Version 2.6.4

The Logging API document says that `os_log` is one of the legacy logging
symbols. However,  this library needs to be supported below iOS 14 so
`log(level:_:)` cannot be used.

.github/workflows/ci.yml

@@ -17,6 +17,9 @@ jobs:
       fail-fast: false
       matrix:
         include:
+          - swift: "5.8"
+            xcode: "14.3"
+            runsOn: macos-13
           - swift: "5.7"
             xcode: "14.1"
             runsOn: macos-12
@@ -48,10 +51,10 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - os: "16.1"
-            xcode: "14.1"
+          - os: "16.4"
+            xcode: "14.3.1"
             sim: "iPhone 14 Pro"
-            runsOn: macos-12
+            runsOn: macos-13
           - os: "15.5"
             xcode: "13.4.1"
             sim: "iPhone 13 Pro"

.spi.yml

@@ -0,0 +1,5 @@
+version: 1
+builder:
+  configs:
+    - documentation_targets: [FloatingPanel]
+      platform: ios

Examples/Samples/Sources/ContentViewControllers/DebugTableViewController.swift

@@ -151,7 +151,7 @@ class DebugTableViewController: InspectableViewController {
             }
         }
         // Set titles
-        tracksScrollView = false
+        tracksScrollView = true
         followsScrollViewBouncing = false
     }
 

Examples/Samples/Sources/UseCases/UseCase.swift

@@ -10,6 +10,7 @@ enum UseCase: Int, CaseIterable {
     case showPanelModal
     case showMultiPanelModal
     case showPanelInSheetModal
+    case showOnWindow
     case showTabBar
     case showPageView
     case showPageContentView
@@ -34,6 +35,7 @@ extension UseCase {
         case .showModal: return "Show Modal"
         case .showPanelModal: return "Show Panel Modal"
         case .showMultiPanelModal: return "Show Multi Panel Modal"
+        case .showOnWindow: return "Show Panel over Window"
         case .showPanelInSheetModal: return "Show Panel in Sheet Modal"
         case .showTabBar: return "Show Tab Bar"
         case .showPageView: return "Show Page View"
@@ -65,6 +67,7 @@ extension UseCase {
         case .showDetail: return .storyboard(String(describing: DetailViewController.self))
         case .showModal: return .storyboard(String(describing: ModalViewController.self))
         case .showMultiPanelModal: return .viewController(DebugTableViewController())
+        case .showOnWindow: return .viewController(DebugTableViewController())
         case .showPanelInSheetModal: return .viewController(DebugTableViewController())
         case .showPanelModal: return .viewController(DebugTableViewController())
         case .showTabBar: return .storyboard(String(describing: TabBarViewController.self))

Examples/Samples/Sources/UseCases/UseCaseController.swift

@@ -11,6 +11,7 @@ final class UseCaseController: NSObject {
     private var detailPanelVC: FloatingPanelController!
     private var settingsPanelVC: FloatingPanelController!
     private lazy var pagePanelController = PagePanelController()
+    private lazy var overWindowPanelVC = FloatingPanelController()
 
     init(mainVC: MainViewController) {
         self.mainVC = mainVC
@@ -157,6 +158,19 @@ extension UseCaseController {
             let fpc = MultiPanelController()
             mainVC.present(fpc, animated: true, completion: nil)
 
+        case .showOnWindow:
+            let fpc = overWindowPanelVC
+            fpc.backdropView.dismissalTapGestureRecognizer.isEnabled = true
+            fpc.set(contentViewController: contentVC)
+            fpc.ext_trackScrollView(in: contentVC)
+
+            guard let window = UIApplication.shared.windows.first else { fatalError("Any window not found") }
+
+            window.addSubview(fpc.view)
+            fpc.view.frame = window.bounds
+            fpc.view.autoresizingMask = [.flexibleWidth, .flexibleHeight]
+
+            fpc.show(animated: true)
         case .showPanelInSheetModal:
             let fpc = FloatingPanelController()
             let contentVC = UIViewController()

FloatingPanel.podspec

@@ -1,7 +1,7 @@
 Pod::Spec.new do |s|
 
   s.name                = "FloatingPanel"
-  s.version             = "2.6.2"
+  s.version             = "2.6.4"
   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.

