More link context menu preview tweaks

Tusker/Extensions/UIBezierPath+Helpers.swift

@@ -16,6 +16,12 @@ extension UIBezierPath {
     /// and draws a line around the outer borders of the combined shape.
     convenience init(wrappingAround rects: [CGRect]) {
         precondition(rects.count > 0)
+        
+        if rects.count == 1 {
+            self.init(rect: rects.first!)
+            return
+        }
+        
         let rects = rects.sorted { $0.minY < $1.minY }
         
         self.init()

Tusker/Views/ContentTextView.swift

@@ -22,6 +22,11 @@ class ContentTextView: LinkTextView {
     var defaultFont: UIFont = .systemFont(ofSize: 17)
     var defaultColor: UIColor = .label
     
+    // The link range currently being previewed
+    private var currentPreviewedLinkRange: NSRange?
+    // The preview created in the previewForHighlighting method, so that we can use the same one in previewForDismissing.
+    private weak var currentTargetedPreview: UITargetedPreview?
+    
     override func awakeFromNib() {
         super.awakeFromNib()
         
@@ -256,11 +261,8 @@ extension ContentTextView: MenuPreviewProvider {
 extension ContentTextView: UIContextMenuInteractionDelegate {
     func contextMenuInteraction(_ interaction: UIContextMenuInteraction, configurationForMenuAtLocation location: CGPoint) -> UIContextMenuConfiguration? {
         if let (link, range) = getLinkAtPoint(location) {
-            // Determine the line rects that the link takes up in the coordinate space of this view
+            // Store the previewed link range for use in the previewForHighlighting method
-            var rects = [CGRect]()
+            currentPreviewedLinkRange = range
-            layoutManager.enumerateEnclosingRects(forGlyphRange: range, withinSelectedGlyphRange: NSRange(location: NSNotFound, length: 0), in: textContainer) { (rect, stop) in
-                rects.append(rect)
-            }
             
             let preview: UIContextMenuContentPreviewProvider = {
                 self.getViewController(forLink: link, inRange: range)
@@ -278,66 +280,53 @@ extension ContentTextView: UIContextMenuInteractionDelegate {
                 return UIMenu(title: "", image: nil, identifier: nil, options: [], children: actions)
             }
             
-            // Use a custom UIContentMenuConfiguration subclass to pass the text line rect information
+            return UIContextMenuConfiguration(identifier: nil, previewProvider: preview, actionProvider: actions)
-            // to the `contextMenuInteraction(_:previewForHighlightingMenuWithConfiguration:)` method.
-            let configuration = ContextMenuConfiguration(identifier: nil, previewProvider: preview, actionProvider: actions)
-            configuration.textLineRects = rects
-            return configuration
         } else {
+            currentPreviewedLinkRange = nil
             return nil
         }
     }
     
     func contextMenuInteraction(_ interaction: UIContextMenuInteraction, previewForHighlightingMenuWithConfiguration configuration: UIContextMenuConfiguration) -> UITargetedPreview? {
-        // If there isn't custom text line rect data, use the default system-generated preview.
+        // If there isn't a link range, use the default system-generated preview.
-        guard let config = configuration as? ContextMenuConfiguration,
+        guard let range = currentPreviewedLinkRange else {
-              let rects = config.textLineRects,
+            return nil
-              rects.count > 0 else {
+        }
+        currentPreviewedLinkRange = nil
+        
+        // Determine the line rects that the link takes up in the coordinate space of this view.
+        var rects = [CGRect]()
+        layoutManager.enumerateEnclosingRects(forGlyphRange: range, withinSelectedGlyphRange: NSRange(location: NSNotFound, length: 0), in: textContainer) { (rect, stop) in
+            rects.append(rect)
+        }
+        
+        // Try to create a snapshot view of this view to disply as the preview.
+        // If a snapshot view cannot be created, we bail and use the system-provided preview.
+        guard let snapshot = self.snapshotView(afterScreenUpdates: false) else {
             return nil
         }
         
