Zoom transition

Metatext.xcodeproj/project.pbxproj

@@ -22,6 +22,10 @@
 		D08B8D3D253F929E00B1EBEF /* ImageViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D08B8D3C253F929E00B1EBEF /* ImageViewController.swift */; };
 		D08B8D42253F92B600B1EBEF /* ImagePageViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D08B8D41253F92B600B1EBEF /* ImagePageViewController.swift */; };
 		D08B8D4A253FC36500B1EBEF /* ImageNavigationController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D08B8D49253FC36500B1EBEF /* ImageNavigationController.swift */; };
+		D08B8D602540DE3B00B1EBEF /* ZoomAnimator.swift in Sources */ = {isa = PBXBuildFile; fileRef = D08B8D5D2540DE3A00B1EBEF /* ZoomAnimator.swift */; };
+		D08B8D612540DE3B00B1EBEF /* ZoomDismissalInteractionController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D08B8D5E2540DE3A00B1EBEF /* ZoomDismissalInteractionController.swift */; };
+		D08B8D622540DE3B00B1EBEF /* ZoomTransitionController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D08B8D5F2540DE3A00B1EBEF /* ZoomTransitionController.swift */; };
+		D08B8D672540DEB200B1EBEF /* ZoomAnimatableView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D08B8D662540DEB200B1EBEF /* ZoomAnimatableView.swift */; };
 		D0A1F4F7252E7D4B004435BF /* TableViewDataSource.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0A1F4F6252E7D4B004435BF /* TableViewDataSource.swift */; };
 		D0A3C2F725390A9700739F88 /* AppPreferences+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0A3C2F625390A9700739F88 /* AppPreferences+Extensions.swift */; };
 		D0B32F50250B373600311912 /* RegistrationView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0B32F4F250B373600311912 /* RegistrationView.swift */; };
@@ -122,6 +126,10 @@
 		D08B8D3C253F929E00B1EBEF /* ImageViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ImageViewController.swift; sourceTree = "<group>"; };
 		D08B8D41253F92B600B1EBEF /* ImagePageViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ImagePageViewController.swift; sourceTree = "<group>"; };
 		D08B8D49253FC36500B1EBEF /* ImageNavigationController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ImageNavigationController.swift; sourceTree = "<group>"; };
+		D08B8D5D2540DE3A00B1EBEF /* ZoomAnimator.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ZoomAnimator.swift; sourceTree = "<group>"; };
+		D08B8D5E2540DE3A00B1EBEF /* ZoomDismissalInteractionController.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ZoomDismissalInteractionController.swift; sourceTree = "<group>"; };
+		D08B8D5F2540DE3A00B1EBEF /* ZoomTransitionController.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ZoomTransitionController.swift; sourceTree = "<group>"; };
+		D08B8D662540DEB200B1EBEF /* ZoomAnimatableView.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ZoomAnimatableView.swift; sourceTree = "<group>"; };
 		D0A1F4F6252E7D4B004435BF /* TableViewDataSource.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TableViewDataSource.swift; sourceTree = "<group>"; };
