Hide large image source view during expand/shrink animation

Tusker.xcodeproj/project.pbxproj

@@ -224,6 +224,7 @@
 		D6DD353D22F28CD000A9563A /* ContentWarningCopyMode.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6DD353C22F28CD000A9563A /* ContentWarningCopyMode.swift */; };
 		D6DD353F22F502EC00A9563A /* Preferences+Notification.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6DD353E22F502EC00A9563A /* Preferences+Notification.swift */; };
 		D6DFC69E242C490400ACC392 /* TrackpadScrollGestureRecognizer.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6DFC69D242C490400ACC392 /* TrackpadScrollGestureRecognizer.swift */; };
+		D6DFC6A0242C4CCC00ACC392 /* WeakArray.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6DFC69F242C4CCC00ACC392 /* WeakArray.swift */; };
 		D6E0DC8E216EDF1E00369478 /* Previewing.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6E0DC8D216EDF1E00369478 /* Previewing.swift */; };
 		D6E6F26321603F8B006A8599 /* CharacterCounter.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6E6F26221603F8B006A8599 /* CharacterCounter.swift */; };
 		D6E6F26521604242006A8599 /* CharacterCounterTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6E6F26421604242006A8599 /* CharacterCounterTests.swift */; };
@@ -512,6 +513,7 @@
 		D6DD353C22F28CD000A9563A /* ContentWarningCopyMode.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ContentWarningCopyMode.swift; sourceTree = "<group>"; };
 		D6DD353E22F502EC00A9563A /* Preferences+Notification.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Preferences+Notification.swift"; sourceTree = "<group>"; };
 		D6DFC69D242C490400ACC392 /* TrackpadScrollGestureRecognizer.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TrackpadScrollGestureRecognizer.swift; sourceTree = "<group>"; };
+		D6DFC69F242C4CCC00ACC392 /* WeakArray.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = WeakArray.swift; sourceTree = "<group>"; };
 		D6E0DC8D216EDF1E00369478 /* Previewing.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Previewing.swift; sourceTree = "<group>"; };
 		D6E6F26221603F8B006A8599 /* CharacterCounter.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CharacterCounter.swift; sourceTree = "<group>"; };
 		D6E6F26421604242006A8599 /* CharacterCounterTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CharacterCounterTests.swift; sourceTree = "<group>"; };
@@ -1213,6 +1215,7 @@
 				D6945C2E23AC47C3005C403C /* SavedDataManager.swift */,
 				D6028B9A2150811100F223B9 /* MastodonCache.swift */,
 				D6C693EE216192C2007D6A6D /* TuskerNavigationDelegate.swift */,
+				D6DFC69F242C4CCC00ACC392 /* WeakArray.swift */,
 				D6F1F84E2193B9BE00F5FE67 /* Caching */,
 				D6757A7A2157E00100721E32 /* XCallbackURL */,
 				D62D241E217AA46B005076CC /* Shortcuts */,
@@ -1707,6 +1710,7 @@
 				D6945C3223AC4D36005C403C /* HashtagTimelineViewController.swift in Sources */,
 				D647D92824257BEB0005044F /* AttachmentPreviewViewController.swift in Sources */,
 				D66362752137068A00C9CBA2 /* Visibility+Helpers.swift in Sources */,
+				D6DFC6A0242C4CCC00ACC392 /* WeakArray.swift in Sources */,
 				D6C693FC2162FE6F007D6A6D /* LoadingViewController.swift in Sources */,
 				D646C95A213B5D0500269FB5 /* LargeImageInteractionController.swift in Sources */,
 				D6A3BC7C232195C600FD64D5 /* ActionNotificationGroupTableViewCell.swift in Sources */,

Tusker/Screens/Attachment Gallery/GalleryViewController.swift

@@ -13,7 +13,7 @@ import AVKit
 class GalleryViewController: UIPageViewController, UIPageViewControllerDataSource, UIPageViewControllerDelegate, LargeImageAnimatableViewController {
 
     let attachments: [Attachment]
-    let sourcesInfo: [LargeImageViewController.SourceInfo?]
+    let sourceViews: WeakArray<UIImageView>
     let startIndex: Int
     
     let pages: [UIViewController]
@@ -26,12 +26,13 @@ class GalleryViewController: UIPageViewController, UIPageViewControllerDataSourc
         return index
     }
 