FloatingPanel.xcodeproj/project.pbxproj

@@ -25,7 +25,7 @@
 		549E944522CF295D0050AECF /* StateTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 549E944422CF295D0050AECF /* StateTests.swift */; };
 		54A6B6B122968B530077F348 /* CoreTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54A6B6B022968B530077F348 /* CoreTests.swift */; };
 		54A6B6B82296A8520077F348 /* SurfaceViewTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54A6B6B72296A8520077F348 /* SurfaceViewTests.swift */; };
-		54ABD7AF216CCFF7002E6C13 /* Logger.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54ABD7AE216CCFF7002E6C13 /* Logger.swift */; };
+		54ABD7AF216CCFF7002E6C13 /* Logging.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54ABD7AE216CCFF7002E6C13 /* Logging.swift */; };
 		54CDC5D3215B6D5A007D205C /* SurfaceView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54CDC5D2215B6D5A007D205C /* SurfaceView.swift */; };
 		54CDC5D5215B6D8D007D205C /* BackdropView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54CDC5D4215B6D8D007D205C /* BackdropView.swift */; };
 		54CFBFC3215CD045006B5735 /* Layout.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54CFBFC2215CD045006B5735 /* Layout.swift */; };
@@ -67,7 +67,7 @@
 		549E944422CF295D0050AECF /* StateTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = StateTests.swift; sourceTree = "<group>"; };
 		54A6B6B022968B530077F348 /* CoreTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CoreTests.swift; sourceTree = "<group>"; };
 		54A6B6B72296A8520077F348 /* SurfaceViewTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SurfaceViewTests.swift; sourceTree = "<group>"; };
-		54ABD7AE216CCFF7002E6C13 /* Logger.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Logger.swift; sourceTree = "<group>"; };
+		54ABD7AE216CCFF7002E6C13 /* Logging.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Logging.swift; sourceTree = "<group>"; };
 		54CDC5D2215B6D5A007D205C /* SurfaceView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SurfaceView.swift; sourceTree = "<group>"; };
 		54CDC5D4215B6D8D007D205C /* BackdropView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BackdropView.swift; sourceTree = "<group>"; };
 		54CFBFC2215CD045006B5735 /* Layout.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Layout.swift; sourceTree = "<group>"; };
@@ -133,7 +133,7 @@
 				545DBA2A2152383100CA77B8 /* GrabberView.swift */,
 				54352E9521A51A2500CBCA08 /* Transitioning.swift */,
 				54DBA3DB262E938500D75969 /* Extensions.swift */,
-				54ABD7AE216CCFF7002E6C13 /* Logger.swift */,
+				54ABD7AE216CCFF7002E6C13 /* Logging.swift */,
 				545DB9C42151169500CA77B8 /* FloatingPanel.h */,
 				545DB9C52151169500CA77B8 /* Info.plist */,
 				54E3992627141F5100A8F9ED /* FloatingPanel.docc */,
@@ -282,7 +282,7 @@
 				54CDC5D5215B6D8D007D205C /* BackdropView.swift in Sources */,
 				54352E9821A521CA00CBCA08 /* PassthroughView.swift in Sources */,
 				54CFBFC5215CD09C006B5735 /* Core.swift in Sources */,
-				54ABD7AF216CCFF7002E6C13 /* Logger.swift in Sources */,
+				54ABD7AF216CCFF7002E6C13 /* Logging.swift in Sources */,
 				545DB9E021511AC100CA77B8 /* Controller.swift in Sources */,
 				54DBA3DC262E938500D75969 /* Extensions.swift in Sources */,
 				5450EEE421646DF500135936 /* Behavior.swift in Sources */,

README.md

@@ -9,7 +9,7 @@
 FloatingPanel is a simple and easy-to-use UI component designed for a user interface featured in Apple Maps, Shortcuts and Stocks app.
 The user interface displays related content and utilities alongside the main content.
 
-Please see also [the API reference](https://floatingpanel.github.io/2.6.2/documentation/floatingpanel/) for more details, powered by [DocC](https://developer.apple.com/documentation/docc).
+Please see also [the API reference](https://floatingpanel.github.io/2.6.4/documentation/floatingpanel/) for more details.
 
 ![Maps](https://github.com/SCENEE/FloatingPanel/blob/master/assets/maps.gif)
 ![Stocks](https://github.com/SCENEE/FloatingPanel/blob/master/assets/stocks.gif)

Sources/Controller.swift

@@ -1,6 +1,7 @@
 // Copyright 2018-Present Shin Yamamoto. All rights reserved. MIT license.
 
 import UIKit
+import os.log
 
 /// A set of methods implemented by the delegate of a panel controller allows the adopting delegate to respond to
 /// messages from the FloatingPanelController class and thus respond to, and in some affect, operations such as
@@ -167,7 +168,8 @@ open class FloatingPanelController: UIViewController {
         set {
             _layout = newValue
             if let parent = parent, let layout = newValue as? UIViewController, layout == parent {
-                log.warning("A memory leak will occur by a retain cycle because \(self) owns the parent view controller(\(parent)) as the layout object. Don't let the parent adopt FloatingPanelLayout.")
+                let log = "Warning: A memory leak occurs due to a retain cycle, as \(self) owns the parent view controller(\(parent)) as its layout object. Don't allow the parent to adopt FloatingPanelLayout."
+                os_log(msg, log: sysLog, type: .error, log)
             }
         }
     }
@@ -179,7 +181,8 @@ open class FloatingPanelController: UIViewController {
         set {
             _behavior = newValue
             if let parent = parent, let behavior = newValue as? UIViewController, behavior == parent {
-                log.warning("A memory leak will occur by a retain cycle because \(self) owns the parent view controller(\(parent)) as the behavior object. Don't let the parent adopt FloatingPanelBehavior.")
+                let log = "Warning: A memory leak occurs due to a retain cycle, as \(self) owns the parent view controller(\(parent)) as its behavior object. Don't allow the parent to adopt FloatingPanelBehavior."
+                os_log(msg, log: sysLog, type: .error, log)
             }
         }
     }
@@ -375,7 +378,7 @@ open class FloatingPanelController: UIViewController {
             preSafeAreaInsets != safeAreaInsets
             else { return }
 
-        log.debug("Update safeAreaInsets", safeAreaInsets)
+        os_log(msg, log: devLog, type: .debug, "Update safeAreaInsets = \(safeAreaInsets)")
 
         // Prevent an infinite loop on iOS 10: setUpLayout() -> viewDidLayoutSubviews() -> setUpLayout()
         preSafeAreaInsets = safeAreaInsets
@@ -414,8 +417,14 @@ open class FloatingPanelController: UIViewController {
                 guard let self = self else { return }
                 self.delegate?.floatingPanelDidRemove?(self)
             }
-        } else {
+        } else if parent != nil {
             removePanelFromParent(animated: true)
+        } else {
+            hide(animated: true) { [weak self] in
+                guard let self = self else { return }
+                self.view.removeFromSuperview()
+                self.delegate?.floatingPanelDidRemove?(self)
+            }
         }
     }
 
