Fix multi-attachment layout issues

Tusker/Screens/Attachment/AttachmentViewController.swift

@@ -62,7 +62,7 @@ class AttachmentViewController: UIViewController {
     
     func createLargeImage(data: Data) {
         guard let image = UIImage(data: data) else { return }
-        largeImageVC = LargeImageViewController(image: image, description: attachment.description, sourceFrame: nil, sourceCornerRadius: nil)
+        largeImageVC = LargeImageViewController(image: image, description: attachment.description, sourceInfo: nil)
         largeImageVC!.initialControlsVisible = initialControlsVisible
         largeImageVC!.shrinkGestureEnabled = false
         if attachment.url.pathExtension == "gif" {

Tusker/Screens/Gallery/GalleryViewController.swift

@@ -13,7 +13,7 @@ class GalleryViewController: UIPageViewController, UIPageViewControllerDataSourc
     var dismissInteractionController: LargeImageInteractionController?
     
     let attachments: [Attachment]
-    let sourcesInfo: [(CGRect, CGFloat)]
+    let sourcesInfo: [LargeImageViewController.SourceInfo?]
     let startIndex: Int
     
     let pages: [AttachmentViewController]
@@ -34,7 +34,7 @@ class GalleryViewController: UIPageViewController, UIPageViewControllerDataSourc
             viewControllers?.first
     }
     
-    init(attachments: [Attachment], sourcesInfo: [(CGRect, CGFloat)], startIndex: Int) {
+    init(attachments: [Attachment], sourcesInfo: [LargeImageViewController.SourceInfo?], startIndex: Int) {
         self.attachments = attachments
         self.sourcesInfo = sourcesInfo
         self.startIndex = startIndex

Tusker/Screens/Gallery/Transitions/GalleryExpandAnimationController.swift

@@ -19,10 +19,15 @@ class GalleryExpandAnimationController: NSObject, UIViewControllerAnimatedTransi
             let toVC = transitionContext.viewController(forKey: .to) as? GalleryViewController else {
                 return
         }
-        let attachment = toVC.attachments[toVC.startIndex]
-        let (sourceFrame, sourceCornerRadius) = toVC.sourcesInfo[toVC.startIndex]
         
         let finalVCFrame = transitionContext.finalFrame(for: toVC)
+        guard let (sourceFrame, sourceCornerRadius) = toVC.sourcesInfo[toVC.startIndex] else {
+            toVC.view.frame = finalVCFrame
+            transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
+            return
+        }
+        
+        let attachment = toVC.attachments[toVC.startIndex]
 
         guard let data = ImageCache.attachments.get(attachment.url), let image = UIImage(data: data) else {
             toVC.view.frame = finalVCFrame

Tusker/Screens/Gallery/Transitions/GalleryShrinkAnimationController.swift

@@ -26,7 +26,10 @@ class GalleryShrinkAnimationController: NSObject, UIViewControllerAnimatedTransi
                 return
         }
         
-        let (sourceFrame, sourceCornerRadius) = fromVC.sourcesInfo[fromVC.currentIndex]
+        guard let (sourceFrame, sourceCornerRadius) = fromVC.sourcesInfo[fromVC.currentIndex] else {
+            transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
+            return
+        }
         let originalVCFrame = fromVC.view.frame
         
         let attachment = fromVC.attachments[fromVC.currentIndex]

Tusker/Screens/Large Image/LargeImageViewController.swift

@@ -13,8 +13,9 @@ import Gifu
 
 class LargeImageViewController: UIViewController, UIScrollViewDelegate {
 
-    var originFrame: CGRect?
+    typealias SourceInfo = (frame: CGRect, cornerRadius: CGFloat)
-    var originCornerRadius: CGFloat?
+    
+    var sourceInfo: SourceInfo?
     var dismissInteractionController: LargeImageInteractionController?
     