-    var animationSourceInfo: LargeImageViewController.SourceInfo? { sourcesInfo[currentIndex] }
+    var animationSourceView: UIImageView? { sourceViews[currentIndex] }
     var animationImage: UIImage? {
-        if let sourceImage = sourcesInfo[currentIndex]?.image {
+        if let page = pages[currentIndex] as? LoadingLargeImageViewController,
-            return sourceImage
+            let image = page.largeImageVC?.image {
+            return image
         } else {
-            return (pages[currentIndex] as? LoadingLargeImageViewController)?.largeImageVC?.image
+            return animationSourceView?.image
         }
     }
     var animationGifData: Data? {
@@ -59,9 +60,9 @@ class GalleryViewController: UIPageViewController, UIPageViewControllerDataSourc
         }
     }
     
-    init(attachments: [Attachment], sourcesInfo: [LargeImageViewController.SourceInfo?], startIndex: Int) {
+    init(attachments: [Attachment], sourceViews: [UIImageView?], startIndex: Int) {
         self.attachments = attachments
-        self.sourcesInfo = sourcesInfo
+        self.sourceViews = WeakArray(sourceViews)
         self.startIndex = startIndex
         
         self.pages = attachments.map {

Tusker/Screens/Large Image/LargeImageViewController.swift

@@ -11,10 +11,8 @@ import Gifu
 
 class LargeImageViewController: UIViewController, UIScrollViewDelegate, LargeImageAnimatableViewController {
 
-    typealias SourceInfo = (image: UIImage?, frame: CGRect, cornerRadius: CGFloat)
+    weak var animationSourceView: UIImageView?
-    
+    var animationImage: UIImage? { image ?? animationSourceView?.image }
-    var animationSourceInfo: SourceInfo?
-    var animationImage: UIImage? { animationSourceInfo?.image ?? image }
     var animationGifData: Data? { gifData }
     var dismissInteractionController: LargeImageInteractionController?
     
@@ -59,10 +57,10 @@ class LargeImageViewController: UIViewController, UIScrollViewDelegate, LargeIma
         return !controlsVisible
     }
     
-    init(image: UIImage, description: String?, sourceInfo: SourceInfo?) {
+    init(image: UIImage, description: String?, sourceView: UIImageView?) {
         self.image = image
         self.imageDescription = description
-        self.animationSourceInfo = sourceInfo
+        self.animationSourceView = sourceView
 
         super.init(nibName: "LargeImageViewController", bundle: nil)
         

Tusker/Screens/Large Image/LoadingLargeImageViewController.swift

@@ -35,8 +35,8 @@ class LoadingLargeImageViewController: UIViewController, LargeImageAnimatableVie
     
     var shrinkGestureEnabled = true
     
-    var animationSourceInfo: LargeImageViewController.SourceInfo?
+    weak var animationSourceView: UIImageView?
-    var animationImage: UIImage? { animationSourceInfo?.image ?? largeImageVC?.image }
+    var animationImage: UIImage? { largeImageVC?.image ?? animationSourceView?.image }
     var animationGifData: Data? { largeImageVC?.gifData }
     var dismissInteractionController: LargeImageInteractionController?
     
@@ -108,7 +108,7 @@ class LoadingLargeImageViewController: UIViewController, LargeImageAnimatableVie
     
     func createLargeImage(data: Data) {
         guard let image = UIImage(data: data) else { return }
-        largeImageVC = LargeImageViewController(image: image, description: imageDescription, sourceInfo: nil)
+        largeImageVC = LargeImageViewController(image: image, description: imageDescription, sourceView: animationSourceView)
         largeImageVC!.initialControlsVisible = initialControlsVisible
         largeImageVC!.shrinkGestureEnabled = false
         if url.pathExtension == "gif" {

Tusker/Screens/Large Image/Transitions/LargeImageExpandAnimationController.swift

@@ -10,12 +10,30 @@ import UIKit
 import Gifu
 
 protocol LargeImageAnimatableViewController: UIViewController {
-    var animationSourceInfo: LargeImageViewController.SourceInfo? { get }
+    var animationSourceView: UIImageView? { get }
     var animationImage: UIImage? { get }
     var animationGifData: Data? { get }
     var dismissInteractionController: LargeImageInteractionController? { get }
 }
 