@@ -476,7 +485,7 @@ open class FloatingPanelController: UIViewController {
     @objc(addPanelToParent:at:animated:completion:)
     public func addPanel(toParent parent: UIViewController, at viewIndex: Int = -1, animated: Bool = false, completion: (() -> Void)? = nil) {
         guard self.parent == nil else {
-            log.warning("Already added to a parent(\(parent))")
+            os_log(msg, log: sysLog, type: .error, "Warning: already added to a parent(\(parent))")
             return
         }
         assert((parent is UINavigationController) == false, "UINavigationController displays only one child view controller at a time.")
@@ -692,30 +701,30 @@ extension FloatingPanelController {
     }
 }
 
+// MARK: - Swizzling
+
+private var originalDismissImp: IMP?
+private typealias DismissFunction = @convention(c) (AnyObject, Selector, Bool, (() -> Void)?) -> Void
 extension FloatingPanelController {
     private static let dismissSwizzling: Void = {
         let aClass: AnyClass! = UIViewController.self //object_getClass(vc)
-        if let imp = class_getMethodImplementation(aClass, #selector(dismiss(animated:completion:))),
-            let originalAltMethod = class_getInstanceMethod(aClass, #selector(fp_original_dismiss(animated:completion:))) {
-            method_setImplementation(originalAltMethod, imp)
-        }
-        let originalMethod = class_getInstanceMethod(aClass, #selector(dismiss(animated:completion:)))
-        let swizzledMethod = class_getInstanceMethod(aClass, #selector(fp_dismiss(animated:completion:)))
-        if let originalMethod = originalMethod, let swizzledMethod = swizzledMethod {
-            method_exchangeImplementations(originalMethod, swizzledMethod)
+        if let originalMethod = class_getInstanceMethod(aClass, #selector(dismiss(animated:completion:))),
+           let swizzledImp = class_getMethodImplementation(aClass, #selector(__swizzled_dismiss(animated:completion:))) {
+           originalDismissImp = method_setImplementation(originalMethod, swizzledImp)
         }
     }()
 }
 
-public extension UIViewController {
-    @objc func fp_original_dismiss(animated flag: Bool, completion: (() -> Void)? = nil) {
-        // Implementation will be replaced by IMP of self.dismiss(animated:completion:)
-    }
-    @objc func fp_dismiss(animated flag: Bool, completion: (() -> Void)? = nil) {
+extension UIViewController {
+    @objc
+    fileprivate func __swizzled_dismiss(animated flag: Bool, completion: (() -> Void)? = nil) {
+        let dismissImp = unsafeBitCast(originalDismissImp, to: DismissFunction.self)
+        let sel = #selector(UIViewController.dismiss(animated:completion:))
+
         // 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)
+                dismissImp(self, sel, flag, completion)
             } else {
                 fpc.removePanelFromParent(animated: flag, completion: completion)
             }
@@ -725,7 +734,7 @@ public extension UIViewController {
         if let fpc = self as? FloatingPanelController {
             // When a panel is presented modally and it's not a child view controller of the presented view controller.
             if fpc.presentingViewController != nil, fpc.parent == nil {
-                self.fp_original_dismiss(animated: flag, completion: completion)
+                dismissImp(self, sel, flag, completion)
             } else {
                 fpc.removePanelFromParent(animated: flag, completion: completion)
             }
@@ -733,6 +742,6 @@ public extension UIViewController {
         }
 
         // For other view controllers
-        self.fp_original_dismiss(animated: flag, completion: completion)
+        dismissImp(self, sel, flag, completion)
     }
 }

Sources/Core.swift

@@ -1,6 +1,7 @@
 // Copyright 2018-Present Shin Yamamoto. All rights reserved. MIT license.
 
 import UIKit
+import os.log
 
 ///
 /// The presentation model of FloatingPanel
@@ -20,11 +21,13 @@ class Core: NSObject, UIGestureRecognizerDelegate {
             if let cur = scrollView {
                 if oldValue == nil {
                     initialScrollOffset = cur.contentOffset
+                    scrollBounce = cur.bounces
                     scrollIndictorVisible = cur.showsVerticalScrollIndicator
                 }
             } else {
                 if let pre = oldValue {
                     pre.isDirectionalLockEnabled = false
+                    pre.bounces = scrollBounce
                     pre.showsVerticalScrollIndicator = scrollIndictorVisible
                 }
             }
@@ -33,7 +36,7 @@ class Core: NSObject, UIGestureRecognizerDelegate {
 
     private(set) var state: FloatingPanelState = .hidden {
         didSet {
-            log.debug("state changed: \(oldValue) -> \(state)")
+            os_log(msg, log: devLog, type: .debug, "state changed: \(oldValue) -> \(state)")
             if let vc = ownerVC {
                 vc.delegate?.floatingPanelDidChangeState?(vc)
             }
@@ -62,7 +65,9 @@ class Core: NSObject, UIGestureRecognizerDelegate {
     // Scroll handling
     private var initialScrollOffset: CGPoint = .zero
     private var stopScrollDeceleration: Bool = false
+    private var scrollBounce = false
     private var scrollIndictorVisible = false
+    private var scrollBounceThreshold: CGFloat = -30.0
 