 		D0A3C2F625390A9700739F88 /* AppPreferences+Extensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "AppPreferences+Extensions.swift"; sourceTree = "<group>"; };
 		D0AD03552505814D0085A466 /* Base16 */ = {isa = PBXFileReference; lastKnownFileType = folder; path = Base16; sourceTree = "<group>"; };
@@ -234,6 +242,7 @@
 				D0C7D41D24F76169001EBDBB /* Supporting Files */,
 				D0C7D45324F76169001EBDBB /* System */,
 				D0666A2224C677B400F3F04B /* Tests */,
+				D08B8D5C2540DDFC00B1EBEF /* Transitions */,
 				D0C7D43024F76169001EBDBB /* View Controllers */,
 				D0E2C1CF24FD8BA400854680 /* ViewModels */,
 				D0C7D42024F76169001EBDBB /* Views */,
@@ -278,6 +287,17 @@
 			name = Frameworks;
 			sourceTree = "<group>";
 		};
+		D08B8D5C2540DDFC00B1EBEF /* Transitions */ = {
+			isa = PBXGroup;
+			children = (
+				D08B8D662540DEB200B1EBEF /* ZoomAnimatableView.swift */,
+				D08B8D5D2540DE3A00B1EBEF /* ZoomAnimator.swift */,
+				D08B8D5E2540DE3A00B1EBEF /* ZoomDismissalInteractionController.swift */,
+				D08B8D5F2540DE3A00B1EBEF /* ZoomTransitionController.swift */,
+			);
+			path = Transitions;
+			sourceTree = "<group>";
+		};
 		D0A1F4F5252E7D2A004435BF /* Data Sources */ = {
 			isa = PBXGroup;
 			children = (
@@ -569,12 +589,14 @@
 				D0C7D49C24F7616A001EBDBB /* RootView.swift in Sources */,
 				D0F0B126251A90F400942152 /* AccountListCell.swift in Sources */,
 				D0B32F50250B373600311912 /* RegistrationView.swift in Sources */,
+				D08B8D612540DE3B00B1EBEF /* ZoomDismissalInteractionController.swift in Sources */,
 				D0E569E0252931B100FA1D72 /* LoadMoreContentConfiguration.swift in Sources */,
 				D0FE1C9825368A9D003EF1EB /* PlayerCache.swift in Sources */,
 				D0F0B136251AA12700942152 /* CollectionItem+Extensions.swift in Sources */,
 				D0625E5D250F0B5C00502611 /* StatusContentConfiguration.swift in Sources */,
 				D0BEB1F324F8EE8C001B0F04 /* StatusAttachmentView.swift in Sources */,
 				D0C7D49A24F7616A001EBDBB /* TableView.swift in Sources */,
+				D08B8D622540DE3B00B1EBEF /* ZoomTransitionController.swift in Sources */,
 				D0F0B12E251A97E400942152 /* TableViewController.swift in Sources */,
 				D0FE1C8F253686F9003EF1EB /* PlayerView.swift in Sources */,
 				D0F0B113251A86A000942152 /* AccountContentConfiguration.swift in Sources */,
@@ -586,6 +608,8 @@
 				D0C7D49D24F7616A001EBDBB /* PostingReadingPreferencesView.swift in Sources */,
 				D0B5FE9B251583DB00478838 /* ProfileCollection+Extensions.swift in Sources */,
 				D0C7D49E24F7616A001EBDBB /* SecondaryNavigationView.swift in Sources */,
+				D08B8D602540DE3B00B1EBEF /* ZoomAnimator.swift in Sources */,
+				D08B8D672540DEB200B1EBEF /* ZoomAnimatableView.swift in Sources */,
 				D0C7D4DA24F7616A001EBDBB /* View+Extensions.swift in Sources */,
 				D0C7D4D524F7616A001EBDBB /* String+Extensions.swift in Sources */,
 				D0C7D4A224F7616A001EBDBB /* NotificationTypesPreferencesView.swift in Sources */,