     @IBOutlet weak var scrollView: UIScrollView!
@@ -60,11 +61,10 @@ class LargeImageViewController: UIViewController, UIScrollViewDelegate {
         return !controlsVisible
     }
     
-    init(image: UIImage, description: String?, sourceFrame: CGRect?, sourceCornerRadius: CGFloat?) {
+    init(image: UIImage, description: String?, sourceInfo: SourceInfo?) {
         self.image = image
         self.imageDescription = description
-        self.originFrame = sourceFrame
+        self.sourceInfo = sourceInfo
-        self.originCornerRadius = sourceCornerRadius
 
         super.init(nibName: "LargeImageViewController", bundle: nil)
         

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

@@ -17,13 +17,18 @@ class LargeImageExpandAnimationController: NSObject, UIViewControllerAnimatedTra
     
     func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
         guard let fromVC = transitionContext.viewController(forKey: .from),
-            let toVC = transitionContext.viewController(forKey: .to) as? LargeImageViewController,
+            let toVC = transitionContext.viewController(forKey: .to) as? LargeImageViewController else {
-            let originFrame = toVC.originFrame else {
                 return
         }
         
-        let containerView = transitionContext.containerView
         let finalVCFrame = transitionContext.finalFrame(for: toVC)
+        guard let (originFrame, originCornerRadius) = toVC.sourceInfo else {
+            toVC.view.frame = finalVCFrame
+            transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
+            return
+        }
+        
+        let containerView = transitionContext.containerView
         let image = toVC.imageView.image!
         let ratio = image.size.width / image.size.height
         let width = finalVCFrame.width
@@ -36,7 +41,7 @@ class LargeImageExpandAnimationController: NSObject, UIViewControllerAnimatedTra
             imageView.animate(withGIFData: gifData)
         }
         imageView.contentMode = .scaleAspectFill
-        imageView.layer.cornerRadius = toVC.originCornerRadius!
+        imageView.layer.cornerRadius = originCornerRadius
         imageView.layer.masksToBounds = true
         
         let blackView = UIView(frame: finalVCFrame)

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

@@ -23,11 +23,15 @@ class LargeImageShrinkAnimationController: NSObject, UIViewControllerAnimatedTra
     
     func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
         guard let fromVC = transitionContext.viewController(forKey: .from) as? LargeImageViewController,
-            let toVC = transitionContext.viewController(forKey: .to),
+            let toVC = transitionContext.viewController(forKey: .to) else {
-            let finalFrame = fromVC.originFrame else {
                 return
         }
         
+        guard let (finalFrame, finalCornerRadius) = fromVC.sourceInfo else {
+            transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
+            return
+        }
+        
         let originalVCFrame = fromVC.view.frame
         
         let containerView = transitionContext.containerView
@@ -57,7 +61,7 @@ class LargeImageShrinkAnimationController: NSObject, UIViewControllerAnimatedTra
         let duration = transitionDuration(using: transitionContext)
         UIView.animate(withDuration: duration, animations: {
             imageView.frame = finalFrame
-            imageView.layer.cornerRadius = fromVC.originCornerRadius!
+            imageView.layer.cornerRadius = finalCornerRadius
             blackView.alpha = 0
         }, completion: { _ in
             blackView.removeFromSuperview()

Tusker/TuskerNavigationDelegate.swift

@@ -34,9 +34,9 @@ protocol TuskerNavigationDelegate {
     
     func showLargeImage(gifData: Data, description: String?, animatingFrom sourceView: UIView)
     
-    func gallery(attachments: [Attachment], sourceViews: [UIView], startIndex: Int) -> GalleryViewController
+    func gallery(attachments: [Attachment], sourceViews: [UIView?], startIndex: Int) -> GalleryViewController
     
-    func showGallery(attachments: [Attachment], sourceViews: [UIView], startIndex: Int)
+    func showGallery(attachments: [Attachment], sourceViews: [UIView?], startIndex: Int)
     
     func showMoreOptions(forStatus statusID: String)
     
@@ -99,7 +99,9 @@ extension TuskerNavigationDelegate where Self: UIViewController {
         present(vc, animated: true)
     }
     
-    private func sourceViewInfo(_ sourceView: UIView) -> (CGRect, CGFloat) {
+    private func sourceViewInfo(_ sourceView: UIView?) -> 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
@@ -109,19 +111,17 @@ extension TuskerNavigationDelegate where Self: UIViewController {
             let y = sourceFrame.minY * scale - scrollView.contentOffset.y + scrollView.frame.minY
             sourceFrame = CGRect(x: x, y: y, width: width, height: height)
         }
-        return (sourceFrame, sourceView.layer.cornerRadius)
+        return (frame: sourceFrame, cornerRadius: sourceView.layer.cornerRadius)
     }
     