     // MARK: - Interface
 
@@ -159,7 +164,7 @@ class Core: NSObject, UIGestureRecognizerDelegate {
                 self.updateLayout(to: to)
 
                 if shouldDoubleLayout {
-                    log.info("Lay out the surface again to modify an intrinsic size error according to UIStackView")
+                    os_log(msg, log: sysLog, type: .info, "Lay out the surface again to modify an intrinsic size error according to UIStackView")
                     self.updateLayout(to: to)
                 }
             }
@@ -228,7 +233,7 @@ class Core: NSObject, UIGestureRecognizerDelegate {
     }
 
     func getBackdropAlpha(at cur: CGFloat, with translation: CGFloat) -> CGFloat {
-        /* log.debug("currentY: \(currentY) translation: \(translation)") */
+        /* os_log(msg, log: devLog, type: .debug, "currentY: \(currentY) translation: \(translation)") */
         let forwardY = (translation >= 0)
 
         let segment = layoutAdapter.segment(at: cur, forward: forwardY)
@@ -261,7 +266,7 @@ class Core: NSObject, UIGestureRecognizerDelegate {
 
         guard gestureRecognizer == panGestureRecognizer else { return false }
 
-        /* log.debug("shouldRecognizeSimultaneouslyWith", otherGestureRecognizer) */
+        /* os_log(msg, log: devLog, type: .debug, "shouldRecognizeSimultaneouslyWith", otherGestureRecognizer) */
 
         switch otherGestureRecognizer {
         case is FloatingPanelPanGestureRecognizer:
@@ -334,7 +339,10 @@ class Core: NSObject, UIGestureRecognizerDelegate {
                     if surfaceView.grabberAreaContains(gestureRecognizer.location(in: surfaceView)) {
                         return false
                     }
-                    return allowScrollPanGesture(for: scrollView)
+                    guard state == layoutAdapter.mostExpandedState else { return false }
+                    // The condition where offset > 0 must not be included here. Because it will stop recognizing
+                    // the panel pan gesture if a user starts scrolling content from an offset greater than 0.
+                    return allowScrollPanGesture(of: scrollView) { offset in offset <= scrollBounceThreshold  }
                 default:
                     return false
                 }
@@ -387,13 +395,14 @@ class Core: NSObject, UIGestureRecognizerDelegate {
 
             let insideMostExpandedAnchor = 0 > layoutAdapter.offsetFromMostExpandedAnchor + (1.0 / surfaceView.fp_displayScale)
 
-            log.debug("""
+            os_log(msg, log: devLog, type: .debug, """
                 scroll gesture(\(state):\(panGesture.state)) -- \
                 inside expanded anchor = \(insideMostExpandedAnchor), \
                 interactionInProgress = \(interactionInProgress), \
                 scroll offset = \(value(of: scrollView.contentOffset)), \
                 location = \(value(of: location)), velocity = \(velocity)
-                """)
+                """
+            )
 
             let offsetDiff = value(of: scrollView.contentOffset - contentOffsetForPinning(of: scrollView))
 
@@ -401,7 +410,7 @@ class Core: NSObject, UIGestureRecognizerDelegate {
                 // Scroll offset pinning
                 if state == layoutAdapter.mostExpandedState {
                     if interactionInProgress {
-                        log.debug("settle offset --", value(of: initialScrollOffset))
+                        os_log(msg, log: devLog, type: .debug, "settle offset -- \(value(of: initialScrollOffset))")
                         stopScrolling(at: initialScrollOffset)
                     } else {
                         if surfaceView.grabberAreaContains(location) {
@@ -453,21 +462,24 @@ class Core: NSObject, UIGestureRecognizerDelegate {
                     }
                 } else {
                     if state == layoutAdapter.mostExpandedState {
+                        let allowScroll = allowScrollPanGesture(of: scrollView) { offset in
+                            offset <= scrollBounceThreshold || 0 < offset
+                        }
                         switch layoutAdapter.position {
                         case .top, .left:
-                            if velocity < 0, !allowScrollPanGesture(for: scrollView) {
-                                lockScrollView()
+                            if velocity < 0, !allowScroll {
+                                lockScrollView(strict: true)
                             }
-                            if velocity > 0, allowScrollPanGesture(for: scrollView) {
+                            if velocity > 0, allowScroll {
                                 unlockScrollView()
                             }
                         case .bottom, .right:
                             // Hide a scroll indicator just before starting an interaction by swiping a panel down.
-                            if velocity > 0, !allowScrollPanGesture(for: scrollView) {
-                                lockScrollView()
+                            if velocity > 0, !allowScroll {
+                                lockScrollView(strict: true)
                             }
                             // Show a scroll indicator when an animation is interrupted at the top and content is scrolled up
-                            if velocity < 0, allowScrollPanGesture(for: scrollView) {
+                            if velocity < 0, allowScroll {
                                 unlockScrollView()
                             }
                         }
@@ -483,7 +495,7 @@ class Core: NSObject, UIGestureRecognizerDelegate {
             let velocity = panGesture.velocity(in: panGesture.view)
             let location = panGesture.location(in: panGesture.view)
 
-            log.debug("""
+            os_log(msg, log: devLog, type: .debug, """
                 panel gesture(\(state):\(panGesture.state)) -- \
                 translation =  \(value(of: translation)), \
                 location = \(value(of: location)), \
@@ -533,13 +545,13 @@ class Core: NSObject, UIGestureRecognizerDelegate {
 
     private func interruptAnimationIfNeeded() {
         if let animator = self.moveAnimator, animator.isRunning {
-            log.debug("the attraction animator interrupted!!!")
+            os_log(msg, log: devLog, type: .debug, "the attraction animator interrupted!!!")
             animator.stopAnimation(true)
             endAttraction(false)
         }
         if let animator = self.transitionAnimator {
             guard 0 >= layoutAdapter.offsetFromMostExpandedAnchor else { return }
-            log.debug("a panel animation(interruptible: \(animator.isInterruptible)) interrupted!!!")
+            os_log(msg, log: devLog, type: .debug, "a panel animation(interruptible: \(animator.isInterruptible)) interrupted!!!")
             if animator.isInterruptible {
                 animator.stopAnimation(false)
                 // A user can stop a panel at the nearest Y of a target position so this fine-tunes
@@ -631,7 +643,7 @@ class Core: NSObject, UIGestureRecognizerDelegate {
         // A user interaction does not always start from Began state of the pan gesture
         // because it can be recognized in scrolling a content in a content view controller.
         // So here just preserve the current state if needed.
-        log.debug("panningBegan -- location = \(value(of: location))")
+        os_log(msg, log: devLog, type: .debug, "panningBegan -- location = \(value(of: location))")
 