Transitions/ZoomAnimatableView.swift

@@ -0,0 +1,43 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import AVFoundation
+import UIKit
+
+protocol ZoomAnimatableView {
+    func transitionView() -> UIView
+    func frame(inView view: UIView) -> CGRect
+}
+
+extension UIImageView: ZoomAnimatableView {
+    func transitionView() -> UIView {
+        let transitionView = UIImageView(image: image)
+
+        transitionView.contentMode = .scaleAspectFill
+        transitionView.clipsToBounds = true
+
+        return transitionView
+    }
+
+    func frame(inView view: UIView) -> CGRect {
+        guard let image = image else { return .zero }
+
+        return AVMakeRect(aspectRatio: image.size, insideRect: view.frame)
+    }
+}
+
+extension PlayerView: ZoomAnimatableView {
+    func transitionView() -> UIView {
+        let transitionView = PlayerView()
+
+        transitionView.videoGravity = .resizeAspectFill
+        transitionView.player = player
+
+        return transitionView
+    }
+
+    func frame(inView view: UIView) -> CGRect {
+        guard let item = player?.currentItem else { return .zero }
+
+        return AVMakeRect(aspectRatio: item.presentationSize, insideRect: view.frame)
+    }
+}

Transitions/ZoomAnimator.swift

@@ -0,0 +1,128 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import UIKit
+
+protocol ZoomAnimatorDelegate: class {
+    func transitionWillStartWith(zoomAnimator: ZoomAnimator)
+    func transitionDidEndWith(zoomAnimator: ZoomAnimator)
+    func referenceView(for zoomAnimator: ZoomAnimator) -> UIView?
+    func referenceViewFrameInTransitioningView(for zoomAnimator: ZoomAnimator) -> CGRect?
+}
+
+class ZoomAnimator: NSObject {
+    weak var fromDelegate: ZoomAnimatorDelegate?
+    weak var toDelegate: ZoomAnimatorDelegate?
+
+    var transitionView: UIView?
+    var isPresenting = true
+}
+
+extension ZoomAnimator: UIViewControllerAnimatedTransitioning {
+    func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
+        isPresenting ? .defaultAnimationDuration : .shortAnimationDuration
+    }
+
+    func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
+        fromDelegate?.transitionWillStartWith(zoomAnimator: self)
+        toDelegate?.transitionWillStartWith(zoomAnimator: self)
+
+        if isPresenting {
+            animateZoomInTransition(using: transitionContext)
+        } else {
+            animateZoomOutTransition(using: transitionContext)
+        }
+    }
+}
+
+private extension ZoomAnimator {
+    private func animateZoomInTransition(using transitionContext: UIViewControllerContextTransitioning) {
+        guard
+            let toVC = transitionContext.viewController(forKey: .to),
+            let fromVC = transitionContext.viewController(forKey: .from),
+            let fromReferenceView = fromDelegate?.referenceView(for: self),
+            let toReferenceView = toDelegate?.referenceView(for: self),
+            let fromReferenceViewFrame = fromDelegate?.referenceViewFrameInTransitioningView(for: self)
+            else { return }
+
+        toVC.view.alpha = 0
+        toReferenceView.isHidden = true
+        transitionContext.containerView.addSubview(toVC.view)
+
+        if transitionView == nil, let transitionView = (fromReferenceView as? ZoomAnimatableView)?.transitionView() {
+            transitionView.frame = fromReferenceViewFrame
+            self.transitionView = transitionView
+            transitionContext.containerView.addSubview(transitionView)
+        }
+
+        fromReferenceView.isHidden = true
+
+        let finalTransitionSize = (fromReferenceView as? ZoomAnimatableView)?.frame(inView: toVC.view) ?? .zero
+
+        UIView.animate(
+            withDuration: transitionDuration(using: transitionContext),
+            delay: 0,
+            usingSpringWithDamping: 0.8,
+            initialSpringVelocity: 0,
+            options: [.transitionCrossDissolve]) {
+            self.transitionView?.frame = finalTransitionSize
+            toVC.view.alpha = 1.0
+            fromVC.tabBarController?.tabBar.alpha = 0
+        } completion: { _ in
+            self.transitionView?.removeFromSuperview()
+            toReferenceView.isHidden = false
+            fromReferenceView.isHidden = false
+
+            self.transitionView = nil
+
+            transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
+            self.toDelegate?.transitionDidEndWith(zoomAnimator: self)
+            self.fromDelegate?.transitionDidEndWith(zoomAnimator: self)
+        }
+    }
+
+    private func animateZoomOutTransition(using transitionContext: UIViewControllerContextTransitioning) {
+        let containerView = transitionContext.containerView
+
+        guard
+            let toVC = transitionContext.viewController(forKey: UITransitionContextViewControllerKey.to),
+            let fromVC = transitionContext.viewController(forKey: UITransitionContextViewControllerKey.from),
+            let fromReferenceView = fromDelegate?.referenceView(for: self),
+            let fromReferenceViewFrame = fromDelegate?.referenceViewFrameInTransitioningView(for: self)
+            else { return }
+
+        let toReferenceView = toDelegate?.referenceView(for: self)
+        let toReferenceViewFrame = toDelegate?.referenceViewFrameInTransitioningView(for: self)
+
+        toReferenceView?.isHidden = true
+
+        if transitionView == nil, let transitionView = (fromReferenceView as? ZoomAnimatableView)?.transitionView() {
+            transitionView.frame = fromReferenceViewFrame
+            self.transitionView = transitionView
+            containerView.addSubview(transitionView)
+        }
+
+        containerView.insertSubview(toVC.view, belowSubview: fromVC.view)
+        fromReferenceView.isHidden = true
+
+        UIView.animate(
+            withDuration: transitionDuration(using: transitionContext)) {
+            fromVC.view.alpha = 0
+
+            if let toReferenceViewFrame = toReferenceViewFrame {
+                self.transitionView?.frame = toReferenceViewFrame
+            } else {
+                self.transitionView?.alpha = 0
+            }
+
+            toVC.tabBarController?.tabBar.alpha = 1
+        } completion: { _ in
+            self.transitionView?.removeFromSuperview()
+            toReferenceView?.isHidden = false
+            fromReferenceView.isHidden = false
+
+            transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
+            self.toDelegate?.transitionDidEndWith(zoomAnimator: self)
+            self.fromDelegate?.transitionDidEndWith(zoomAnimator: self)
+        }
+    }
+}