     func largeImage(_ image: UIImage, description: String?, sourceView: UIView) -> LargeImageViewController {
-        let (sourceFrame, sourceCornerRadius) = sourceViewInfo(sourceView)
+        let vc = LargeImageViewController(image: image, description: description, sourceInfo: sourceViewInfo(sourceView))
-        let vc = LargeImageViewController(image: image, description: description, sourceFrame: sourceFrame, sourceCornerRadius: sourceCornerRadius)
         vc.transitioningDelegate = self
         return vc
     }
     
     func largeImage(gifData: Data, description: String?, sourceView: UIView) -> LargeImageViewController {
-        let (sourceFrame, sourceCornerRadius) = sourceViewInfo(sourceView)
+        let vc = LargeImageViewController(image: UIImage(data: gifData)!, description: description, sourceInfo: sourceViewInfo(sourceView))
-        let vc = LargeImageViewController(image: UIImage(data: gifData)!, description: description, sourceFrame: sourceFrame, sourceCornerRadius: sourceCornerRadius)
         vc.transitioningDelegate = self
         vc.gifData = gifData
         return vc
@@ -135,14 +135,14 @@ extension TuskerNavigationDelegate where Self: UIViewController {
         present(largeImage(gifData: gifData, description: description, sourceView: sourceView), animated: true)
     }
     
-    func gallery(attachments: [Attachment], sourceViews: [UIView], startIndex: Int) -> GalleryViewController {
+    func gallery(attachments: [Attachment], sourceViews: [UIView?], startIndex: Int) -> GalleryViewController {
         let sourcesInfo = sourceViews.map(sourceViewInfo)
         let vc = GalleryViewController(attachments: attachments, sourcesInfo: sourcesInfo, startIndex: startIndex)
         vc.transitioningDelegate = self
         return vc
     }
     
-    func showGallery(attachments: [Attachment], sourceViews: [UIView], startIndex: Int) {
+    func showGallery(attachments: [Attachment], sourceViews: [UIView?], startIndex: Int) {
         present(gallery(attachments: attachments, sourceViews: sourceViews, startIndex: startIndex), animated: true)
     }
     

Tusker/Views/Attachments/AttachmentsContainerView.swift

@@ -13,60 +13,79 @@ class AttachmentsContainerView: UIView {
 
     var delegate: AttachmentViewDelegate?
     
+    let attachmentViews: NSHashTable<AttachmentView> = .weakObjects()
+    
     override func awakeFromNib() {
         super.awakeFromNib()
         
         self.isUserInteractionEnabled = true
     }
     
+    func getAttachmentView(for attachment: Attachment) -> AttachmentView? {
+        return attachmentViews.allObjects.first { $0.attachment.id == attachment.id }
+    }
+    
+    // MARK: - User Interaface
+    
     func updateUI(status: Status) {
         let attachments = status.attachments.filter { $0.kind == .image }
         
+        attachmentViews.removeAllObjects()
+        subviews.forEach { $0.removeFromSuperview() }
+
         if attachments.count > 0 {
             self.isHidden = false
             
