Version 1.7.6

If a library consumer allows a panel projectable movement with the
FloatingPanelBehavior object, the panel is able to invoke the removal
interaction when the next moving position projected the momentum is
hidden.

.github/ISSUE_TEMPLATE.md

@@ -2,7 +2,7 @@
 >
 > Please remove this line and everything above it before submitting.
 
-### Short description
+### Description
 
 ### Expected behavior
 
@@ -12,16 +12,29 @@
 
 **Code example that reproduces the issue**
 
+
+**How do you display panel(s)?**
+
+* Add as child view controllers
+* Present modally
+
+**How many panels do you displays?**
+
+* 1 
+* 2+
+
 ### Environment
 
 **Library version**
 
 **Installation method**
 
-- [ ] CocoaPods
-- [ ] Carthage
-- [ ] Git submodules
-
+* CocoaPods
+* Carthage
+* Swift Package Manager
+ 
 **iOS version(s)**
 
+
 **Xcode version**
+

.gitignore

@@ -30,6 +30,9 @@ xcuserdata/
 *.dSYM.zip
 *.dSYM
 
+## Swift Package Manager Specific
+.swiftpm/
+
 ## Playgrounds
 timeline.xctimeline
 playground.xcworkspace

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

@@ -27,7 +27,7 @@
                                     <rect key="frame" x="0.0" y="0.0" width="375" height="44"/>
                                     <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                                 </view>
-                                <blurEffect style="light"/>
+                                <blurEffect style="prominent"/>
                             </visualEffectView>
                         </subviews>
                         <color key="backgroundColor" red="1" green="1" blue="1" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
@@ -232,7 +232,7 @@
                                         <constraint firstItem="Zcj-SE-gb8" firstAttribute="leading" secondItem="ED1-gT-FBj" secondAttribute="leading" id="wMb-L2-Z0W"/>
                                     </constraints>
                                 </view>
-                                <blurEffect style="extraLight"/>
+                                <blurEffect style="prominent"/>
                             </visualEffectView>
                         </subviews>
                         <color key="backgroundColor" white="0.0" alpha="0.0" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>

Examples/Maps/Maps/ViewController.swift

@@ -274,12 +274,12 @@ class SearchHeaderView: UIView {
 
 extension UISearchBar {
     func setSearchText(fontSize: CGFloat) {
-        #if swift(>=5.1) // Xcode 11 or later
+        if #available(iOS 13, *) {
             let font = searchTextField.font
             searchTextField.font = font?.withSize(fontSize)
-        #else
+        } else {
             let textField = value(forKey: "_searchField") as! UITextField
             textField.font = textField.font?.withSize(fontSize)
-        #endif
+        }
     }
 }

Examples/Samples/Samples.xcodeproj/project.pbxproj

@@ -294,7 +294,7 @@
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 			shellPath = /bin/sh;
-			shellScript = "/usr/libexec/PlistBuddy -c \"Set :CFBundleVersion $(git rev-parse --abbrev-ref HEAD)($(git rev-parse --short HEAD))\" $SRCROOT/$INFOPLIST_FILE\n";
+			shellScript = "/usr/libexec/PlistBuddy -c \"Set :CFBundleVersion $(git rev-parse --abbrev-ref HEAD)($(git rev-parse --short HEAD))\" \"$SRCROOT/$INFOPLIST_FILE\"\n";
 		};
 /* End PBXShellScriptBuildPhase section */
 

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

@@ -1,11 +1,9 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="14490.70" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" useSafeAreas="YES" colorMatched="YES" initialViewController="RoN-h0-uBD">
-    <device id="retina5_9" orientation="portrait">
-        <adaptation id="fullscreen"/>
-    </device>
+<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="15705" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" useSafeAreas="YES" colorMatched="YES" initialViewController="RoN-h0-uBD">
+    <device id="retina5_9" orientation="portrait" appearance="light"/>
     <dependencies>
         <deployment identifier="iOS"/>
-        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="14490.49"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="15706"/>
         <capability name="Safe area layout guides" minToolsVersion="9.0"/>
         <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
     </dependencies>
@@ -13,7 +11,7 @@
         <!--Navigation Controller-->
         <scene sceneID="Cjh-iX-VQw">
             <objects>
-                <navigationController id="RoN-h0-uBD" sceneMemberID="viewController">
+                <navigationController storyboardIdentifier="RootNavigationController" id="RoN-h0-uBD" sceneMemberID="viewController">
                     <navigationBar key="navigationBar" contentMode="scaleToFill" insetsLayoutMarginsFromSafeArea="NO" largeTitles="YES" id="hNW-5m-Omi">
                         <rect key="frame" x="0.0" y="44" width="375" height="96"/>
                         <autoresizingMask key="autoresizingMask"/>

Examples/Samples/Sources/ViewController.swift

@@ -18,6 +18,8 @@ class SampleListViewController: UIViewController {
         case showDetail
         case showModal
         case showPanelModal
+        case showMultiPanelModal
+        case showPanelInSheetModal
         case showTabBar
         case showPageView
         case showPageContentView
@@ -26,6 +28,7 @@ class SampleListViewController: UIViewController {
         case showIntrinsicView
         case showContentInset
         case showContainerMargins
+        case showNavigationController
 
         var name: String {
             switch self {
@@ -34,6 +37,8 @@ class SampleListViewController: UIViewController {
             case .showDetail: return "Show Detail Panel"
             case .showModal: return "Show Modal"
             case .showPanelModal: return "Show Panel Modal"
+            case .showMultiPanelModal: return "Show Multi Panel Modal"
+            case .showPanelInSheetModal: return "Show Panel in Sheet Modal"
             case .showTabBar: return "Show Tab Bar"
             case .showPageView: return "Show Page View"
             case .showPageContentView: return "Show Page Content View"
@@ -42,6 +47,7 @@ class SampleListViewController: UIViewController {
             case .showIntrinsicView: return "Show Intrinsic View"
             case .showContentInset: return "Show with ContentInset"
             case .showContainerMargins: return "Show with ContainerMargins"
+            case .showNavigationController: return "Show Navigation Controller"
             }
         }
 