Transitions/ZoomDismissalInteractionController.swift

@@ -0,0 +1,154 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import UIKit
+
+class ZoomDismissalInteractionController: NSObject {
+    var transitionContext: UIViewControllerContextTransitioning?
+    var animator: UIViewControllerAnimatedTransitioning?
+
+    var fromReferenceViewFrame: CGRect?
+    var toReferenceViewFrame: CGRect?
+
+    // swiftlint:disable:next function_body_length
+    func didPanWith(gestureRecognizer: UIPanGestureRecognizer) {
+        guard let transitionContext = self.transitionContext,
+            let animator = self.animator as? ZoomAnimator,
+            let transitionView = animator.transitionView,
+            let fromVC = transitionContext.viewController(forKey: .from),
+            let toVC = transitionContext.viewController(forKey: .to),
+            let fromReferenceView = animator.fromDelegate?.referenceView(for: animator),
+            let fromReferenceViewFrame = self.fromReferenceViewFrame
+            else { return }
+
+        let toReferenceView = animator.toDelegate?.referenceView(for: animator)
+
+        fromReferenceView.isHidden = true
+
+        let anchorPoint = CGPoint(x: fromReferenceViewFrame.midX, y: fromReferenceViewFrame.midY)
+        let dismissThreshold = fromReferenceViewFrame.height / 8
+        let translatedPoint = gestureRecognizer.translation(in: fromReferenceView)
+
+        let backgroundAlpha = backgroundAlphaFor(view: fromVC.view, withPanningVerticalDelta: translatedPoint.y)
+        let scale = scaleFor(view: fromVC.view, withPanningVerticalDelta: translatedPoint.y)
+
+        fromVC.view.alpha = backgroundAlpha
+
+        transitionView.transform = CGAffineTransform(scaleX: scale, y: scale)
+        let newCenter = CGPoint(
+            x: anchorPoint.x + translatedPoint.x,
+            y: anchorPoint.y + translatedPoint.y - transitionView.frame.height * (1 - scale) / 2.0)
+        transitionView.center = newCenter
+
+        toReferenceView?.isHidden = true
+
+        transitionContext.updateInteractiveTransition(1 - scale)
+
+        toVC.tabBarController?.tabBar.alpha = 1 - backgroundAlpha
+
+        if gestureRecognizer.state == .ended {
+            if abs(anchorPoint.y - newCenter.y) < dismissThreshold {
+                // cancel
+                UIView.animate(
+                    withDuration: 0.5,
+                    delay: 0,
+                    usingSpringWithDamping: 0.9,
+                    initialSpringVelocity: 0,
+                    options: []) {
+                    transitionView.frame = fromReferenceViewFrame
+                    fromVC.view.alpha = 1.0
+                    toVC.tabBarController?.tabBar.alpha = 0
+                } completion: { _ in
+                    toReferenceView?.isHidden = false
+                    fromReferenceView.isHidden = false
+                    transitionView.removeFromSuperview()
+                    animator.transitionView = nil
+                    transitionContext.cancelInteractiveTransition()
+                    transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
+                    animator.toDelegate?.transitionDidEndWith(zoomAnimator: animator)
+                    animator.fromDelegate?.transitionDidEndWith(zoomAnimator: animator)
+                    self.transitionContext = nil
+                }
+
+                return
+            }
+
+            // start animation
+            UIView.animate(
