Match gif playback progress through animation

Closes #8

.gitmodules

@@ -1,6 +1,3 @@
-[submodule "Gifu"]
-	path = Gifu
-	url = git://github.com/kaishin/Gifu.git
 [submodule "Embassy"]
 	path = Embassy
 	url = https://github.com/envoy/Embassy.git

Gifu

@@ -1 +0,0 @@
-Subproject commit 9b1a6461aa3b5f66cb0ed3a50c5523db0b4fb007

Pachyderm/Utilities/CharacterCounter.swift

@@ -13,12 +13,12 @@ public struct CharacterCounter {
     static let linkDetector = try! NSDataDetector(types: NSTextCheckingResult.CheckingType.link.rawValue)
     static let mention = try! NSRegularExpression(pattern: "(@[a-z0-9_]+)(?:@[a-z0-9\\-\\.]+[a-z0-9]+)?", options: .caseInsensitive)
     
-    public static func count(text: String) -> Int {
+    public static func count(text: String, for instance: Instance? = nil) -> Int {
         let mentionsRemoved = removeMentions(in: text)
         var count = mentionsRemoved.count
         for match in linkDetector.matches(in: mentionsRemoved, options: [], range: NSRange(location: 0, length: mentionsRemoved.utf16.count)) {
             count -= match.range.length
-            count += 23 // Mastodon link length
+            count += instance?.configuration?.statuses.charactersReservedPerURL ?? 23 // default Mastodon link length
         }
         return count
     }