+extension LargeImageAnimatableViewController {
+    func sourceViewFrame(in coordinateSpace: UIView) -> CGRect? {
+        guard let sourceView = animationSourceView else { return nil }
+        
+        var sourceFrame = sourceView.convert(sourceView.bounds, to: coordinateSpace)
+        if let scrollView = coordinateSpace as? UIScrollView {
+            let scale = scrollView.zoomScale
+            let width = sourceFrame.width * scale
+            let height = sourceFrame.height * scale
+            let x = sourceFrame.minX * scale - scrollView.contentOffset.x + scrollView.frame.minX
+            let y = sourceFrame.minY * scale - scrollView.contentOffset.y + scrollView.frame.minY
+            sourceFrame = CGRect(x: x, y: y, width: width, height: height)
+        }
+        
+        return sourceFrame
+    }
+}
+
 class LargeImageExpandAnimationController: NSObject, UIViewControllerAnimatedTransitioning {
     
     func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
@@ -32,12 +50,16 @@ class LargeImageExpandAnimationController: NSObject, UIViewControllerAnimatedTra
         containerView.addSubview(toVC.view)
 
         let finalVCFrame = transitionContext.finalFrame(for: toVC)
-        guard let sourceInfo = toVC.animationSourceInfo,
+        guard let sourceView = toVC.animationSourceView,
+            let sourceFrame = toVC.sourceViewFrame(in: fromVC.view),
             let image = toVC.animationImage else {
                 toVC.view.frame = finalVCFrame
                 transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
                 return
         }
+        
+        // use alpha, becaus isHidden makes stack views re-layout
+        sourceView.alpha = 0
 
         var finalFrameSize = finalVCFrame.inset(by: fromVC.view.safeAreaInsets).size
         let newWidth = finalFrameSize.width / image.size.width
@@ -49,13 +71,14 @@ class LargeImageExpandAnimationController: NSObject, UIViewControllerAnimatedTra
         }
         let finalFrame = CGRect(origin: CGPoint(x: finalVCFrame.midX - finalFrameSize.width / 2, y: finalVCFrame.midY - finalFrameSize.height / 2), size: finalFrameSize)
 
-        let imageView = GIFImageView(frame: sourceInfo.frame)
+        let imageView = GIFImageView(frame: sourceFrame)
         imageView.image = image
         if let gifData = toVC.animationGifData {
             imageView.animate(withGIFData: gifData)
         }
         imageView.contentMode = .scaleAspectFill
-        imageView.layer.cornerRadius = sourceInfo.cornerRadius
+        imageView.layer.cornerRadius = sourceView.layer.cornerRadius
+        imageView.layer.maskedCorners = sourceView.layer.maskedCorners
         imageView.layer.masksToBounds = true
         
         let blackView = UIView(frame: finalVCFrame)
@@ -84,6 +107,9 @@ class LargeImageExpandAnimationController: NSObject, UIViewControllerAnimatedTra
             fromVC.view.isHidden = false
             blackView.removeFromSuperview()
             imageView.removeFromSuperview()
+            
+            sourceView.alpha = 1
+
             transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
         })
     }

Tusker/Screens/Large Image/Transitions/LargeImageShrinkAnimationController.swift

@@ -27,12 +27,15 @@ class LargeImageShrinkAnimationController: NSObject, UIViewControllerAnimatedTra
                 return
         }
         
-        guard let sourceInfo = fromVC.animationSourceInfo,
+        guard let sourceView = fromVC.animationSourceView,
+            let sourceFrame = fromVC.sourceViewFrame(in: toVC.view),
             let image = fromVC.animationImage else {
                 transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
                 return
         }
 
+        // use alpha, becaus isHidden makes stack views re-layout
+        sourceView.alpha = 0
 
         let containerView = transitionContext.containerView
         
@@ -66,8 +69,9 @@ class LargeImageShrinkAnimationController: NSObject, UIViewControllerAnimatedTra
         
         let duration = transitionDuration(using: transitionContext)
         UIView.animate(withDuration: duration, animations: {
-            imageView.frame = sourceInfo.frame
+            imageView.frame = sourceFrame
-            imageView.layer.cornerRadius = sourceInfo.cornerRadius
+            imageView.layer.cornerRadius = sourceView.layer.cornerRadius
+            imageView.layer.maskedCorners = sourceView.layer.maskedCorners
             blackView.alpha = 0
         }, completion: { _ in
             blackView.removeFromSuperview()
@@ -75,6 +79,9 @@ class LargeImageShrinkAnimationController: NSObject, UIViewControllerAnimatedTra
             if transitionContext.transitionWasCancelled {
                 toVC.view.removeFromSuperview()
             }
+            
+            sourceView.alpha = 1
+
             transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
         })
     }