+                withDuration: .shortAnimationDuration) {
+                fromVC.view.alpha = 0
+
+                if let toReferenceViewFrame = self.toReferenceViewFrame {
+                    transitionView.frame = toReferenceViewFrame
+                } else {
+                    transitionView.alpha = 0
+                }
+
+                toVC.tabBarController?.tabBar.alpha = 1
+            } completion: { _ in
+                transitionView.removeFromSuperview()
+                toReferenceView?.isHidden = false
+                fromReferenceView.isHidden = false
+
+                self.transitionContext?.finishInteractiveTransition()
+                transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
+                animator.toDelegate?.transitionDidEndWith(zoomAnimator: animator)
+                animator.fromDelegate?.transitionDidEndWith(zoomAnimator: animator)
+                self.transitionContext = nil
+            }
+        }
+    }
+
+    func backgroundAlphaFor(view: UIView, withPanningVerticalDelta verticalDelta: CGFloat) -> CGFloat {
+        let startingAlpha: CGFloat = 1.0
+        let finalAlpha: CGFloat = 0.0
+        let totalAvailableAlpha = startingAlpha - finalAlpha
+
+        let maximumDelta = view.bounds.height / 4.0
+        let deltaAsPercentageOfMaximun = min(abs(verticalDelta) / maximumDelta, 1.0)
+
+        return startingAlpha - (deltaAsPercentageOfMaximun * totalAvailableAlpha)
+    }
+
+    func scaleFor(view: UIView, withPanningVerticalDelta verticalDelta: CGFloat) -> CGFloat {
+        let startingScale: CGFloat = 1.0
+        let finalScale: CGFloat = 0.5
+        let totalAvailableScale = startingScale - finalScale
+
+        let maximumDelta = view.bounds.height / 2.0
+        let deltaAsPercentageOfMaximun = min(abs(verticalDelta) / maximumDelta, 1.0)
+
+        return startingScale - (deltaAsPercentageOfMaximun * totalAvailableScale)
+    }
+}
+
+extension ZoomDismissalInteractionController: UIViewControllerInteractiveTransitioning {
+    func startInteractiveTransition(_ transitionContext: UIViewControllerContextTransitioning) {
+        guard let animator = animator as? ZoomAnimator else { return }
+
+        animator.fromDelegate?.transitionWillStartWith(zoomAnimator: animator)
+        animator.toDelegate?.transitionWillStartWith(zoomAnimator: animator)
+
+        self.transitionContext = transitionContext
+
+        let containerView = transitionContext.containerView
+
+        guard
+            let fromVC = transitionContext.viewController(forKey: .from),
+            let toVC = transitionContext.viewController(forKey: .to),
+            let fromReferenceViewFrame = animator.fromDelegate?.referenceViewFrameInTransitioningView(for: animator),
+            let fromReferenceView = animator.fromDelegate?.referenceView(for: animator)
+            else { return }
+
+        self.fromReferenceViewFrame = fromReferenceViewFrame
+        toReferenceViewFrame = animator.toDelegate?.referenceViewFrameInTransitioningView(for: animator)
+
+        containerView.insertSubview(toVC.view, belowSubview: fromVC.view)
+
+        if animator.transitionView == nil,
+           let transitionView = (fromReferenceView as? ZoomAnimatableView)?.transitionView() {
+            transitionView.frame = fromReferenceViewFrame
+            animator.transitionView = transitionView
+            containerView.addSubview(transitionView)
+        }
+    }
+}