Tusker.xcodeproj/project.pbxproj

@@ -274,8 +274,6 @@
 		D6B81F3C2560365300F6E31D /* RefreshableViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6B81F3B2560365300F6E31D /* RefreshableViewController.swift */; };
 		D6B81F442560390300F6E31D /* MenuController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6B81F432560390300F6E31D /* MenuController.swift */; };
 		D6B8DB342182A59300424AF7 /* UIAlertController+Visibility.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6B8DB332182A59300424AF7 /* UIAlertController+Visibility.swift */; };
-		D6BC874521961F73006163F1 /* Gifu.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = D6BC874421961F73006163F1 /* Gifu.framework */; };
-		D6BC874621961F73006163F1 /* Gifu.framework in Embed Frameworks */ = {isa = PBXBuildFile; fileRef = D6BC874421961F73006163F1 /* Gifu.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
 		D6BC8748219738E1006163F1 /* EnhancedTableViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6BC8747219738E1006163F1 /* EnhancedTableViewController.swift */; };
 		D6BC9DB1232C61BC002CA326 /* NotificationsPageViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6BC9DB0232C61BC002CA326 /* NotificationsPageViewController.swift */; };
 		D6BC9DB3232D4C07002CA326 /* WellnessPrefsView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6BC9DB2232D4C07002CA326 /* WellnessPrefsView.swift */; };
@@ -309,6 +307,7 @@
 		D6D4DDE5212518A200E1C4BB /* TuskerTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6D4DDE4212518A200E1C4BB /* TuskerTests.swift */; };
 		D6D4DDF0212518A200E1C4BB /* TuskerUITests.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6D4DDEF212518A200E1C4BB /* TuskerUITests.swift */; };
 		D6DD2A3F273C1F4900386A6C /* ComposeAttachmentImage.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6DD2A3E273C1F4900386A6C /* ComposeAttachmentImage.swift */; };
+		D6DD2A45273D6C5700386A6C /* GIFImageView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6DD2A44273D6C5700386A6C /* GIFImageView.swift */; };
 		D6DD353D22F28CD000A9563A /* ContentWarningCopyMode.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6DD353C22F28CD000A9563A /* ContentWarningCopyMode.swift */; };
 		D6DD353F22F502EC00A9563A /* Preferences+Notification.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6DD353E22F502EC00A9563A /* Preferences+Notification.swift */; };
 		D6DEA0DE268400C300FE896A /* ConfirmLoadMoreTableViewCell.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6DEA0DC268400C300FE896A /* ConfirmLoadMoreTableViewCell.swift */; };
@@ -406,7 +405,6 @@
 			dstSubfolderSpec = 10;
 			files = (
 				D61099C12144B0CC00432DC2 /* Pachyderm.framework in Embed Frameworks */,
-				D6BC874621961F73006163F1 /* Gifu.framework in Embed Frameworks */,
 			);
 			name = "Embed Frameworks";
 			runOnlyForDeploymentPostprocessing = 0;
@@ -681,7 +679,6 @@
 		D6B81F3B2560365300F6E31D /* RefreshableViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = RefreshableViewController.swift; sourceTree = "<group>"; };
 		D6B81F432560390300F6E31D /* MenuController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MenuController.swift; sourceTree = "<group>"; };
 		D6B8DB332182A59300424AF7 /* UIAlertController+Visibility.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "UIAlertController+Visibility.swift"; sourceTree = "<group>"; };
-		D6BC874421961F73006163F1 /* Gifu.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; path = Gifu.framework; sourceTree = BUILT_PRODUCTS_DIR; };
 		D6BC8747219738E1006163F1 /* EnhancedTableViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = EnhancedTableViewController.swift; sourceTree = "<group>"; };
 		D6BC9DB0232C61BC002CA326 /* NotificationsPageViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NotificationsPageViewController.swift; sourceTree = "<group>"; };
 		D6BC9DB2232D4C07002CA326 /* WellnessPrefsView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = WellnessPrefsView.swift; sourceTree = "<group>"; };
@@ -721,6 +718,7 @@
 		D6D4DDEF212518A200E1C4BB /* TuskerUITests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TuskerUITests.swift; sourceTree = "<group>"; };
 		D6D4DDF1212518A200E1C4BB /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
 		D6DD2A3E273C1F4900386A6C /* ComposeAttachmentImage.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ComposeAttachmentImage.swift; sourceTree = "<group>"; };
+		D6DD2A44273D6C5700386A6C /* GIFImageView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = GIFImageView.swift; sourceTree = "<group>"; };
 		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>"; };
 		D6DEA0DC268400C300FE896A /* ConfirmLoadMoreTableViewCell.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ConfirmLoadMoreTableViewCell.swift; sourceTree = "<group>"; };
@@ -780,7 +778,6 @@
 				D61099C02144B0CC00432DC2 /* Pachyderm.framework in Frameworks */,
 				D6B0539F23BD2BA300A066FA /* SheetController in Frameworks */,
 				D69CCBBF249E6EFD000AF167 /* CrashReporter in Frameworks */,
-				D6BC874521961F73006163F1 /* Gifu.framework in Frameworks */,
 				D60CFFDB24A290BA00D00083 /* SwiftSoup in Frameworks */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
@@ -1480,6 +1477,7 @@
 				D6969E9F240C8384002843CE /* EmojiLabel.swift */,
 				D67C1794266D57D10070F250 /* FastAccountSwitcherIndicatorView.swift */,
 				D6EAE0DA2550CC8A002DB0AC /* FocusableTextField.swift */,
+				D6DD2A44273D6C5700386A6C /* GIFImageView.swift */,
 				D641C77E213DC78A004B4513 /* InlineTextAttachment.swift */,
 				D620483323D3801D008A63EF /* LinkTextView.swift */,
 				D68E6F58253C9969001A1B4C /* MultiSourceEmojiLabel.swift */,
@@ -1546,7 +1544,6 @@
 		D6D4DDC3212518A000E1C4BB = {
 			isa = PBXGroup;
 			children = (
-				D6BC874421961F73006163F1 /* Gifu.framework */,
 				D61099AC2144B0CC00432DC2 /* Pachyderm */,
 				D61099B92144B0CC00432DC2 /* PachydermTests */,
 				D6D4DDCE212518A000E1C4BB /* Tusker */,
@@ -2191,6 +2188,7 @@
 				D69693F42585941A00F4E116 /* UIWindowSceneDelegate+Close.swift in Sources */,
 				D6C143DA253510F4007DC240 /* ComposeEmojiTextField.swift in Sources */,
 				D6DD2A3F273C1F4900386A6C /* ComposeAttachmentImage.swift in Sources */,
+				D6DD2A45273D6C5700386A6C /* GIFImageView.swift in Sources */,
 				0427033822B30F5F000D31B6 /* BehaviorPrefsView.swift in Sources */,
 				D627943923A553B600D38C68 /* UnbookmarkStatusActivity.swift in Sources */,
 				D64D0AAD2128D88B005A6F37 /* LocalData.swift in Sources */,