@@ -51,6 +57,8 @@ class SampleListViewController: UIViewController {
             case .trackingTextView: return "ConsoleViewController"
             case .showDetail: return "DetailViewController"
             case .showModal: return "ModalViewController"
+            case .showMultiPanelModal: return nil
+            case .showPanelInSheetModal: return nil
             case .showPanelModal: return nil
             case .showTabBar: return "TabBarViewController"
             case .showPageView: return nil
@@ -60,6 +68,7 @@ class SampleListViewController: UIViewController {
             case .showIntrinsicView: return "IntrinsicViewController"
             case .showContentInset: return nil
             case .showContainerMargins: return nil
+            case .showNavigationController: return "RootNavigationController"
             }
         }
     }
@@ -80,6 +89,7 @@ class SampleListViewController: UIViewController {
         tableView.dataSource = self
         tableView.delegate = self
         tableView.register(UITableViewCell.self, forCellReuseIdentifier: "Cell")
+        automaticallyAdjustsScrollViewInsets = false
 
         let searchController = UISearchController(searchResultsController: nil)
         if #available(iOS 11.0, *) {
@@ -92,11 +102,14 @@ class SampleListViewController: UIViewController {
 
         let contentVC = DebugTableViewController()
         addMainPanel(with: contentVC)
+
+        var insets = UIEdgeInsets.zero
+        insets.bottom += 69.0
+        tableView.contentInset = insets
     }
 
     override func viewDidAppear(_ animated: Bool) {
         super.viewDidAppear(animated)
-
         if #available(iOS 11.0, *) {
             if let observation = navigationController?.navigationBar.observe(\.prefersLargeTitles, changeHandler: { (bar, _) in
                 self.tableView.reloadData()
@@ -116,15 +129,13 @@ class SampleListViewController: UIViewController {
 
         let oldMainPanelVC = mainPanelVC
 
-        // Initialize FloatingPanelController
         mainPanelVC = FloatingPanelController()
         mainPanelVC.delegate = self
+        mainPanelVC.contentInsetAdjustmentBehavior = .always
 
-        // Initialize FloatingPanelController and add the view
         mainPanelVC.surfaceView.cornerRadius = 6.0
         mainPanelVC.surfaceView.shadowHidden = false
 
-        // Set a content view controller
         mainPanelVC.set(contentViewController: contentVC)
 
         // Enable tap-to-hide and removal interaction
@@ -143,6 +154,8 @@ class SampleListViewController: UIViewController {
 
             let backdropTapGesture = UITapGestureRecognizer(target: self, action: #selector(handleBackdrop(tapGesture:)))
             mainPanelVC.backdropView.addGestureRecognizer(backdropTapGesture)
+        case .showNavigationController:
+            mainPanelVC.contentInsetAdjustmentBehavior = .never
         default:
             break
         }
@@ -160,6 +173,11 @@ class SampleListViewController: UIViewController {
             mainPanelVC.track(scrollView: contentVC.tableView)
         case let contentVC as NestedScrollViewController:
             mainPanelVC.track(scrollView: contentVC.scrollView)
+        case let navVC as UINavigationController:
+            if let rootVC = (navVC.topViewController as? SampleListViewController) {
+                rootVC.loadViewIfNeeded()
+                mainPanelVC.track(scrollView: rootVC.tableView)
+            }
         default:
             break
         }
@@ -331,6 +349,24 @@ extension SampleListViewController: UITableViewDelegate {
 
             self.present(fpc, animated: true, completion: nil)
 
+        case .showMultiPanelModal:
+            let fpc = MultiPanelController()
+            self.present(fpc, animated: true, completion: nil)
+
+        case .showPanelInSheetModal:
+            let fpc = FloatingPanelController()
+            let contentVC = UIViewController()
+            fpc.set(contentViewController: contentVC)
+            fpc.delegate = self
+
+            fpc.surfaceView.cornerRadius = 38.5
+            fpc.surfaceView.shadowHidden = false
+            fpc.isRemovalInteractionEnabled = true
+
+            let mvc = UIViewController()
+            mvc.view.backgroundColor = UIColor(displayP3Red: 2/255, green: 184/255, blue: 117/255, alpha: 1.0)
+            fpc.addPanel(toParent: mvc)
+            self.present(mvc, animated: true, completion: nil)
         case .showContentInset:
             let contentViewController = UIViewController()
             contentViewController.view.backgroundColor = .green
@@ -368,6 +404,14 @@ extension SampleListViewController: UITableViewDelegate {
 }
 
 extension SampleListViewController: FloatingPanelControllerDelegate {
+    func floatingPanel(_ vc: FloatingPanelController, contentOffsetForPinning trackedScrollView: UIScrollView) -> CGPoint {
+        if currentMenu == .showNavigationController, #available(iOSApplicationExtension 11.0, *) {
+            // 148.0 is the SafeArea's top value for a navigation bar with a large title.
+            return CGPoint(x: 0.0, y: 0.0 - trackedScrollView.contentInset.top - 148.0)
+        }
+        return CGPoint(x: 0.0, y: 0.0 - trackedScrollView.contentInset.top)
+    }
+
     func floatingPanel(_ vc: FloatingPanelController, layoutFor newCollection: UITraitCollection) -> FloatingPanelLayout? {
         if vc == settingsPanelVC {
             return IntrinsicPanelLayout()
@@ -636,7 +680,8 @@ class InspectableViewController: UIViewController {
 }
 
 class DebugTableViewController: InspectableViewController {
-    weak var tableView: UITableView!
+    lazy var tableView = UITableView(frame: .zero, style: .plain)
+    lazy var buttonStackView = UIStackView()
     var items: [String] = []
     var itemHeight: CGFloat = 66.0
 