Transitions/ZoomTransitionController.swift

@@ -0,0 +1,79 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import UIKit
+
+class ZoomTransitionController: NSObject {
+    var isInteractive = false
+
+    weak var fromDelegate: ZoomAnimatorDelegate?
+    weak var toDelegate: ZoomAnimatorDelegate?
+
+    private let animator = ZoomAnimator()
+    private let interactionController = ZoomDismissalInteractionController()
+
+    func didPanWith(gestureRecognizer: UIPanGestureRecognizer) {
+        interactionController.didPanWith(gestureRecognizer: gestureRecognizer)
+    }
+}
+
+extension ZoomTransitionController: UIViewControllerTransitioningDelegate {
+    func animationController(
+        forPresented presented: UIViewController,
+        presenting: UIViewController, source: UIViewController) -> UIViewControllerAnimatedTransitioning? {
+        presentingAnimator()
+    }
+
+    func animationController(forDismissed dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning? {
+        dismissingAnimator()
+    }
+
+    func interactionControllerForDismissal(
+        using animator: UIViewControllerAnimatedTransitioning) -> UIViewControllerInteractiveTransitioning? {
+        interactionController(animator: animator)
+    }
+
+}
+
+extension ZoomTransitionController: UINavigationControllerDelegate {
+    func navigationController(_ navigationController: UINavigationController,
+                              animationControllerFor operation: UINavigationController.Operation,
+                              from fromVC: UIViewController,
+                              to toVC: UIViewController) -> UIViewControllerAnimatedTransitioning? {
+        operation == .push ? presentingAnimator() : dismissingAnimator()
+    }
+
+    func navigationController(
+        _ navigationController: UINavigationController,
+        interactionControllerFor animationController: UIViewControllerAnimatedTransitioning)
+    -> UIViewControllerInteractiveTransitioning? {
+        interactionController(animator: animator)
+    }
+}
+
+private extension ZoomTransitionController {
+    private func presentingAnimator() -> UIViewControllerAnimatedTransitioning {
+        animator.isPresenting = true
+        animator.fromDelegate = fromDelegate
+        animator.toDelegate = toDelegate
+
+        return animator
+    }
+
+    private func dismissingAnimator() -> UIViewControllerAnimatedTransitioning {
+        animator.isPresenting = false
+        let tmp = fromDelegate
+        animator.fromDelegate = toDelegate
+        animator.toDelegate = tmp
+
+        return animator
+    }
+
+    private func interactionController(
+        animator: UIViewControllerAnimatedTransitioning) -> UIViewControllerInteractiveTransitioning? {
+        guard isInteractive else { return nil }
+
+        interactionController.animator = animator
+
+        return interactionController
+    }
+}

View Controllers/ImageNavigationController.swift

@@ -1,8 +1,11 @@
 // Copyright © 2020 Metabolist. All rights reserved.
 
+import AVFoundation
 import UIKit
 
 class ImageNavigationController: UINavigationController {
+    let transitionController = ZoomTransitionController()
+
     private let imagePageViewController: ImagePageViewController
 
     init(imagePageViewController: ImagePageViewController) {
@@ -21,5 +24,91 @@ class ImageNavigationController: UINavigationController {
 