Tusker.xcworkspace/contents.xcworkspacedata

@@ -7,9 +7,6 @@
    <FileRef
       location = "group:BlankSlate.xcappdata">
    </FileRef>
-   <FileRef
-      location = "group:Gifu/Gifu.xcodeproj">
-   </FileRef>
    <FileRef
       location = "group:Embassy/Embassy.xcodeproj">
    </FileRef>

Tusker/ImageGrayscalifier.swift

@@ -17,6 +17,7 @@ struct ImageGrayscalifier {
     static func convertIfNecessary(url: URL?, image: UIImage) -> UIImage? {
         if Preferences.shared.grayscaleImages,
            let source = image.cgImage {
+            // todo: should this return the original image if conversion fails?
             return convert(url: url, cgImage: source)
         } else {
             return image

Tusker/Screens/Attachment Gallery/AttachmentPreviewViewController.swift

@@ -8,14 +8,15 @@
 
 import UIKit
 import Pachyderm
-import Gifu
 
 class AttachmentPreviewViewController: UIViewController {
 
-    let attachment: Attachment
+    private let attachment: Attachment
+    private let sourceView: AttachmentView
     
-    init(attachment: Attachment) {
+    init(sourceView: AttachmentView) {
-        self.attachment = attachment
+        self.attachment = sourceView.attachment
+        self.sourceView = sourceView
 
         super.init(nibName: nil, bundle: nil)
     }
@@ -30,7 +31,9 @@ class AttachmentPreviewViewController: UIViewController {
             let imageView: UIImageView
             if attachment.url.pathExtension == "gif" {
                 let gifView = GIFImageView(image: image)
-                gifView.animate(withGIFData: data)
+                let controller = sourceView.gifController ?? GIFController(gifData: data)
+                controller.attach(to: gifView)
+                controller.startAnimating()
                 imageView = gifView
             } else {
                 imageView = UIImageView(image: image)

Tusker/Screens/Attachment Gallery/GalleryViewController.swift

@@ -41,14 +41,6 @@ class GalleryViewController: UIPageViewController, UIPageViewControllerDataSourc
             return animationSourceView?.image
         }
     }
-    var animationGifData: Data? {
-        let attachment = attachments[currentIndex]
-        if attachment.url.pathExtension == "gif" {
-            return ImageCache.attachments.getData(attachment.url)
-        } else {
-            return nil
-        }
-    }
     var dismissInteractionController: LargeImageInteractionController?
     
     var isInteractivelyAnimatingDismissal: Bool = false {

Tusker/Screens/Compose/ComposeView.swift

@@ -30,7 +30,7 @@ struct ComposeView: View {
     var charactersRemaining: Int {
         let limit = mastodonController.instance?.maxStatusCharacters ?? 500
         let cwCount = draft.contentWarningEnabled ? draft.contentWarning.count : 0
-        return limit - (cwCount + CharacterCounter.count(text: draft.text))
+        return limit - (cwCount + CharacterCounter.count(text: draft.text, for: mastodonController.instance))
     }
     
     var requiresAttachmentDescriptions: Bool {

Tusker/Screens/Large Image/LargeImageContentView.swift

@@ -7,24 +7,18 @@
 //
 
 import UIKit
-import Gifu
 import Pachyderm
 import AVFoundation
 
 protocol LargeImageContentView: UIView {
     var animationImage: UIImage? { get }
-    var animationGifData: Data? { get }
     var activityItemsForSharing: [Any] { get }
     func grayscaleStateChanged()
 }
 