         guard let scrollView = scrollView else { return }
         if state == layoutAdapter.mostExpandedState {
@@ -644,7 +656,7 @@ class Core: NSObject, UIGestureRecognizerDelegate {
     }
 
     private func panningChange(with translation: CGPoint) {
-        log.debug("panningChange -- translation = \(value(of: translation))")
+        os_log(msg, log: devLog, type: .debug, "panningChange -- translation = \(value(of: translation))")
         let pre = value(of: layoutAdapter.surfaceLocation)
         let diff = value(of: translation - initialTranslation)
         let next = pre + diff
@@ -697,10 +709,10 @@ class Core: NSObject, UIGestureRecognizerDelegate {
     }
 
     private func panningEnd(with translation: CGPoint, velocity: CGPoint) {
-        log.debug("panningEnd -- translation = \(value(of: translation)), velocity = \(value(of: velocity))")
+        os_log(msg, log: devLog, type: .debug, "panningEnd -- translation = \(value(of: translation)), velocity = \(value(of: velocity))")
 
         if state == .hidden {
-            log.debug("Already hidden")
+            os_log(msg, log: devLog, type: .debug, "Already hidden")
             return
         }
 
@@ -789,7 +801,7 @@ class Core: NSObject, UIGestureRecognizerDelegate {
 
     private func startInteraction(with translation: CGPoint, at location: CGPoint) {
         /* Don't lock a scroll view to show a scroll indicator after hitting the top */
-        log.debug("startInteraction  -- translation = \(value(of: translation)), location = \(value(of: location))")
+        os_log(msg, log: devLog, type: .debug, "startInteraction  -- translation = \(value(of: translation)), location = \(value(of: location))")
         guard interactionInProgress == false else { return }
 
         var offset: CGPoint = .zero
@@ -800,13 +812,14 @@ class Core: NSObject, UIGestureRecognizerDelegate {
                 initialScrollOffset = scrollView.contentOffset
             } else {
                 let pinningOffset = contentOffsetForPinning(of: scrollView)
-
-                // `scrollView.contentOffset` can be a value in [-30, 0) at this time by `allowScrollPanGesture(for:)`.
-                // Therefore the initial scroll offset must be reset to the pinning offset. Otherwise, the following
-                // `Fit the surface bounds` logic don't working and also the scroll content offset can be invalid.
+                
+                // `initialScrollOffset` must be reset to the pinning offset because the value of `scrollView.contentOffset`,
+                // for instance, is a value in [-30, 0) on a bottom positioned panel with `allowScrollPanGesture(of:condition:)`.
+                // If it's not reset, the following logic to shift the surface frame will not work and then the scroll
+                // content offset will become an unexpected value.
                 initialScrollOffset = pinningOffset
 
-                // Fit the surface bounds to a scroll offset content by startInteraction(at:offset:)
+                // Shift the surface frame to negate the scroll content offset at startInteraction(at:offset:)
                 let offsetDiff = scrollView.contentOffset - pinningOffset
                 switch layoutAdapter.position {
                 case .top, .left:
@@ -819,7 +832,7 @@ class Core: NSObject, UIGestureRecognizerDelegate {
                     }
                 }
             }
-            log.debug("initial scroll offset --", initialScrollOffset)
+            os_log(msg, log: devLog, type: .debug, "initial scroll offset -- \(initialScrollOffset)")
         }
 
         initialTranslation = translation
@@ -836,10 +849,10 @@ class Core: NSObject, UIGestureRecognizerDelegate {
     }
 
     private func endInteraction(for targetPosition: FloatingPanelState) {
-        log.debug("endInteraction to \(targetPosition)")
+        os_log(msg, log: devLog, type: .debug, "endInteraction to \(targetPosition)")
 
         if let scrollView = scrollView {
-            log.debug("endInteraction -- scroll offset = \(scrollView.contentOffset)")
+            os_log(msg, log: devLog, type: .debug, "endInteraction -- scroll offset = \(scrollView.contentOffset)")
         }
 
         interactionInProgress = false
@@ -867,7 +880,7 @@ class Core: NSObject, UIGestureRecognizerDelegate {
     }
 
     private func startAttraction(to targetPosition: FloatingPanelState, with velocity: CGPoint) {
-        log.debug("startAnimation to \(targetPosition) -- velocity = \(value(of: velocity))")
+        os_log(msg, log: devLog, type: .debug, "startAnimation to \(targetPosition) -- velocity = \(value(of: velocity))")
         guard let vc = ownerVC else { return }
 
         isAttracting = true
@@ -915,18 +928,20 @@ class Core: NSObject, UIGestureRecognizerDelegate {
         }
 
         if let scrollView = scrollView {
-            log.debug("finishAnimation -- scroll offset = \(scrollView.contentOffset)")
+            os_log(msg, log: devLog, type: .debug, "finishAnimation -- scroll offset = \(scrollView.contentOffset)")
         }
 
         stopScrollDeceleration = false
 
-        log.debug("""
+        os_log(msg, log: devLog, type: .debug, """
             finishAnimation -- state = \(state) \
             surface location = \(layoutAdapter.surfaceLocation) \
             edge most position = \(layoutAdapter.surfaceLocation(for: layoutAdapter.mostExpandedState))
             """)
         if finished, state == layoutAdapter.mostExpandedState, abs(layoutAdapter.offsetFromMostExpandedAnchor) <= 1.0 {
             unlockScrollView()
+        } else if finished, shouldLooselyLockScrollView {
+            unlockScrollView()
         }
     }
 