Tusker/TuskerNavigationDelegate.swift

@@ -150,30 +150,15 @@ extension TuskerNavigationDelegate where Self: UIViewController {
         vc.presentationController?.delegate = compose
         present(vc, animated: true)
     }
-    
+
-    private func sourceViewInfo(_ sourceView: UIImageView?) -> LargeImageViewController.SourceInfo? {
-        guard let sourceView = sourceView else { return nil }
-        
-        var sourceFrame = sourceView.convert(sourceView.bounds, to: view)
-        if let scrollView = view as? UIScrollView {
-            let scale = scrollView.zoomScale
-            let width = sourceFrame.width * scale
-            let height = sourceFrame.height * scale
-            let x = sourceFrame.minX * scale - scrollView.contentOffset.x + scrollView.frame.minX
-            let y = sourceFrame.minY * scale - scrollView.contentOffset.y + scrollView.frame.minY
-            sourceFrame = CGRect(x: x, y: y, width: width, height: height)
-        }
-        return (image: sourceView.image, frame: sourceFrame, cornerRadius: sourceView.layer.cornerRadius)
-    }
-    
     func largeImage(_ image: UIImage, description: String?, sourceView: UIImageView) -> LargeImageViewController {
-        let vc = LargeImageViewController(image: image, description: description, sourceInfo: sourceViewInfo(sourceView))
+        let vc = LargeImageViewController(image: image, description: description, sourceView: sourceView)
         vc.transitioningDelegate = self
         return vc
     }
     
     func largeImage(gifData: Data, description: String?, sourceView: UIImageView) -> LargeImageViewController {
-        let vc = LargeImageViewController(image: UIImage(data: gifData)!, description: description, sourceInfo: sourceViewInfo(sourceView))
+        let vc = LargeImageViewController(image: UIImage(data: gifData)!, description: description, sourceView: sourceView)
         vc.transitioningDelegate = self
         vc.gifData = gifData
         return vc
@@ -189,7 +174,7 @@ extension TuskerNavigationDelegate where Self: UIViewController {
     
     func loadingLargeImage(url: URL, cache: ImageCache, description: String?, animatingFrom sourceView: UIImageView) -> LoadingLargeImageViewController {
         let vc = LoadingLargeImageViewController(url: url, cache: cache, imageDescription: description)
-        vc.animationSourceInfo = sourceViewInfo(sourceView)
+        vc.animationSourceView = sourceView
         vc.transitioningDelegate = self
         return vc
     }
@@ -199,8 +184,7 @@ extension TuskerNavigationDelegate where Self: UIViewController {
     }
     
     func gallery(attachments: [Attachment], sourceViews: [UIImageView?], startIndex: Int) -> GalleryViewController {
-        let sourcesInfo = sourceViews.map(sourceViewInfo)
+        let vc = GalleryViewController(attachments: attachments, sourceViews: sourceViews, startIndex: startIndex)
-        let vc = GalleryViewController(attachments: attachments, sourcesInfo: sourcesInfo, startIndex: startIndex)
         vc.transitioningDelegate = self
         return vc
     }

Tusker/WeakArray.swift

@@ -0,0 +1,40 @@
+//
+//  WeakArray.swift
+//  Tusker
+//
+//  Created by Shadowfacts on 3/25/20.
+//  Copyright © 2020 Shadowfacts. All rights reserved.
+//
+
+import Foundation
+
+fileprivate class WeakWrapper<T: AnyObject> {
+    weak var value: T?
+    
+    init(_ value: T?) {
+        self.value = value
+    }
+}
+
+struct WeakArray<Element: AnyObject>: Collection {
+    private var array: [WeakWrapper<Element>]
+    
+    var startIndex: Int { array.startIndex }
+    var endIndex: Int { array.endIndex }
+    
+    init(_ elements: [Element]) {
+        array = elements.map { WeakWrapper($0) }
+    }
+    
+    init(_ elements: [Element?]) {
+        array = elements.map { WeakWrapper($0) }
+    }
+    
+    subscript(_ index: Int) -> Element? {
+        return array[index].value
+    }
+    
+    func index(after i: Int) -> Int {
+        return array.index(after: i)
+    }
+}