-class LargeImageImageContentView: UIImageView, GIFAnimatable, LargeImageContentView {
+class LargeImageImageContentView: GIFImageView, LargeImageContentView {
-    lazy var animator: Animator? = {
-        return Animator(withDelegate: self)
-    }()
     
     var animationImage: UIImage? { image! }
-    let animationGifData: Data?
     
     var activityItemsForSharing: [Any] {
         [image!]
@@ -32,34 +26,18 @@ class LargeImageImageContentView: UIImageView, GIFAnimatable, LargeImageContentV
     
     private var sourceData: Data?
     
-    convenience init(sourceData data: Data, isGif: Bool) {
-        self.init(image: UIImage(data: data)!, gifData: isGif ? data : nil)
-        
-        self.sourceData = data
-    }
-    
-    init(image: UIImage, gifData: Data?) {
-        self.animationGifData = gifData
     
+    init(image: UIImage) {
         super.init(image: image)
         
         contentMode = .scaleAspectFit
         
-        if let data = gifData {
-            self.animate(withGIFData: data)
-        }
     }
     
     required init?(coder: NSCoder) {
         fatalError("init(coder:) has not been implemented")
     }
     
-    override public func display(_ layer: CALayer) {
-        super.display(layer)
-        
-        updateImageIfNeeded()
-    }
-    
     func grayscaleStateChanged() {
         guard let data = sourceData else {
             return
@@ -78,9 +56,35 @@ class LargeImageImageContentView: UIImageView, GIFAnimatable, LargeImageContentV
     }
 }
 
+class LargeImageGifContentView: GIFImageView, LargeImageContentView {
+    var animationImage: UIImage? { image }
+    
+    var activityItemsForSharing: [Any] {
+        // todo: should gifs share the data?
+        [image].compactMap { $0 }
+    }
+    
+    init(gifController: GIFController) {
+        super.init(image: gifController.lastFrame?.image)
+        
+        contentMode = .scaleAspectFit
+        
+        gifController.attach(to: self)
+        // todo: doing this in the init feels wrong
+        gifController.startAnimating()
+    }
+    
+    required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+    
+    func grayscaleStateChanged() {
+        // todo
+    }
+}
+
 class LargeImageGifvContentView: GifvAttachmentView, LargeImageContentView {
     private(set) var animationImage: UIImage?
-    var animationGifData: Data? { nil }
     var activityItemsForSharing: [Any] {
         // todo: what should we share for gifvs?
         // some SO posts indicate that just sharing a URL to the video should work, but that may need to be a local URL?

Tusker/Screens/Large Image/LargeImageViewController.swift

@@ -13,7 +13,6 @@ class LargeImageViewController: UIViewController, UIScrollViewDelegate, LargeIma
     weak var animationSourceView: UIImageView?
     var largeImageController: LargeImageViewController? { self }
     var animationImage: UIImage? { contentView.animationImage }
-    var animationGifData: Data? { contentView.animationGifData }
     var dismissInteractionController: LargeImageInteractionController?
     
     @IBOutlet weak var scrollView: UIScrollView!