@@ -934,6 +949,10 @@ class Core: NSObject, UIGestureRecognizerDelegate {
         return layoutAdapter.position.mainLocation(point)
     }
 
+    func value(of size: CGSize) -> CGFloat {
+        return layoutAdapter.position.mainDimension(size)
+    }
+
     func setValue(_ newValue: CGPoint, to point: inout CGPoint) {
         switch layoutAdapter.position {
         case .top, .bottom:
@@ -950,7 +969,7 @@ class Core: NSObject, UIGestureRecognizerDelegate {
     }
 
     func targetPosition(from currentY: CGFloat, with velocity: CGFloat) -> (FloatingPanelState) {
-        log.debug("targetPosition -- currentY = \(currentY), velocity = \(velocity)")
+        os_log(msg, log: devLog, type: .debug, "targetPosition -- currentY = \(currentY), velocity = \(velocity)")
 
         let sortedPositions = layoutAdapter.sortedAnchorStatesByCoordinate
 
@@ -976,7 +995,7 @@ class Core: NSObject, UIGestureRecognizerDelegate {
         (fromPos, toPos) = forwardY ? (lowerPos, upperPos) : (upperPos, lowerPos)
 
         if behaviorAdapter.shouldProjectMomentum(to: toPos) == false {
-            log.debug("targetPosition -- negate projection: distance = \(distance)")
+            os_log(msg, log: devLog, type: .debug, "targetPosition -- negate projection: distance = \(distance)")
             let segment = layoutAdapter.segment(at: currentY, forward: forwardY)
             var (lowerPos, upperPos) = (segment.lower ?? sortedPositions.first!, segment.upper ?? sortedPositions.last!)
             // Equate the segment out of {top,bottom} most state to the {top,bottom} most segment
@@ -1021,36 +1040,60 @@ class Core: NSObject, UIGestureRecognizerDelegate {
         scrollView.transform = CGAffineTransform(translationX: 0, y: contentOffset)
     }
 
-    private func lockScrollView() {
+    private func lockScrollView(strict: Bool = false) {
         guard let scrollView = scrollView else { return }
 
         if scrollView.isLocked {
-            log.debug("Already scroll locked.")
+            os_log(msg, log: devLog, type: .debug, "Already scroll locked.")
             return
         }
-        log.debug("lock scroll view")
+        os_log(msg, log: devLog, type: .debug, "lock scroll view")
 
         scrollIndictorVisible = scrollView.showsVerticalScrollIndicator
 
-        // Must not modify the UIScrollView.bounces property here. If you reset it to unlock the tracking scroll view,
-        // UIScrollView may unexpectedly alter the scroll offset when dealing with small scrollable content.
+        if !strict, shouldLooselyLockScrollView {
+            // Don't change its `bounces` property. If it's changed, it will cause its scroll content offset jump at
+            // the most expanded anchor position while seamlessly scrolling content. This problem only occurs where its
+            // content mode is `.fitToBounds` and the tracking scroll content is smaller than the content view size.
+            // The reason why is because `bounces` prop change leads to the "content frame" change on `.fitToBounds`.
+            // See also https://github.com/scenee/FloatingPanel/issues/524.
+        } else {
+            scrollBounce = scrollView.bounces
+            scrollView.bounces = false
+        }
         scrollView.isDirectionalLockEnabled = true
         scrollView.showsVerticalScrollIndicator = false
     }
 
     private func unlockScrollView() {
         guard let scrollView = scrollView, scrollView.isLocked else { return }
-        log.debug("unlock scroll view")
+        os_log(msg, log: devLog, type: .debug, "unlock scroll view")
 
+        scrollView.bounces = scrollBounce
         scrollView.isDirectionalLockEnabled = false
         scrollView.showsVerticalScrollIndicator = scrollIndictorVisible
     }
 
+    private var shouldLooselyLockScrollView: Bool {
+        var isSmallScrollContentAndFitToBoundsMode: Bool {
+            if ownerVC?.contentMode == .fitToBounds, let scrollView = scrollView,
+               value(of: scrollView.contentSize) < value(of: scrollView.bounds.size) - min(layoutAdapter.offsetFromMostExpandedAnchor, 0) {
+                return true
+            }
+            return false
+        }
+        return isSmallScrollContentAndFitToBoundsMode
+    }
+
     private func stopScrolling(at contentOffset: CGPoint) {
         // Must use setContentOffset(_:animated) to force-stop deceleration
         guard let scrollView = scrollView else { return }
         var offset = scrollView.contentOffset
-        setValue(contentOffset, to: &offset)
+        if contentOffset.y >= 0 {
+            setValue(contentOffset, to: &offset)
+        } else {
+            offset = CGPoint(x: 0, y: 0)
+        }
         scrollView.setContentOffset(offset, animated: false)
     }
 
@@ -1070,16 +1113,15 @@ class Core: NSObject, UIGestureRecognizerDelegate {
         }
     }
 
-    private func allowScrollPanGesture(for scrollView: UIScrollView) -> Bool {
-        guard state == layoutAdapter.mostExpandedState else { return false }
-        var offsetY: CGFloat = 0
+    private func allowScrollPanGesture(of scrollView: UIScrollView, condition: (_ offset: CGFloat) -> Bool) -> Bool {
+        var offset: CGFloat = 0
         switch layoutAdapter.position {
         case .top, .left:
-            offsetY = value(of: scrollView.fp_contentOffsetMax - scrollView.contentOffset)
+            offset = value(of: scrollView.fp_contentOffsetMax - scrollView.contentOffset)
         case .bottom, .right:
-            offsetY = value(of: scrollView.contentOffset - contentOffsetForPinning(of: scrollView))
+            offset = value(of: scrollView.contentOffset - contentOffsetForPinning(of: scrollView))
         }
-        return offsetY <= -30.0 || offsetY > 0
+        return condition(offset)
     }
 