@@ -650,8 +695,6 @@ class DebugTableViewController: InspectableViewController {
     override func viewDidLoad() {
         super.viewDidLoad()
 
-        let tableView = UITableView(frame: .zero,
-                                    style: .plain)
         view.addSubview(tableView)
         tableView.translatesAutoresizingMaskIntoConstraints = false
         NSLayoutConstraint.activate([
@@ -662,18 +705,17 @@ class DebugTableViewController: InspectableViewController {
             ])
         tableView.dataSource = self
         tableView.delegate = self
-        self.tableView = tableView
+        tableView.register(UITableViewCell.self, forCellReuseIdentifier: "Cell")
 
-        let stackView = UIStackView()
-        view.addSubview(stackView)
-        stackView.axis = .vertical
-        stackView.distribution = .fillEqually
-        stackView.alignment = .trailing
-        stackView.spacing = 10.0
-        stackView.translatesAutoresizingMaskIntoConstraints = false
+        view.addSubview(buttonStackView)
+        buttonStackView.axis = .vertical
+        buttonStackView.distribution = .fillEqually
+        buttonStackView.alignment = .trailing
+        buttonStackView.spacing = 10.0
+        buttonStackView.translatesAutoresizingMaskIntoConstraints = false
         NSLayoutConstraint.activate([
-            stackView.topAnchor.constraint(equalTo: view.topAnchor, constant: 22.0),
-            stackView.rightAnchor.constraint(equalTo: view.rightAnchor, constant: -22.0),
+            buttonStackView.topAnchor.constraint(equalTo: view.topAnchor, constant: 22.0),
+            buttonStackView.rightAnchor.constraint(equalTo: view.rightAnchor, constant: -22.0),
             ])
 
         for menu in Menu.allCases {
@@ -689,13 +731,12 @@ class DebugTableViewController: InspectableViewController {
                 button.addTarget(self, action: #selector(reorderItems), for: .touchUpInside)
                 reorderButton = button
             }
-            stackView.addArrangedSubview(button)
+            buttonStackView.addArrangedSubview(button)
         }
 
         for i in 0...100 {
             items.append("Items \(i)")
         }
-        tableView.register(UITableViewCell.self, forCellReuseIdentifier: "Cell")
     }
 
     @objc func animateScroll() {
@@ -841,8 +882,7 @@ class ModalViewController: UIViewController, FloatingPanelControllerDelegate {
 
     var isNewlayout: Bool = false
 
-    override func viewWillAppear(_ animated: Bool) {
-        super.viewWillAppear(animated)
+    override func viewDidLoad() {
         // Initialize FloatingPanelController
         fpc = FloatingPanelController()
         fpc.delegate = self
@@ -862,8 +902,8 @@ class ModalViewController: UIViewController, FloatingPanelControllerDelegate {
         fpc.addPanel(toParent: self, belowView: safeAreaView)
     }
 
-    override func viewWillDisappear(_ animated: Bool) {
-        super.viewWillDisappear(animated)
+    override func viewDidDisappear(_ animated: Bool) {
+        super.viewDidDisappear(animated)
         //  Remove FloatingPanel from a view
         fpc.removePanelFromParent(animated: false)
     }
@@ -924,20 +964,15 @@ class TabBarContentViewController: UIViewController {
             }
         }
     }
-    var fpc: FloatingPanelController!
+    lazy var fpc = FloatingPanelController()
     var consoleVC: DebugTextViewController!
 
     var threeLayout: ThreeTabBarPanelLayout!
     var tab3Mode: Tab3Mode = .changeAutoLayout
     var switcherLabel: UILabel!
 
-    override func viewWillAppear(_ animated: Bool) {
-        super.viewWillAppear(animated)
-        // Initialize FloatingPanelController
-        fpc = FloatingPanelController()
+    override func viewDidLoad() {
         fpc.delegate = self
-
-        // Initialize FloatingPanelController and add the view
         fpc.surfaceView.cornerRadius = 6.0
         fpc.surfaceView.shadowHidden = false
 
@@ -987,12 +1022,6 @@ class TabBarContentViewController: UIViewController {
         fpc.updateLayout()
     }
 
-    override func viewWillDisappear(_ animated: Bool) {
-        super.viewWillDisappear(animated)
-        //  Remove FloatingPanel from a view
-        fpc.removePanelFromParent(animated: false)
-    }
-
     // MARK: - Action
 