+        // Mask the snapshot layer to only show the text of the link, and nothing else.
+        // By default, the system-applied mask is too wide and other content may seep in.
+        let path = UIBezierPath(wrappingAround: rects)
+        let maskLayer = CAShapeLayer()
+        maskLayer.path = path.cgPath
+        snapshot.layer.mask = maskLayer
+        
+        // The preview parameters describe how the preview view is shown inside the preview.
+        let parameters = UIPreviewParameters(textLineRects: rects as [NSValue])
+        
         // Calculate the smallest rect enclosing all of the text line rects, in the coordinate space of this view.
-        var minX: CGFloat = .greatestFiniteMagnitude, maxX: CGFloat = .leastNonzeroMagnitude, minY: CGFloat = .greatestFiniteMagnitude, maxY: CGFloat = .leastNonzeroMagnitude
+        var minX: CGFloat = .greatestFiniteMagnitude, maxX: CGFloat = -.greatestFiniteMagnitude, minY: CGFloat = .greatestFiniteMagnitude, maxY: CGFloat = -.greatestFiniteMagnitude
         for rect in rects {
             minX = min(rect.minX, minX)
             maxX = max(rect.maxX, maxX)
             minY = min(rect.minY, minY)
             maxY = max(rect.maxY, maxY)
         }
-        let rectEnclosingTextLineRects = CGRect(x: minX, y: minY, width: maxX - minX, height: maxY - minY)
-        
-        // Try to create a snapshot view of this view that only shows the minimum
-        // rectangle necessary to fully display the link text (reduces the likelihood that
-        // other text will be displayed alongside it).
-        // If a snapshot view cannot be created, we bail and use the system-provided preview.
-        guard let snapshot = self.resizableSnapshotView(from: rectEnclosingTextLineRects, afterScreenUpdates: false, withCapInsets: .zero) else {
-            return nil
-        }
-        
-        // Convert the textLineRects from the context menu configuration to be in the
-        // coordinate space of the snapshot view. The snapshot view is created from
-        // rectEnclosingTextLineRects, which means that, while its size is the same as the
-        // enclosing rect, its coordinate space is relative to this text views by rectEnclosingTextLineRects.origin.
-        // Since the text line rects passed to UIPreviewParameters need to be in the coordinate space of
-        // the preview view, we subtract the origin position from each rect to convert to the snapshot view's
-        // coordinate space.
-        let rectsInCoordinateSpaceOfEnclosingRect = rects.map {
-            $0.offsetBy(dx: -rectEnclosingTextLineRects.minX, dy: -rectEnclosingTextLineRects.minY)
-        }
-        
-        // The preview parameters describe how the preview view is shown inside the prev.
-        let parameters = UIPreviewParameters(textLineRects: rectsInCoordinateSpaceOfEnclosingRect as [NSValue])
-        
-        // Mask the snapshot layer to only show the text of the link, and nothing else.
-        // By default, the system-applied mask is too wide and other content may seep in.
-        let path = UIBezierPath(wrappingAround: rectsInCoordinateSpaceOfEnclosingRect)
-        let maskLayer = CAShapeLayer()
-        maskLayer.path = path.cgPath
-        snapshot.layer.mask = maskLayer
-        
         // The center point of the the minimum enclosing rect in our coordinate space is the point where the
         // center of the preview should be, since that's also in this view's coordinate space.
-        let rectsCenter = CGPoint(x: rectEnclosingTextLineRects.midX, y: rectEnclosingTextLineRects.midY)
+        let rectsCenter = CGPoint(x: (minX + maxX) / 2, y: (minY + maxY) / 2)
         
         // The preview target describes how the preview is positioned.
         let target = UIPreviewTarget(container: self, center: rectsCenter)
@@ -347,7 +336,14 @@ extension ContentTextView: UIContextMenuInteractionDelegate {
         let snapshotContainer = UIView(frame: snapshot.bounds)
         snapshotContainer.addSubview(snapshot)
         
-        return UITargetedPreview(view: snapshotContainer, parameters: parameters, target: target)
+        let preview = UITargetedPreview(view: snapshotContainer, parameters: parameters, target: target)
+        currentTargetedPreview = preview
+        return preview
+    }
+    
+    func contextMenuInteraction(_ interaction: UIContextMenuInteraction, previewForDismissingMenuWithConfiguration configuration: UIContextMenuConfiguration) -> UITargetedPreview? {
+        // Use the same preview for dismissing as was used for highlighting, so that the link animates back to the original position.
+        return currentTargetedPreview
     }
     
     func contextMenuInteraction(_ interaction: UIContextMenuInteraction, willPerformPreviewActionForMenuWith configuration: UIContextMenuConfiguration, animator: UIContextMenuInteractionCommitAnimating) {
@@ -358,10 +354,4 @@ extension ContentTextView: UIContextMenuInteractionDelegate {
             }
         }
     }
-    
-    /// Used to pass text line rect data between `contextMenuInteraction(_:configurationForMenuAtLocation:)` and `contextMenuInteraction(_:previewForHighlightingMenuWithConfiguration:)`
-    fileprivate class ContextMenuConfiguration: UIContextMenuConfiguration {
-        /// The line rects of the source of this context menu configuration in the coordinate space of the preview target view.
-        var textLineRects: [CGRect]?
-    }
 }