Tusker/Screens/Large Image/LoadingLargeImageViewController.swift

@@ -40,7 +40,6 @@ class LoadingLargeImageViewController: UIViewController, LargeImageAnimatableVie
     weak var animationSourceView: UIImageView?
     var largeImageController: LargeImageViewController? { largeImageVC }
     var animationImage: UIImage? { largeImageVC?.animationImage ?? animationSourceView?.image }
-    var animationGifData: Data? { largeImageVC?.animationGifData }
     var dismissInteractionController: LargeImageInteractionController?
     
     var isInteractivelyAnimatingDismissal: Bool = false {
@@ -93,6 +92,8 @@ class LoadingLargeImageViewController: UIViewController, LargeImageAnimatableVie
         
         // always load full resolution from disk for large image, in case the cache is scaled
         if let entry = cache.get(url, loadOriginal: true) {
+            // todo: if load original is true, is there any way entry.data could be nil?
+            // feels like the data param of createLargeImage shouldn't be optional
             createLargeImage(data: entry.data, image: entry.image, url: url)
         } else {
             createPreview()
@@ -126,19 +127,31 @@ class LoadingLargeImageViewController: UIViewController, LargeImageAnimatableVie
         guard !loaded else { return }
         loaded = true
         
-        if let transformedImage = ImageGrayscalifier.convertIfNecessary(url: url, image: image) {
+        let content: LargeImageContentView
-            let gifData = url.pathExtension == "gif" ? data : nil
+        
-            createLargeImage(image: transformedImage, gifData: gifData)
+        // todo: p sure grayscaling gifs has never worked
+        if url.pathExtension == "gif", let data = data {
+            // todo: pulling the gif controller out of the source view feels icky
+            // is it possible for the source view's gif controller to have different data than we just got?
+            // should this be a property set by the animation controller instead?
+            let gifController = (animationSourceView as? GIFImageView)?.gifController ?? GIFController(gifData: data)
+            content = LargeImageGifContentView(gifController: gifController)
+        } else {
+            if let transformedImage = ImageGrayscalifier.convertIfNecessary(url: url, image: image) {
+                content = LargeImageImageContentView(image: transformedImage)
+            } else {
+                content = LargeImageImageContentView(image: image)
+            }
         }
+        
+        setContent(content)
     }
     
-    private func createLargeImage(image: UIImage, gifData: Data?) {
+    private func setContent(_ content: LargeImageContentView) {
-        let imageView = LargeImageImageContentView(image: image, gifData: gifData)
-        
         if let existing = largeImageVC {
-            existing.contentView = imageView
+            existing.contentView = content
         } else {
-            largeImageVC = LargeImageViewController(contentView: imageView, description: imageDescription, sourceView: animationSourceView)
+            largeImageVC = LargeImageViewController(contentView: content, description: imageDescription, sourceView: animationSourceView)
             largeImageVC!.initialControlsVisible = initialControlsVisible
             largeImageVC!.shrinkGestureEnabled = false
             embedChild(largeImageVC!)
@@ -154,7 +167,7 @@ class LoadingLargeImageViewController: UIViewController, LargeImageAnimatableVie
            let grayscale = ImageGrayscalifier.convert(url: nil, cgImage: source) {
             image = grayscale
         }
-        self.createLargeImage(image: image, gifData: nil)
+        setContent(LargeImageImageContentView(image: image))
     }
     
 }

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

@@ -7,13 +7,11 @@
 //
 
 import UIKit
-import Gifu
 
 protocol LargeImageAnimatableViewController: UIViewController {
     var animationSourceView: UIImageView? { get }
     var largeImageController: LargeImageViewController? { get }
     var animationImage: UIImage? { get }
-    var animationGifData: Data? { get }
     var dismissInteractionController: LargeImageInteractionController? { get }
     var isInteractivelyAnimatingDismissal: Bool { get set }
 }
@@ -87,8 +85,8 @@ class LargeImageExpandAnimationController: NSObject, UIViewControllerAnimatedTra
 
         let imageView = GIFImageView(frame: sourceFrame)
         imageView.image = image
-        if let gifData = toVC.animationGifData {
+        if let gifController = (sourceView as? GIFImageView)?.gifController {
-            imageView.animate(withGIFData: gifData)
+            gifController.attach(to: imageView)
         }
         imageView.contentMode = .scaleAspectFill
         imageView.layer.cornerRadius = sourceView.layer.cornerRadius