     @IBAction func close(sender: UIButton) {
@@ -1270,3 +1299,83 @@ class SettingsViewController: InspectableViewController {
         navigationController?.navigationBar.isTranslucent = sender.isOn
     }
 }
+
+// MARK -: Multi Panel
+
+import WebKit
+final class MultiPanelController: FloatingPanelController, FloatingPanelControllerDelegate {
+
+    private final class FirstPanelContentViewController: UIViewController {
+
+        lazy var webView: WKWebView = WKWebView()
+
+        override func viewDidLoad() {
+            super.viewDidLoad()
+            view.addSubview(webView)
+            webView.frame = view.bounds
+            webView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
+            webView.load(URLRequest(url: URL(string: "https://www.apple.com")!))
+
+            let vc = MultiSecondPanelController()
+            vc.setUpContent()
+            vc.addPanel(toParent: self)
+        }
+    }
+
+    private final class MultiSecondPanelController: FloatingPanelController {
+
+        private final class SecondPanelContentViewController: DebugTableViewController {}
+
+        func setUpContent() {
+            contentInsetAdjustmentBehavior = .never
+            let vc = SecondPanelContentViewController()
+            vc.loadViewIfNeeded()
+            vc.title = "Second Panel"
+            vc.buttonStackView.isHidden = true
+            let navigationController = UINavigationController(rootViewController: vc)
+            navigationController.navigationBar.barTintColor = .white
+            navigationController.navigationBar.titleTextAttributes = [
+                .foregroundColor: UIColor.black
+            ]
+            set(contentViewController: navigationController)
+            self.track(scrollView: vc.tableView)
+            surfaceView.containerMargins = .init(top: 24.0, left: 0.0, bottom: layoutInsets.bottom, right: 0.0)
+        }
+    }
+
+    override func viewDidLoad() {
+        super.viewDidLoad()
+        delegate = self
+        isRemovalInteractionEnabled = true
+
+        let vc = FirstPanelContentViewController()
+        set(contentViewController: vc)
+        track(scrollView: vc.webView.scrollView)
+    }
+
+    private final class FirstViewLayout: FloatingPanelLayout {
+        let initialPosition: FloatingPanelPosition = .full
+        let supportedPositions: Set<FloatingPanelPosition> = [.full, .half]
+        func insetFor(position: FloatingPanelPosition) -> CGFloat? {
+            switch position {
+            case .full: return 40.0
+            case .half: return 200.0
+            default: return nil
+            }
+        }
+    }
+
+    private final class FirstViewBehavior: FloatingPanelBehavior {
+        func shouldProjectMomentum(_ fpc: FloatingPanelController, for proposedTargetPosition: FloatingPanelPosition) -> Bool {
+            return true
+        }
+    }
+
+    func floatingPanel(_ vc: FloatingPanelController, behaviorFor newCollection: UITraitCollection) -> FloatingPanelBehavior? {
+        return FirstViewBehavior()
+    }
+
+    func floatingPanel(_ vc: FloatingPanelController, layoutFor newCollection: UITraitCollection) -> FloatingPanelLayout? {
+        return FirstViewLayout()
+    }
+}

FloatingPanel.podspec

@@ -1,7 +1,7 @@
 Pod::Spec.new do |s|
 
   s.name                = "FloatingPanel"
-  s.version             = "1.7.2"
+  s.version             = "1.7.6"
   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/Sources/FloatingPanelController.swift

@@ -37,6 +37,15 @@ public protocol FloatingPanelControllerDelegate: class {
     ///
     /// By default, any tap and long gesture recognizers are allowed to recognize gestures simultaneously.
     func floatingPanel(_ vc: FloatingPanelController, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool
+
+    /// Asks the delegate for a content offset of the tracked scroll view to be pinned when a floating panel moves
+    ///
+    /// If you do not implement this method, the controller uses a value of the content offset plus the content insets
+    /// of the tracked scroll view. Your implementation of this method can return a value for a navigation bar with a large
+    /// title, for example.
+    ///
+    /// This method will not be called if the controller doesn't track any scroll view.
+    func floatingPanel(_ vc: FloatingPanelController, contentOffsetForPinning trackedScrollView: UIScrollView) -> CGPoint
 }
 
 public extension FloatingPanelControllerDelegate {
@@ -62,6 +71,9 @@ public extension FloatingPanelControllerDelegate {
     func floatingPanel(_ vc: FloatingPanelController, shouldRecognizeSimultaneouslyWith gestureRecognizer: UIGestureRecognizer) -> Bool {
         return false
     }
+    func floatingPanel(_ vc: FloatingPanelController, contentOffsetForPinning trackedScrollView: UIScrollView) -> CGPoint {
+        return CGPoint(x: 0.0, y: 0.0 - trackedScrollView.contentInset.top)
+    }
 }
 
 
@@ -359,7 +371,6 @@ open class FloatingPanelController: UIViewController {
         switch contentInsetAdjustmentBehavior {
         case .always:
             scrollView?.contentInset = adjustedContentInsets
-            scrollView?.scrollIndicatorInsets = adjustedContentInsets
         default:
             break
         }
@@ -381,13 +392,18 @@ open class FloatingPanelController: UIViewController {
     private func activateLayout() {
         floatingPanel.layoutAdapter.prepareLayout(in: self)
 
-        // preserve the current content offset
-        let contentOffset = scrollView?.contentOffset
+        // preserve the current content offset if contentInsetAdjustmentBehavior is `.always`
+        var contentOffset: CGPoint?
+        if contentInsetAdjustmentBehavior == .always {
+            contentOffset = scrollView?.contentOffset
+        }
 
         floatingPanel.layoutAdapter.updateHeight()
         floatingPanel.layoutAdapter.activateLayout(of: floatingPanel.state)
 
-        scrollView?.contentOffset = contentOffset ?? .zero
+        if let contentOffset = contentOffset {
+            scrollView?.contentOffset = contentOffset
+        }
     }
 