         hidesBarsOnTap = true
         modalPresentationStyle = .fullScreen
+
+        let panGestureRecognizer = UIPanGestureRecognizer(
+            target: self,
+            action: #selector(didPanWith(gestureRecognizer:)))
+
+        panGestureRecognizer.delegate = self
+        view.addGestureRecognizer(panGestureRecognizer)
+
+        transitioningDelegate = transitionController
+        transitionController.toDelegate = self
+    }
+}
+
+extension ImageNavigationController {
+    var currentViewController: ImageViewController? {
+        imagePageViewController.viewControllers?.first as? ImageViewController
+    }
+
+    @objc func didPanWith(gestureRecognizer: UIPanGestureRecognizer) {
+        guard let currentViewController = currentViewController else { return }
+
+        switch gestureRecognizer.state {
+        case .began:
+            currentViewController.scrollView.isScrollEnabled = false
+            transitionController.isInteractive = true
+
+            presentingViewController?.dismiss(animated: true)
+        case .ended:
+            if transitionController.isInteractive {
+                currentViewController.scrollView.isScrollEnabled = true
+                transitionController.isInteractive = false
+                transitionController.didPanWith(gestureRecognizer: gestureRecognizer)
+            }
+        default:
+            if transitionController.isInteractive {
+                transitionController.didPanWith(gestureRecognizer: gestureRecognizer)
+            }
+        }
+    }
+}
+
+extension ImageNavigationController: ZoomAnimatorDelegate {
+    func transitionWillStartWith(zoomAnimator: ZoomAnimator) {
+
+    }
+
+    func transitionDidEndWith(zoomAnimator: ZoomAnimator) {
+
+    }
+
+    func referenceView(for zoomAnimator: ZoomAnimator) -> UIView? {
+        if currentViewController?.playerView.player != nil {
+            return currentViewController?.playerView
+        } else {
+            return currentViewController?.imageView
+        }
+    }
+
+    func referenceViewFrameInTransitioningView(for zoomAnimator: ZoomAnimator) -> CGRect? {
+        guard let currentViewController = currentViewController else { return .zero }
+
+        let rect: CGRect
+
+        if let image = currentViewController.imageView.image {
+            rect = AVMakeRect(aspectRatio: image.size, insideRect: currentViewController.imageView.frame)
+        } else if let item = currentViewController.playerView.player?.currentItem {
+            rect = AVMakeRect(aspectRatio: item.presentationSize, insideRect: currentViewController.playerView.frame)
+        } else {
+            return .zero
+        }
+
+        return currentViewController.scrollView.convert(rect, to: currentViewController.view)
+    }
+}
+
+extension ImageNavigationController: UIGestureRecognizerDelegate {
+    func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer,
+                           shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
+        if
+            let currentViewController = currentViewController,
+            otherGestureRecognizer == currentViewController.scrollView.panGestureRecognizer,
+            currentViewController.scrollView.contentOffset.y == 0 {
+            return true
+        }
+
+        return false
     }
 }

View Controllers/ImageViewController.swift

@@ -5,11 +5,12 @@ import UIKit
 import ViewModels
 
 class ImageViewController: UIViewController {
+    let scrollView = UIScrollView()
+    let imageView = AnimatedImageView()
+    let playerView = PlayerView()
+
     private let viewModel: AttachmentViewModel
-    private let scrollView = UIScrollView()
     private let contentView = UIView()
-    private let imageView = AnimatedImageView()
-    private let playerView = PlayerView()
     private let descriptionBackgroundView = UIVisualEffectView(effect: UIBlurEffect(style: .systemChromeMaterial))
     private let descriptionTextView = UITextView()
 
@@ -93,6 +94,7 @@ class ImageViewController: UIViewController {
 
         switch viewModel.attachment.type {
         case .image:
+            imageView.tag = viewModel.tag
             playerView.isHidden = true
             imageView.isHidden = false
             imageView.kf.indicatorType = .activity
@@ -111,6 +113,7 @@ class ImageViewController: UIViewController {
                     options: [.keepCurrentImageWhileLoading])
             })
         case .gifv:
+            playerView.tag = viewModel.tag
             playerView.isHidden = false
             imageView.isHidden = true
             let player = PlayerCache.shared.player(url: viewModel.attachment.url)

View Controllers/TableViewController.swift

@@ -13,6 +13,7 @@ class TableViewController: UITableViewController {
     private let webfingerIndicatorView = WebfingerIndicatorView()
     private var cancellables = Set<AnyCancellable>()
     private var cellHeightCaches = [CGFloat: [CollectionItem: CGFloat]]()
+    private var transitionViewTag = -1
 
     private lazy var dataSource: TableViewDataSource = {
         .init(tableView: tableView, viewModelProvider: viewModel.viewModel(indexPath:))
@@ -181,10 +182,36 @@ extension TableViewController: AVPlayerViewControllerDelegate {
     }
 }
 