     // MARK: - UIPanGestureRecognizer Intermediation
@@ -1203,7 +1245,7 @@ private class NumericSpringAnimator: NSObject {
         if isRunning {
             return false
         }
-        log.debug("startAnimation --", displayLink)
+        os_log(msg, log: devLog, type: .debug, "startAnimation --", displayLink)
         isRunning = true
         displayLink.add(to: RunLoop.main, forMode: .common)
         return true
@@ -1215,7 +1257,7 @@ private class NumericSpringAnimator: NSObject {
             if locked { lock.unlock() }
         }
 
-        log.debug("stopAnimation --", displayLink)
+        os_log(msg, log: devLog, type: .debug, "stopAnimation --", displayLink)
         isRunning = false
         displayLink.invalidate()
         if withoutFinishing {

Sources/Extensions.swift

@@ -157,7 +157,7 @@ extension UIGestureRecognizer.State: CustomDebugStringConvertible {
 
 extension UIScrollView {
     var isLocked: Bool {
-        return !showsVerticalScrollIndicator && isDirectionalLockEnabled
+        return !showsVerticalScrollIndicator && !bounces &&  isDirectionalLockEnabled
     }
     var fp_contentInset: UIEdgeInsets {
         if #available(iOS 11.0, *) {

Sources/Info.plist

@@ -15,7 +15,7 @@
 	<key>CFBundlePackageType</key>
 	<string>FMWK</string>
 	<key>CFBundleShortVersionString</key>
-	<string>2.6.2</string>
+	<string>2.6.4</string>
 	<key>CFBundleVersion</key>
 	<string>$(CURRENT_PROJECT_VERSION)</string>
 </dict>

Sources/Layout.swift

@@ -1,6 +1,7 @@
 // Copyright 2018-Present Shin Yamamoto. All rights reserved. MIT license.
 
 import UIKit
+import os.log
 
 /// An interface for generating layout information for a panel.
 @objc public protocol FloatingPanelLayout {
@@ -710,7 +711,7 @@ class LayoutAdapter {
 
     func updateInteractiveEdgeConstraint(diff: CGFloat, scrollingContent: Bool, allowsRubberBanding: (UIRectEdge) -> Bool) {
         defer {
-            log.debug("update surface location = \(surfaceLocation)")
+            os_log(msg, log: devLog, type: .debug, "update surface location = \(surfaceLocation)")
         }
 
         let minConst: CGFloat = position(for: leastCoordinateState)
@@ -750,9 +751,9 @@ class LayoutAdapter {
         defer {
             if forceLayout {
                 layoutSurfaceIfNeeded()
-                log.debug("activateLayout for \(state) -- surface.presentation = \(self.surfaceView.presentationFrame) surface.frame = \(self.surfaceView.frame)")
+                os_log(msg, log: devLog, type: .debug, "activateLayout for \(state) -- surface.presentation = \(self.surfaceView.presentationFrame) surface.frame = \(self.surfaceView.frame)")
             } else {
-                log.debug("activateLayout for \(state)")
+                os_log(msg, log: devLog, type: .debug, "activateLayout for \(state)")
             }
         }
 
@@ -787,7 +788,7 @@ class LayoutAdapter {
             if let constraints = stateConstraints[state] {
                 NSLayoutConstraint.activate(constraints)
             } else {
-                log.error("Couldn't find any constraints for \(state)")
+                os_log(msg, log: sysLog, type: .fault, "Error: can not find any constraints for \(state)")
             }
         }
     }

Sources/Logger.swift

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

Sources/Logging.swift

@@ -0,0 +1,17 @@
+// Copyright 2018-Present Shin Yamamoto. All rights reserved. MIT license.
+
+import os.log
+
+let msg = StaticString("%{public}@")
+let sysLog = OSLog(subsystem: Logging.subsystem, category: Logging.category)
+#if FP_LOG
+let devLog = OSLog(subsystem: Logging.subsystem, category: "\(Logging.category):dev")
+#else
+let devLog = OSLog.disabled
+#endif
+
+struct Logging {
+    static let subsystem = "com.scenee.FloatingPanel"
+    static let category = "FloatingPanel"
+    private init() {}
+}

Sources/SurfaceView.swift

@@ -1,6 +1,7 @@
 // Copyright 2018-Present Shin Yamamoto. All rights reserved. MIT license.
 
 import UIKit
+import os.log
 
 /// An object for customizing the appearance of a surface view
 @objc(FloatingPanelSurfaceAppearance)
@@ -318,7 +319,7 @@ public class SurfaceView: UIView {
 
     public override func layoutSubviews() {
         super.layoutSubviews()
-        log.debug("surface view frame = \(frame)")
+        os_log(msg, log: devLog, type: .debug, "surface view frame = \(frame)")
 
         containerView.backgroundColor = appearance.backgroundColor
 

Tests/ControllerTests.swift

@@ -1,5 +1,6 @@
 // Copyright 2018 the FloatingPanel authors. All rights reserved. MIT license.
 