     // MARK: - Container view controller interface
@@ -405,9 +421,11 @@ open class FloatingPanelController: UIViewController {
             // inset's update expectedly.
             // 2. The safe area top inset can be variable on the large title navigation bar(iOS11+).
             // That's why it needs the observation to keep `adjustedContentInsets` correct.
-            safeAreaInsetsObservation = self.observe(\.view.safeAreaInsets, options: [.initial, .new, .old]) { [weak self] (vc, change) in
-                guard change.oldValue != change.newValue else { return }
-                self?.update(safeAreaInsets: vc.layoutInsets)
+            safeAreaInsetsObservation = self.view.observe(\.safeAreaInsets, options: [.initial, .new, .old]) { [weak self] (_, change) in
+                // Use `self.view.safeAreaInsets` becauese `change.newValue` can be nil in particular case when
+                // is reported in https://github.com/SCENEE/FloatingPanel/issues/330
+                guard let `self` = self, change.oldValue != self.view.safeAreaInsets else { return }
+                self.update(safeAreaInsets: self.view.safeAreaInsets)
             }
         } else {
             // KVOs for topLayoutGuide & bottomLayoutGuide are not effective.
@@ -652,7 +670,8 @@ public extension UIViewController {
         }
         // Call dismiss(animated:completion:) to FloatingPanelController directly
         if let fpc = self as? FloatingPanelController {
-            if fpc.presentingViewController != nil {
+            // When a panel is presented modally and it's not a child view controller of the presented view controller.
+            if fpc.presentingViewController != nil, fpc.parent == nil {
                 self.fp_original_dismiss(animated: flag, completion: completion)
             } else {
                 fpc.removePanelFromParent(animated: flag, completion: completion)

Framework/Sources/FloatingPanelCore.swift

@@ -97,7 +97,7 @@ class FloatingPanelCore: NSObject, UIGestureRecognizerDelegate {
     }
 
     private func move(from: FloatingPanelPosition, to: FloatingPanelPosition, animated: Bool, completion: (() -> Void)? = nil) {
-        assert(layoutAdapter.isValid(to), "Can't move to '\(to)' position because it's not valid in the layout")
+        assert(layoutAdapter.validPositions.contains(to), "Can't move to '\(to)' position because it's not valid in the layout")
         guard let vc = viewcontroller else {
             completion?()
             return
@@ -191,6 +191,9 @@ class FloatingPanelCore: NSObject, UIGestureRecognizerDelegate {
         }
 
         switch otherGestureRecognizer {
+        case is FloatingPanelPanGestureRecognizer:
+            // All visiable panels' pan gesture should be recognized simultaneously.
+            return true
         case is UIPanGestureRecognizer,
              is UISwipeGestureRecognizer,
              is UIRotationGestureRecognizer,
@@ -210,8 +213,19 @@ class FloatingPanelCore: NSObject, UIGestureRecognizerDelegate {
     }
 
     public func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldBeRequiredToFailBy otherGestureRecognizer: UIGestureRecognizer) -> Bool {
-        guard gestureRecognizer == panGestureRecognizer else { return false }
         /* log.debug("shouldBeRequiredToFailBy", otherGestureRecognizer) */
+        if otherGestureRecognizer is FloatingPanelPanGestureRecognizer {
+            // If this panel is the farthest descendant of visiable panels,
+            // its ancestors' pan gesture must wait for its pan gesture to fail
+            if let view = otherGestureRecognizer.view, surfaceView.isDescendant(of: view) {
+                return true
+            }
+        }
+        if #available(iOS 11.0, *),
+            otherGestureRecognizer.name == "_UISheetInteractionBackgroundDismissRecognizer" {
+            // The dismiss gesture of a sheet modal should not begin until the pan gesture fails.
+            return true
+        }
         return false
     }
 
@@ -237,8 +251,7 @@ class FloatingPanelCore: NSObject, UIGestureRecognizerDelegate {
                     if grabberAreaFrame.contains(gestureRecognizer.location(in: gestureRecognizer.view)) {
                         return false
                     }
-                    let offset = scrollView.contentOffset.y - scrollView.contentOffsetZero.y
-                    return allowScrollPanGesture(at: CGPoint(x: 0.0, y: offset))
+                    return allowScrollPanGesture(for: scrollView)
                 default:
                     return false
                 }
@@ -251,11 +264,23 @@ class FloatingPanelCore: NSObject, UIGestureRecognizerDelegate {
         }
 
         switch otherGestureRecognizer {
+        case is FloatingPanelPanGestureRecognizer:
+            // If this panel is the farthest descendant of visiable panels,
+            // its pan gesture does not require its ancestors' pan gesture to fail
+            if let view = otherGestureRecognizer.view, surfaceView.isDescendant(of: view) {
+                return false
+            }
+            return true
         case is UIPanGestureRecognizer,
              is UISwipeGestureRecognizer,
              is UIRotationGestureRecognizer,
              is UIScreenEdgePanGestureRecognizer,
              is UIPinchGestureRecognizer:
+            if #available(iOS 11.0, *),
+                otherGestureRecognizer.name == "_UISheetInteractionBackgroundDismissRecognizer" {
+                // Should begin the pan gesture without waiting the dismiss gesture of a sheet modal.
+                return false
+            }
             // Do not begin the pan gesture until these gestures fail
             return true
         default:
@@ -293,14 +318,13 @@ class FloatingPanelCore: NSObject, UIGestureRecognizerDelegate {
             let surfaceMinY = surfaceView.presentationFrame.minY
             let adapterTopY = layoutAdapter.topY
             let belowTop = surfaceMinY > (adapterTopY + (1.0 / surfaceView.traitCollection.displayScale))
-            let offset = scrollView.contentOffset.y - scrollView.contentOffsetZero.y
-
             log.debug("scroll gesture(\(state):\(panGesture.state)) --",
                 "belowTop = \(belowTop),",
                 "interactionInProgress = \(interactionInProgress),",
-                "scroll offset = \(offset),",
+                "scroll offset = \(scrollView.contentOffset.y),",
                 "location = \(location.y), velocity = \(velocity.y)")
 
