraint = surfaceView.heightAnchor.constraint(equalToConstant: intrinsicHeight + safeAreaInsets.bottom)
-        case is FloatingPanelFullScreenLayout:
-            heightConstraint =  surfaceView.heightAnchor.constraint(equalTo: vc.view.heightAnchor,
-                                                                    constant: -fullInset)
         default:
-            heightConstraint = surfaceView.heightAnchor.constraint(equalTo: vc.view.heightAnchor,
-                                                                   constant: -(safeAreaInsets.top + fullInset))
+            let const = -(positionY(for: topMostState))
+            heightConstraint =  surfaceView.heightAnchor.constraint(equalTo: vc.view.heightAnchor,
+                                                                    constant: const)
         }
 
         NSLayoutConstraint.activate([heightConstraint])
@@ -406,10 +420,10 @@ class FloatingPanelLayoutAdapter {
         let minY: CGFloat = {
             var ret: CGFloat = 0.0
             switch layout {
-            case is FloatingPanelIntrinsicLayout:
+            case is FloatingPanelIntrinsicLayout, is FloatingPanelFullScreenLayout:
                 ret = topY
             default:
-                ret = fullInset
+                ret = topY - safeAreaInsets.top
             }
             if allowsTopBuffer {
                 ret -= layout.topInteractionBuffer
@@ -476,8 +490,8 @@ class FloatingPanelLayoutAdapter {
     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))")
+        assert(supportedPositions.union([.hidden]).contains(layout.initialPosition),
+               "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")

Framework/Sources/FloatingPanelSurfaceView.swift

@@ -59,7 +59,7 @@ public class FloatingPanelSurfaceView: UIView {
     /// The color of the surface border.
     public var borderWidth: CGFloat = 0.0  { didSet { setNeedsLayout() } }
 
-    private var backgroundView: UIView!
+    public var backgroundView: UIView!
     private var backgroundHeightConstraint: NSLayoutConstraint!
 
     private struct Default {
@@ -126,8 +126,11 @@ public class FloatingPanelSurfaceView: UIView {
 
     private func updateLayers() {
         backgroundView.backgroundColor = color
-        backgroundView.layer.masksToBounds = true
-        backgroundView.layer.cornerRadius = cornerRadius
+
+        if cornerRadius != 0.0, backgroundView.layer.cornerRadius != cornerRadius {
+            backgroundView.layer.masksToBounds = true
+            backgroundView.layer.cornerRadius = cornerRadius
+        }
 
         if shadowHidden == false {
             layer.shadowColor = shadowColor.cgColor
@@ -138,13 +141,19 @@ public class FloatingPanelSurfaceView: UIView {
     }
 
     private func updateContentViewMask() {
+        guard
+            let contentView = contentView,
+            cornerRadius != 0.0,
+            contentView.layer.cornerRadius != cornerRadius
+            else { return }
+
         if #available(iOS 11, *) {
             // Don't use `contentView.clipToBounds` because it prevents content view from expanding the height of a subview of it
             // for the bottom overflow like Auto Layout settings of UIVisualEffectView in Main.storyboard of Example/Maps.
             // Because the bottom of contentView must be fit to the bottom of a screen to work the `safeLayoutGuide` of a content VC.
-            contentView?.layer.masksToBounds = true
-            contentView?.layer.cornerRadius = cornerRadius
-            contentView?.layer.maskedCorners = [.layerMinXMinYCorner, .layerMaxXMinYCorner]
+            contentView.layer.masksToBounds = true
+            contentView.layer.cornerRadius = cornerRadius
+            contentView.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.

Framework/Sources/Info.plist

@@ -15,7 +15,7 @@
 	<key>CFBundlePackageType</key>
 	<string>FMWK</string>
 	<key>CFBundleShortVersionString</key>
-	<string>1.1.0</string>
+	<string>1.5.0</string>
 	<key>CFBundleVersion</key>
 	<string>$(CURRENT_PROJECT_VERSION)</string>
 </dict>

Framework/Sources/Logger.swift

@@ -10,7 +10,6 @@ var log = {
     return Logger()
 }()
 
-#if __FP_LOG
 struct Logger {
     private let osLog: OSLog
     private let s = DispatchSemaphore(value: 1)
@@ -20,29 +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, *)
@@ -50,9 +37,8 @@ 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
             }
         }
 
@@ -70,7 +56,14 @@ struct Logger {
         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)"
+            }
+        }()
 
         os_log("%@", log: osLog, type: level.osLogType, log)
     }
@@ -84,7 +77,9 @@ 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) {
@@ -98,17 +93,4 @@ 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)
-    }
 }
-#else
-struct Logger {
-    func debug(_ log: Any, _ arguments: Any...) { }
-    func info(_ log: Any, _ arguments: Any...) { }
-    func warning(_ log: Any, _ arguments: Any...) { }
-    func error(_ log: Any, _ arguments: Any...) { }
-    func fault(_ log: Any, _ arguments: Any...) { }
-}
-#endif

Framework/Sources/UIExtensions.swift

@@ -73,7 +73,21 @@ 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"
+        }
+    }
+}
+#else
 extension UIGestureRecognizerState: CustomDebugStringConvertible {
     public var debugDescription: String {
         switch self {
@@ -86,6 +100,8 @@ extension UIGestureRecognizerState: CustomDebugStringConvertible {
         }
     }
 }
+#endif
+#endif
 
 extension UIScrollView {
     var contentOffsetZero: CGPoint {

Framework/Tests/FloatingPanelTests.swift

@@ -0,0 +1,47 @@
+//
+//  Created by Shin Yamamoto on 2018/09/18.
+//  Copyright © 2018 Shin Yamamoto. All rights reserved.
+//
+
+import XCTest
+@testable import FloatingPanel
+
+class ViewTests: XCTestCase {
+
+    override func setUp() {}
+
+    override func tearDown() {}
+
+    func test_WarningRetainCycle() {
+        let myVC = MyZombieViewController(nibName: nil, bundle: nil)
+        myVC.loadViewIfNeeded()
+        // Check if there are memory leak warnings in console logs
+    }
+}
+
+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/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() {}
-}

README.md

@@ -4,6 +4,7 @@
 [![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