-            let mainView: UIView
             switch attachments.count {
             case 1:
-                mainView = createAttachmentView(attachments[0])
+                makeMainView(createAttachmentView(attachments[0]))
             case 2:
-                mainView = createAttachmentsStack(axis: .horizontal, arrangedSubviews: [
+                let left = createAttachmentView(attachments[0])
-                    createAttachmentView(attachments[0]),
+                makeMainView(createAttachmentsStack(axis: .horizontal, arrangedSubviews: [
+                    left,
                     createAttachmentView(attachments[1])
+                ]))
+                NSLayoutConstraint.activate([
+                    left.halfWidth()
                 ])
             case 3:
-                mainView = createAttachmentsStack(axis: .horizontal, arrangedSubviews: [
+                let left = createAttachmentView(attachments[0])
-                    createAttachmentView(attachments[0]),
+                let topRight = createAttachmentView(attachments[1])
+                makeMainView(createAttachmentsStack(axis: .horizontal, arrangedSubviews: [
+                    left,
                     createAttachmentsStack(axis: .vertical, arrangedSubviews: [
-                        createAttachmentView(attachments[1]),
+                        topRight,
                         createAttachmentView(attachments[2])
                     ])
+                ]))
+                NSLayoutConstraint.activate([
+                    left.halfWidth(),
+                    topRight.halfHeight(),
                 ])
             case 4:
-                mainView = createAttachmentsStack(axis: .horizontal, arrangedSubviews: [
+                let topLeft = createAttachmentView(attachments[0])
+                let left = createAttachmentsStack(axis: .vertical, arrangedSubviews: [
+                    topLeft,
+                    createAttachmentView(attachments[2])
+                ])
+                let topRight = createAttachmentView(attachments[1])
+                makeMainView(createAttachmentsStack(axis: .horizontal, arrangedSubviews: [
+                    left,
                     createAttachmentsStack(axis: .vertical, arrangedSubviews: [
-                        createAttachmentView(attachments[0]),
+                        topRight,
-                        createAttachmentView(attachments[2])
-                    ]),
-                    createAttachmentsStack(axis: .vertical, arrangedSubviews: [
-                        createAttachmentView(attachments[1]),
                         createAttachmentView(attachments[3])
                     ])
+                ]))
+                NSLayoutConstraint.activate([
+                    left.halfWidth(),
+                    topLeft.halfHeight(),
+                    topRight.halfHeight(),
                 ])
             default:
                 fatalError("Too many attachments")
             }
-            
-            addSubview(mainView)
-            NSLayoutConstraint.activate([
-                mainView.leadingAnchor.constraint(equalTo: leadingAnchor),
-                mainView.trailingAnchor.constraint(equalTo: trailingAnchor),
-                mainView.topAnchor.constraint(equalTo: topAnchor),
-                mainView.bottomAnchor.constraint(equalTo: bottomAnchor)
-            ])
         } else {
             self.isHidden = true
-            subviews.forEach { $0.removeFromSuperview() }
         }
     }
     
@@ -74,15 +93,49 @@ class AttachmentsContainerView: UIView {
         let attachmentView = AttachmentView(attachment: attachment)
         attachmentView.delegate = delegate
         attachmentView.translatesAutoresizingMaskIntoConstraints = false
+        attachmentViews.add(attachmentView)
         return attachmentView
     }
     
     private func createAttachmentsStack(axis: NSLayoutConstraint.Axis, arrangedSubviews: [UIView]) -> UIStackView {
         let stack = UIStackView(arrangedSubviews: arrangedSubviews)
         stack.axis = axis
-        stack.spacing = 8
+        stack.spacing = 4
         stack.translatesAutoresizingMaskIntoConstraints = false
         return stack
     }
     
+    private func makeMainView(_ view: UIView) {
+        addSubview(view)
+        NSLayoutConstraint.activate([
+            view.leadingAnchor.constraint(equalTo: leadingAnchor),
+            view.trailingAnchor.constraint(equalTo: trailingAnchor),
+            view.topAnchor.constraint(equalTo: topAnchor),
+            view.bottomAnchor.constraint(equalTo: bottomAnchor)
+        ])
+    }
+    
+}
+
+fileprivate extension UIView {
+    enum RelativeSize {
+        case full, half
+        
+        var multiplier: CGFloat {
+            switch self {
+            case .full:
+                return 1
+            case .half:
+                return 0.5
+            }
+        }
+    }
+    
+    func halfWidth(spacing: CGFloat = 4) -> NSLayoutConstraint {
+        return widthAnchor.constraint(equalTo: superview!.widthAnchor, multiplier: 0.5, constant: -spacing / 2)
+    }
+    
+    func halfHeight(spacing: CGFloat = 4) -> NSLayoutConstraint {
+        return heightAnchor.constraint(equalTo: superview!.heightAnchor, multiplier: 0.5, constant: -spacing / 2)
+    }
 }

Tusker/Views/Status/StatusTableViewCell.swift

@@ -307,9 +307,7 @@ extension StatusTableViewCell: AttachmentViewDelegate {
     func showLargeAttachment(for attachmentView: AttachmentView) {
         guard let status = MastodonCache.status(for: statusID) else { fatalError("Missing cached status \(statusID!)") }
         let startIndex = status.attachments.firstIndex { $0.id == attachmentView.attachment.id } ?? 0
-        let sourceViews = status.attachments.map { attachment in
+        let sourceViews = status.attachments.map(attachmentsView.getAttachmentView(for:))
-            attachmentsView.subviews.first { ($0 as! AttachmentView).attachment.id == attachment.id }!
-        }
         delegate?.showGallery(attachments: status.attachments, sourceViews: sourceViews, startIndex: startIndex)
     }
 }