+import OSLog
 import XCTest
 @testable import FloatingPanel
 
@@ -7,19 +8,25 @@ class ControllerTests: XCTestCase {
     override func setUp() {}
     override func tearDown() {}
 
-    func test_warningRetainCycle() {
-        let exp = expectation(description: "Warning retain cycle")
-        exp.expectedFulfillmentCount = 2 // For layout & behavior logs
-        log.hook = {(log, level) in
-            if log.contains("A memory leak will occur by a retain cycle because") {
-                XCTAssert(level == .warning)
-                exp.fulfill()
-            }
+#if swift(>=5.5)  // Avoid the 'No exact matches in call to initializer' build failure for OSLogStore when running this test case on iOS 13.7 using Xcode 12.5.1
+    func test_warningRetainCycle() throws {
+        guard #available(iOS 15.0, *) else {
+            throw XCTSkip("Unsupported iOS version: this test needs iOS 15 or later")
         }
         let myVC = MyZombieViewController(nibName: nil, bundle: nil)
         myVC.loadViewIfNeeded()
-        wait(for: [exp], timeout: 10)
+        let store = try OSLogStore(scope: .currentProcessIdentifier)
+        let found = try store
+            .getEntries(
+                at: store.position(timeIntervalSinceLatestBoot: 0),
+                matching: .init(format: "subsystem == '\(Logging.subsystem)'")
+            )
+            .contains {
+                $0.composedMessage.contains("A memory leak occurs due to a retain cycle, as")
+            }
+        XCTAssertTrue(found)
     }
+#endif
 
     func test_addPanel() {
         let rootVC = UIViewController()
@@ -34,8 +41,13 @@ class ControllerTests: XCTestCase {
         XCTAssertEqual(fpc.surfaceLocation.y, fpc.surfaceLocation(for: .tip).y)
     }
 
-    @available(iOS 12.0, *)
-    func test_updateLayout_willTransition() {
+    func test_updateLayout_willTransition() throws {
+        guard #available(iOS 12, *) else {
+            throw XCTSkip("Unsupported iOS version: this test needs iOS 12 or later")
+        }
+        if #available(iOS 17, *) {
+            throw XCTSkip("Unsupported iOS version: this test doesn't support iOS 17 or later")
+        }
         class MyDelegate: FloatingPanelControllerDelegate {
             func floatingPanel(_ vc: FloatingPanelController, layoutFor newCollection: UITraitCollection) -> FloatingPanelLayout {
                 if newCollection.userInterfaceStyle == .dark {
@@ -318,7 +330,6 @@ class ControllerTests: XCTestCase {
         fpc.move(to: .full, animated: false)
         XCTAssertEqual(fpc.surfaceView.frame.height, fpc.view.bounds.height - fpc.surfaceLocation(for: .full).y)
         fpc.move(to: .half, animated: false)
-        print(1 / fpc.surfaceView.fp_displayScale)
         XCTAssertEqual(fpc.surfaceView.frame.height, fpc.view.bounds.height - fpc.surfaceLocation(for: .half).y)
         fpc.move(to: .tip, animated: false)
         XCTAssertEqual(fpc.surfaceView.frame.height, fpc.view.bounds.height - fpc.surfaceLocation(for: .tip).y)

Tests/CoreTests.swift

@@ -12,22 +12,27 @@ class CoreTests: XCTestCase {
 
         let contentVC1 = UITableViewController(nibName: nil, bundle: nil)
         XCTAssertEqual(contentVC1.tableView.showsVerticalScrollIndicator, true)
+        XCTAssertEqual(contentVC1.tableView.bounces, true)
         fpc.set(contentViewController: contentVC1)
         fpc.track(scrollView: contentVC1.tableView)
         fpc.showForTest()
 
         XCTAssertEqual(fpc.state, .half)
         XCTAssertEqual(contentVC1.tableView.showsVerticalScrollIndicator, false)
+        XCTAssertEqual(contentVC1.tableView.bounces, false)
 
         fpc.move(to: .full, animated: false)
         XCTAssertEqual(contentVC1.tableView.showsVerticalScrollIndicator, true)
+        XCTAssertEqual(contentVC1.tableView.bounces, true)
 
         fpc.move(to: .tip, animated: false)
         XCTAssertEqual(contentVC1.tableView.showsVerticalScrollIndicator, false)
+        XCTAssertEqual(contentVC1.tableView.bounces, false)
 
         let exp1 = expectation(description: "move to full with animation")
         fpc.move(to: .full, animated: true) {
             XCTAssertEqual(contentVC1.tableView.showsVerticalScrollIndicator, true)
+            XCTAssertEqual(contentVC1.tableView.bounces, true)
             exp1.fulfill()
         }
         wait(for: [exp1], timeout: 1.0)
@@ -35,6 +40,7 @@ class CoreTests: XCTestCase {
         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)
@@ -42,11 +48,13 @@ class CoreTests: XCTestCase {
         // Reset the content vc
         let contentVC2 = UITableViewController(nibName: nil, bundle: nil)
         XCTAssertEqual(contentVC2.tableView.showsVerticalScrollIndicator, true)
+        XCTAssertEqual(contentVC2.tableView.bounces, true)
         fpc.set(contentViewController: contentVC2)
         fpc.track(scrollView: contentVC2.tableView)
         fpc.show(animated: false, completion: nil)
         XCTAssertEqual(fpc.state, .half)
         XCTAssertEqual(contentVC2.tableView.showsVerticalScrollIndicator, false)
+        XCTAssertEqual(contentVC2.tableView.bounces, false)
     }
 
     func test_getBackdropAlpha_1positions() {

Tests/LayoutTests.swift

@@ -464,7 +464,6 @@ class LayoutTests: XCTestCase {
                 if #available(iOS 11, *) {
                     XCTAssertEqual(c.secondAnchor, prop.result.secondAnchor, line: UInt(prop.result.0))
                 }
-                print(c)
         }
     }
     func test_layoutAnchor_bottomPosition() {