-private extension TableViewController {
+extension TableViewController: ZoomAnimatorDelegate {
-    static let autoplayViews = [PlayerView](repeating: .init(), count: 4)
+    func transitionWillStartWith(zoomAnimator: ZoomAnimator) {
-    static var visibleVideoURLs = Set<URL>()
+        view.layoutIfNeeded()
 
+        guard let imageViewController = (presentedViewController as? ImageNavigationController)?.currentViewController
+        else { return }
+
+        if imageViewController.playerView.tag != 0 {
+            transitionViewTag = imageViewController.playerView.tag
+        } else if imageViewController.imageView.tag != 0 {
+            transitionViewTag = imageViewController.imageView.tag
+        }
+    }
+
+    func transitionDidEndWith(zoomAnimator: ZoomAnimator) {
+
+    }
+
+    func referenceView(for zoomAnimator: ZoomAnimator) -> UIView? {
+        tableView.visibleCells.compactMap { $0.viewWithTag(transitionViewTag) }.first
+    }
+
+    func referenceViewFrameInTransitioningView(for zoomAnimator: ZoomAnimator) -> CGRect? {
+        guard let referenceView = referenceView(for: zoomAnimator) else { return nil }
+
+        return tabBarController?.view.convert(referenceView.frame, from: referenceView.superview)
+    }
+}
+
+private extension TableViewController {
     var visibleLoadMoreViews: [LoadMoreView] {
         tableView.visibleCells.compactMap { $0.contentView as? LoadMoreView }
     }
@@ -315,6 +342,9 @@ private extension TableViewController {
                 statusViewModel: statusViewModel)
             let imageNavigationController = ImageNavigationController(imagePageViewController: imagePageViewController)
 
+            imageNavigationController.transitionController.fromDelegate = self
+            transitionViewTag = attachmentViewModel.tag
+
             present(imageNavigationController, animated: true)
         case .unknown:
             break

ViewModels/Sources/ViewModels/AttachmentViewModel.swift

@@ -6,12 +6,19 @@ import Mastodon
 public struct AttachmentViewModel {
     public let attachment: Attachment
 
-    init(attachment: Attachment) {
+    private let status: Status
+
+    init(attachment: Attachment, status: Status) {
         self.attachment = attachment
+        self.status = status
     }
 }
 
 public extension AttachmentViewModel {
+    var tag: Int {
+        attachment.id.appending(status.id).hashValue
+    }
+
     var aspectRatio: Double? {
         if
             let info = attachment.meta?.original,

ViewModels/Sources/ViewModels/StatusViewModel.swift

@@ -40,7 +40,7 @@ public struct StatusViewModel: CollectionItemViewModel {
             : statusService.status.account.displayName
         rebloggedByDisplayNameEmoji = statusService.status.account.emojis
         attachmentViewModels = statusService.status.displayStatus.mediaAttachments
-            .map(AttachmentViewModel.init(attachment:))
+            .map { AttachmentViewModel(attachment: $0, status: statusService.status) }
         pollOptionTitles = statusService.status.displayStatus.poll?.options.map { $0.title } ?? []
         pollEmoji = statusService.status.displayStatus.poll?.emojis ?? []
         events = eventsSubject.eraseToAnyPublisher()

Views/Status/StatusAttachmentView.swift

@@ -14,8 +14,12 @@ final class StatusAttachmentView: UIView {
         didSet {
             if playing {
                 play()
+                imageView.tag = 0
+                playerView.tag = viewModel.tag
             } else {
                 stop()
+                imageView.tag = viewModel.tag
+                playerView.tag = 0
             }
         }
     }
@@ -79,6 +83,7 @@ private extension StatusAttachmentView {
         imageView.translatesAutoresizingMaskIntoConstraints = false
         imageView.contentMode = .scaleAspectFill
         imageView.clipsToBounds = true
+        imageView.tag = viewModel.tag
 
         let blurEffect = UIBlurEffect(style: .systemUltraThinMaterial)
         let playView = UIVisualEffectView(effect: blurEffect)