+            let offset = scrollView.contentOffset.y - contentOrigin(of: scrollView).y
 
             if belowTop {
                 // Scroll offset pinning
@@ -343,11 +367,11 @@ class FloatingPanelCore: NSObject, UIGestureRecognizerDelegate {
                 } else {
                     if state == layoutAdapter.topMostState {
                         // Hide a scroll indicator just before starting an interaction by swiping a panel down.
-                        if velocity.y > 0, !allowScrollPanGesture(at: CGPoint(x: 0.0, y: offset)) {
+                        if velocity.y > 0, !allowScrollPanGesture(for: scrollView) {
                             lockScrollView()
                         }
                         // Show a scroll indicator when an animation is interrupted at the top and content is scrolled up
-                        if velocity.y < 0, allowScrollPanGesture(at: CGPoint(x: 0.0, y: offset)) {
+                        if velocity.y < 0, allowScrollPanGesture(for: scrollView) {
                             unlockScrollView()
                         }
 
@@ -450,14 +474,15 @@ class FloatingPanelCore: NSObject, UIGestureRecognizerDelegate {
             return true
         }
 
+        let scrollViewFrame = scrollView.convert(scrollView.bounds, to: surfaceView)
         guard
-            scrollView.frame.contains(initialLocation), // When initialLocation not in scrollView, don't scroll.
+            scrollViewFrame.contains(initialLocation), // When initialLocation not in scrollView, don't scroll.
             !grabberAreaFrame.contains(point)           // When point within grabber area, don't scroll.
         else {
             return false
         }
 
-        let offset = scrollView.contentOffset.y - scrollView.contentOffsetZero.y
+        let offset = scrollView.contentOffset.y - contentOrigin(of: scrollView).y
         // 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 {
@@ -592,16 +617,24 @@ class FloatingPanelCore: NSObject, UIGestureRecognizerDelegate {
 
         endInteraction(for: targetPosition)
 
-        if isRemovalInteractionEnabled, isBottomState {
-            let velocityVector = (distance != 0) ? CGVector(dx: 0, dy: min(velocity.y/distance, behavior.removalVelocity)) : .zero
+        if isRemovalInteractionEnabled {
+            let velocityVector: CGVector
+            if distance == 0 {
+                velocityVector = .zero
+            } else {
+                let dy = min(velocity.y / abs(distance), behavior.removalVelocity)
+                velocityVector = CGVector(dx: 0, dy: dy)
+            }
             // `velocityVector` will be replaced by just a velocity(not vector) when FloatingPanelRemovalInteraction will be added.
             if shouldStartRemovalAnimation(with: velocityVector), let vc = viewcontroller {
-                vc.delegate?.floatingPanelDidEndDraggingToRemove(vc, withVelocity: velocity)
-                let animationVector = CGVector(dx: abs(velocityVector.dx), dy: abs(velocityVector.dy))
-                startRemovalAnimation(vc, with: animationVector) { [weak self] in
-                    self?.finishRemovalAnimation()
+                if behavior.shouldProjectMomentum(vc, for: targetPosition) || isBottomState {
+                    vc.delegate?.floatingPanelDidEndDraggingToRemove(vc, withVelocity: velocity)
+                    let animationVector = CGVector(dx: abs(velocityVector.dx), dy: abs(velocityVector.dy))
+                    startRemovalAnimation(vc, with: animationVector) { [weak self] in
+                        self?.finishRemovalAnimation()
+                    }
+                    return
                 }
-                return
             }
         }
 
@@ -683,12 +716,12 @@ class FloatingPanelCore: NSObject, UIGestureRecognizerDelegate {
 
         initialFrame = surfaceView.frame
         if state == layoutAdapter.topMostState, let scrollView = scrollView {
-            if grabberAreaFrame.contains(location) || scrollView.isTracking == false {
+            if grabberAreaFrame.contains(location) {
                 initialScrollOffset = scrollView.contentOffset
             } else {
-                initialScrollOffset = scrollView.contentOffsetZero
+                initialScrollOffset = contentOrigin(of: scrollView)
                 // Fit the surface bounds to a scroll offset content by startInteraction(at:offset:)
-                let scrollOffsetY = (scrollView.contentOffset.y - scrollView.contentOffsetZero.y)
+                let scrollOffsetY = (scrollView.contentOffset.y - contentOrigin(of: scrollView).y)
                 if scrollOffsetY < 0 {
                     offset = CGPoint(x: -scrollView.contentOffset.x, y: -scrollOffsetY)
                 }
@@ -740,7 +773,7 @@ class FloatingPanelCore: NSObject, UIGestureRecognizerDelegate {
 
         vc.delegate?.floatingPanelWillBeginDecelerating(vc)
 
-        let velocityVector = (distance != 0) ? CGVector(dx: 0, dy: abs(velocity.y)/distance) : .zero
+        let velocityVector = (distance != 0) ? CGVector(dx: 0, dy: velocity.y / distance) : .zero
         let animator = behavior.interactionAnimator(vc, to: targetPosition, with: velocityVector)
         animator.addAnimations { [weak self] in
             guard let `self` = self, let vc = self.viewcontroller else { return }
@@ -794,7 +827,7 @@ class FloatingPanelCore: NSObject, UIGestureRecognizerDelegate {
     private func distance(to targetPosition: FloatingPanelPosition) -> CGFloat {
         let currentY = surfaceView.frame.minY
         let targetY = layoutAdapter.positionY(for: targetPosition)
-        return CGFloat(abs(currentY - targetY))
+        return CGFloat(targetY - currentY)
     }
 
     // Distance travelled after decelerating to zero velocity at a constant rate.
@@ -889,7 +922,15 @@ class FloatingPanelCore: NSObject, UIGestureRecognizerDelegate {
         scrollView?.setContentOffset(contentOffset, animated: false)
     }
 