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

@@ -7,7 +7,6 @@
 //
 
 import UIKit
-import Gifu
 
 class LargeImageShrinkAnimationController: NSObject, UIViewControllerAnimatedTransitioning {
     
@@ -57,8 +56,10 @@ class LargeImageShrinkAnimationController: NSObject, UIViewControllerAnimatedTra
 
         let imageView = GIFImageView(frame: originalFrame)
         imageView.image = image
-        if let gifData = fromVC.animationGifData {
+        if let gifController = (sourceView as? GIFImageView)?.gifController {
-            imageView.animate(withGIFData: gifData)
+            gifController.attach(to: imageView)
+            // todo: this might not be necessary, the large image content view should have started it
+            gifController.startAnimating()
         }
         imageView.contentMode = .scaleAspectFill
         imageView.layer.cornerRadius = 0

Tusker/Views/Attachments/AttachmentView.swift

@@ -8,7 +8,6 @@
 
 import UIKit
 import Pachyderm
-import Gifu
 import AVFoundation
 
 protocol AttachmentViewDelegate: AnyObject {
@@ -16,7 +15,7 @@ protocol AttachmentViewDelegate: AnyObject {
     func attachmentViewPresent(_ vc: UIViewController, animated: Bool)
 }
 
-class AttachmentView: UIImageView, GIFAnimatable {
+class AttachmentView: GIFImageView {
     
     weak var delegate: AttachmentViewDelegate?
 
@@ -30,22 +29,12 @@ class AttachmentView: UIImageView, GIFAnimatable {
     private var attachmentRequest: ImageCache.Request?
     private var source: Source?
     
-    var gifData: Data? {
-        switch source {
-        case let .gifData(_, data):
-            return data
-        default:
-            return nil
-        }
-    }
     private var autoplayGifs: Bool {
         Preferences.shared.automaticallyPlayGifs && !ProcessInfo.processInfo.isLowPowerModeEnabled
     }
     
     private var isGrayscale = false
 
-    public lazy var animator: Animator? = Animator(withDelegate: self)
-
     init(attachment: Attachment, index: Int, expectedSize: CGSize) {
         super.init(image: nil)
         commonInit()
@@ -94,11 +83,13 @@ class AttachmentView: UIImageView, GIFAnimatable {
         // NSProcessInfoPowerStateDidChange is sometimes fired on a background thread
         DispatchQueue.main.async {
             if self.attachment.kind == .image,
-               let gifData = self.gifData {
+               let gifController = self.gifController {
                 if self.autoplayGifs && !self.isAnimatingGIF {
-                    self.animate(withGIFData: gifData)
+                    gifController.attach(to: self)
+                    gifController.startAnimating()
                 } else if !self.autoplayGifs && self.isAnimatingGIF {
-                    self.stopAnimatingGIF()
+                    // detach instead of stopping so that any other attached gif views keep animating
+                    self.detachGIFController()
                 }
             } else if self.attachment.kind == .gifv,
                       let gifvView = self.gifvView {
@@ -169,13 +160,18 @@ class AttachmentView: UIImageView, GIFAnimatable {
             }
             if self.attachment.url.pathExtension == "gif" {
                 self.source = .gifData(attachmentURL, data)
-                if self.autoplayGifs {
+                let controller = GIFController(gifData: data)
-                    DispatchQueue.main.async {
+                DispatchQueue.main.async {
-                        self.animate(withGIFData: data)
+                    controller.attach(to: self)
+                    if self.autoplayGifs {
+                        controller.startAnimating()
                     }
-                } else {
+                }
+                
+                if !self.autoplayGifs {
                     self.displayImage()
                 }
+                
             } else {
                 self.source = .imageData(attachmentURL, data)
                 self.displayImage()
@@ -293,12 +289,6 @@ class AttachmentView: UIImageView, GIFAnimatable {
         }
     }
     