-    private func allowScrollPanGesture(at contentOffset: CGPoint) -> Bool {
+    private func contentOrigin(of scrollView: UIScrollView) -> CGPoint {
+        if let vc = viewcontroller, let origin = vc.delegate?.floatingPanel(vc, contentOffsetForPinning: scrollView) {
+            return origin
+        }
+        return CGPoint(x: 0.0, y: 0.0 - scrollView.contentInset.top)
+    }
+
+    private func allowScrollPanGesture(for scrollView: UIScrollView) -> Bool {
+        let contentOffset = scrollView.contentOffset - contentOrigin(of: scrollView)
         if state == layoutAdapter.topMostState {
             return contentOffset.y <= -30.0 || contentOffset.y > 0
         }

Framework/Sources/FloatingPanelLayout.swift

@@ -211,6 +211,10 @@ class FloatingPanelLayoutAdapter {
         return layout.supportedPositions
     }
 
+    var validPositions: Set<FloatingPanelPosition> {
+        return supportedPositions.union([.hidden])
+    }
+
     var topMostState: FloatingPanelPosition {
         return supportedPositions.sorted(by: { $0.rawValue < $1.rawValue }).first ?? .hidden
     }
@@ -398,8 +402,8 @@ class FloatingPanelLayoutAdapter {
         // unsatisfiable constraints
 
         if self.interactiveTopConstraint == nil {
-            // Actiavate `interactiveTopConstraint` for `fitToBounds` mode.
-            // It goes throught this path when the pan gesture state jumps
+            // Activate `interactiveTopConstraint` for `fitToBounds` mode.
+            // It goes through this path when the pan gesture state jumps
             // from .begin to .end.
             startInteraction(at: state)
         }
@@ -453,7 +457,7 @@ class FloatingPanelLayoutAdapter {
             case .fromSuperview:
                 ret = topY
             }
-            return max(ret, 0.0) // The top boundary is equal to the related topAnchor.
+            return ret
         }()
         let bottomMostConst: CGFloat = {
             var ret: CGFloat = 0.0
@@ -464,7 +468,7 @@ class FloatingPanelLayoutAdapter {
             case .fromSuperview:
                 ret = _bottomY
             }
-            return min(ret, surfaceView.superview!.bounds.height)
+            return ret
         }()
         let minConst = allowsTopBuffer ? topMostConst - layout.topInteractionBuffer : topMostConst
         let maxConst = bottomMostConst + layout.bottomInteractionBuffer
@@ -516,7 +520,7 @@ class FloatingPanelLayoutAdapter {
 
         setBackdropAlpha(of: state)
 
-        if isValid(state) == false {
+        if validPositions.contains(state) == false {
             state = layout.initialPosition
         }
 
@@ -538,10 +542,6 @@ class FloatingPanelLayoutAdapter {
         activateInteractiveLayout(of: state)
     }
 
-    func isValid(_ state: FloatingPanelPosition) -> Bool {
-        return supportedPositions.union([.hidden]).contains(state)
-    }
-
     private func layoutSurfaceIfNeeded() {
         #if !TEST
         guard surfaceView.window != nil else { return }
@@ -560,8 +560,8 @@ class FloatingPanelLayoutAdapter {
     private func checkLayoutConsistance() {
         // Verify layout configurations
         assert(supportedPositions.count > 0)
-        assert(supportedPositions.contains(layout.initialPosition),
-               "Does not include an initial position (\(layout.initialPosition)) in supportedPositions (\(supportedPositions))")
+        assert(validPositions.contains(layout.initialPosition),
+               "Does not include an initial position (\(layout.initialPosition)) in (\(validPositions))")
 
         if layout is FloatingPanelIntrinsicLayout {
             assert(layout.insetFor(position: .full) == nil, "Return `nil` for full position on FloatingPanelIntrinsicLayout")

Framework/Sources/FloatingPanelSurfaceView.swift

@@ -228,6 +228,7 @@ public class FloatingPanelSurfaceView: UIView {
         let rightConstraint = rightAnchor.constraint(equalTo: contentView.rightAnchor, constant: containerMargins.right + contentInsets.right)
         let heightPadding = containerMargins.top + containerMargins.bottom + contentInsets.top + contentInsets.bottom
         let heightConstraint = contentView.heightAnchor.constraint(equalTo: heightAnchor, constant: -heightPadding)
+        heightConstraint.priority = UILayoutPriority(999)
         NSLayoutConstraint.activate([
             topConstraint,
             leftConstraint,

Framework/Sources/FloatingPanelTransitioning.swift

@@ -47,8 +47,15 @@ class FloatingPanelPresentationController: UIPresentationController {
 
     override func containerViewWillLayoutSubviews() {
         guard
-            let fpc = presentedViewController as? FloatingPanelController
-            else { fatalError() }
+            let fpc = presentedViewController as? FloatingPanelController,
+            /**
+             This condition fixes https://github.com/SCENEE/FloatingPanel/issues/369.
+             The issue is that this method is called in presenting a
+             UIImagePickerViewController and then a FloatingPanelController
+             view is added unnecessarily.
+             */
+            fpc.presentedViewController == nil
+            else { return }
 
         /*
          * Layout the views managed by `FloatingPanelController` here for the

Framework/Sources/Info.plist

@@ -15,7 +15,7 @@
 	<key>CFBundlePackageType</key>
 	<string>FMWK</string>
 	<key>CFBundleShortVersionString</key>
-	<string>1.7.2</string>
+	<string>1.7.6</string>
 	<key>CFBundleVersion</key>
 	<string>$(CURRENT_PROJECT_VERSION)</string>
 </dict>