-    override func display(_ layer: CALayer) {
-        super.display(layer)
-        
-        updateImageIfNeeded()
-    }
-    
     func showGallery() {
         if let delegate = delegate,
            let gallery = delegate.attachmentViewGallery(startingAt: index) {
@@ -331,7 +321,7 @@ extension AttachmentView: UIContextMenuInteractionDelegate {
     func contextMenuInteraction(_ interaction: UIContextMenuInteraction, configurationForMenuAtLocation location: CGPoint) -> UIContextMenuConfiguration? {
         return UIContextMenuConfiguration(identifier: nil, previewProvider: { () -> UIViewController? in
             if self.attachment.kind == .image {
-                return AttachmentPreviewViewController(attachment: self.attachment)
+                return AttachmentPreviewViewController(sourceView: self)
             } else if self.attachment.kind == .gifv {
                 let vc = GifvAttachmentViewController(attachment: self.attachment)
                 vc.preferredContentSize = self.image?.size ?? .zero

Tusker/Views/GIFImageView.swift

@@ -0,0 +1,91 @@
+//
+//  GIFImageView.swift
+//  Tusker
+//
+//  Created by Shadowfacts on 11/11/21.
+//  Copyright © 2021 Shadowfacts. All rights reserved.
+//
+
+import UIKit
+
+class GIFImageView: UIImageView {
+    
+    fileprivate(set) var gifController: GIFController? = nil
+    var isAnimatingGIF: Bool { gifController?.state == .playing }
+    
+    /// Detaches the current GIF controller from this view.
+    /// If this view is the GIF controller's only one, it will stop itself.
+    func detachGIFController() {
+        gifController?.detach(from: self)
+    }
+    
+}
+
+/// A `GIFController` controls the animation of one or more `GIFImageView`s.
+class GIFController {
+    
+    // GIFImageView strongly holds the controller so that when the last view detaches, the controller is freed
+    private var imageViews = WeakArray<GIFImageView>()
+    
+    private(set) var gifData: Data
+    private(set) var state: State = .stopped
+    private(set) var lastFrame: (image: UIImage, index: Int)? = nil
+    
+    init(gifData: Data) {
+        self.gifData = gifData
+    }
+    
+    /// Attaches another view to this controller, letting it play back alongside the others.
+    /// Immediately brings it into sync with the others, setting the last frame if there was one.
+    func attach(to view: GIFImageView) {
+        imageViews.append(view)
+        view.gifController = self
+        
+        if let lastFrame = lastFrame {
+            view.image = lastFrame.image
+        }
+    }
+    
+    /// Detaches the given view from this controller.
+    /// If no views attached views remain, the last strong reference to this controller is nilled out
+    /// and image animation will stop at the next CGAnimateImageDataWithBlock callback.
+    func detach(from view: GIFImageView) {
+        // todo: does === work the way i want here
+        imageViews.removeAll(where: { $0 === view })
+        view.gifController = nil
+    }
+    
+    func startAnimating() {
+        guard state.shouldStop else { return }
+        
+        state = .playing
+        
+        CGAnimateImageDataWithBlock(gifData as CFData, nil) { [weak self] (frameIndex, cgImage, stop) in
+            guard let self = self else {
+                stop.pointee = true
+                return
+            }
+            let image = UIImage(cgImage: cgImage)
+            self.lastFrame = (image, frameIndex)
+            for case let .some(view) in self.imageViews {
+                view.image = image
+            }
+            stop.pointee = self.state.shouldStop
+        }
+    }
+    
+    func stopAnimating() {
+        guard state == .playing else { return }
+        
+        state = .stopping
+    }
+    
+    enum State: Equatable {
+        case stopped, playing, stopping
+        
+        var shouldStop: Bool {
+            self == .stopped || self == .stopping
+        }
+    }
+    
+}