Framework/Sources/UIExtensions.swift

@@ -114,9 +114,6 @@ extension UIGestureRecognizerState: CustomDebugStringConvertible {
 #endif
 
 extension UIScrollView {
-    var contentOffsetZero: CGPoint {
-        return CGPoint(x: 0.0, y: 0.0 - contentInset.top)
-    }
     var isLocked: Bool {
         return !showsVerticalScrollIndicator && !bounces &&  isDirectionalLockEnabled
     }
@@ -133,8 +130,10 @@ extension UISpringTimingParameters {
 
 extension CGPoint {
     static var nan: CGPoint {
-        return CGPoint(x: CGFloat.nan,
-                       y: CGFloat.nan)
+        return CGPoint(x: CGFloat.nan, y: CGFloat.nan)
+    }
+    static func - (left: CGPoint, right: CGPoint) -> CGPoint {
+        return CGPoint(x: left.x - right.x, y: left.y - right.y)
     }
 }
 

Framework/Tests/FloatingPanelLayoutTests.swift

@@ -195,6 +195,43 @@ class FloatingPanelLayoutTests: XCTestCase {
         fpc.floatingPanel.layoutAdapter.endInteraction(at: fpc.position)
     }
 
+    func test_updateInteractiveTopConstraintWithMinusInsets() {
+        class FloatingPanelLayoutMinusInsets: FloatingPanelTestLayout {
+            let initialPosition: FloatingPanelPosition = .full
+            let supportedPositions: Set<FloatingPanelPosition> = [.tip, .full]
+            func insetFor(position: FloatingPanelPosition) -> CGFloat? {
+                switch position {
+                case .full, .tip: return -200
+                default: return nil
+                }
+            }
+        }
+        let delegate = FloatingPanelTestDelegate()
+        delegate.layout = FloatingPanelLayoutMinusInsets()
+        fpc.delegate = delegate
+        fpc.showForTest()
+        fpc.floatingPanel.layoutAdapter.startInteraction(at: fpc.position)
+
+        let fullPos = fpc.originYOfSurface(for: .full)
+        let tipPos = fpc.originYOfSurface(for: .tip)
+        let current = fpc.surfaceView.frame.minY
+
+        var next: CGFloat
+        fpc.floatingPanel.layoutAdapter.updateInteractiveTopConstraint(diff: -100.0, allowsTopBuffer: false, with: fpc.behavior)
+        next = fpc.surfaceView.frame.minY
+        XCTAssertEqual(next, current)
+
+        fpc.floatingPanel.layoutAdapter.updateInteractiveTopConstraint(diff: -100.0, allowsTopBuffer: true, with: fpc.behavior)
+        next = fpc.surfaceView.frame.minY
+        XCTAssertEqual(next, fullPos - fpc.layout.topInteractionBuffer)
+
+        fpc.floatingPanel.layoutAdapter.updateInteractiveTopConstraint(diff: tipPos - fullPos + 100.0, allowsTopBuffer: true, with: fpc.behavior)
+        next = fpc.surfaceView.frame.minY
+        XCTAssertEqual(next, tipPos + fpc.layout.bottomInteractionBuffer)
+
+        fpc.floatingPanel.layoutAdapter.endInteraction(at: fpc.position)
+    }
+
     func test_positionReference() {
         fpc = CustomSafeAreaFloatingPanelController()
         fpc.loadViewIfNeeded()

README.md

@@ -36,7 +36,7 @@ The new interface displays the related contents and utilities in parallel as a u
     - [Change the initial position and height](#change-the-initial-position-and-height)
     - [Support your landscape layout](#support-your-landscape-layout)
     - [Use Intrinsic height layout](#use-intrinsic-height-layout)
-    - [Specify position insets from the frame of `FloatingPanelContrller.view`, not the SafeArea](#specify-position-insets-from-the-frame-of-floatingpanelcontrllerview-not-the-safearea)
+    - [Specify position insets from the frame of `FloatingPanelController.view`, not the SafeArea](#specify-position-insets-from-the-frame-of-floatingpanelcontrollerview-not-the-safearea)
   - [Customize the behavior with `FloatingPanelBehavior` protocol](#customize-the-behavior-with-floatingpanelbehavior-protocol)
     - [Modify your floating panel's interaction](#modify-your-floating-panels-interaction)
     - [Activate the rubber-band effect on the top/bottom edges](#activate-the-rubber-band-effect-on-the-topbottom-edges)
@@ -138,13 +138,6 @@ class ViewController: UIViewController, FloatingPanelControllerDelegate {
         // Add and show the views managed by the `FloatingPanelController` object to self.view.
         fpc.addPanel(toParent: self)
     }
-
-    override func viewWillDisappear(_ animated: Bool) {
-        super.viewWillDisappear(animated)
-
-        // Remove the views managed by the `FloatingPanelController` object from self.view.
-        fpc.removePanelFromParent()
-    }
 }
 ```
 
@@ -338,7 +331,7 @@ class RemovablePanelLayout: FloatingPanelIntrinsicLayout {
 }
 ```
 
-#### Specify position insets from the frame of `FloatingPanelContrller.view`, not the SafeArea
+#### Specify position insets from the frame of `FloatingPanelController.view`, not the SafeArea
 
 There are 2 ways. One is returning `.fromSuperview` for `FloatingPanelLayout.positionReference` in your layout.
 
@@ -447,7 +440,7 @@ The feature can be used for these 2 kind panels
 You can disable the pan gesture recognizer directly
 
 ```swift
-fpc.panGestureRecognizer.isEnable = false
+fpc.panGestureRecognizer.isEnabled = false
 ```
 
 Or use this `FloatingPanelControllerDelegate` method.