Tusker/Screens/Large Image/LargeImageViewController.swift

@@ -17,16 +17,17 @@ class LargeImageViewController: UIViewController, UIScrollViewDelegate, LargeIma
     
     @IBOutlet weak var scrollView: UIScrollView!
     @IBOutlet weak var topControlsView: UIView!
+    @IBOutlet weak var topControlsHeightConstraint: NSLayoutConstraint!
+    @IBOutlet weak var shareButton: UIButton!
+    @IBOutlet weak var shareButtonTopConstraint: NSLayoutConstraint!
+    @IBOutlet weak var shareButtonLeadingConstraint: NSLayoutConstraint!
+    @IBOutlet weak var closeButton: UIButton!
+    @IBOutlet weak var closeButtonTopConstraint: NSLayoutConstraint!
+    @IBOutlet weak var closeButtonTrailingConstraint: NSLayoutConstraint!
+    
     @IBOutlet weak var bottomControlsView: UIView!
     @IBOutlet weak var descriptionLabel: UILabel!
     
-    private var shareContainer: UIView!
-    private var shareImage: UIImageView!
-    private var shareButtonTopConstraint: NSLayoutConstraint!
-    private var shareButtonLeadingConstraint: NSLayoutConstraint!
-    private var closeButtonTopConstraint: NSLayoutConstraint!
-    private var closeButtonTrailingConstraint: NSLayoutConstraint!
-
     var contentView: LargeImageContentView {
         didSet {
             oldValue.removeFromSuperview()
@@ -85,13 +86,9 @@ class LargeImageViewController: UIViewController, UIScrollViewDelegate, LargeIma
         super.viewDidLoad()
 
         setupContentView()
-        setupControls()
 
         setControlsVisible(initialControlsVisible, animated: false)
-        if contentView.activityItemsForSharing.isEmpty {
-            shareContainer.isUserInteractionEnabled = false
-            shareImage.tintColor = .systemGray
-        }
+        shareButton.isEnabled = !contentView.activityItemsForSharing.isEmpty
 
         scrollView.delegate = self
 
@@ -129,62 +126,6 @@ class LargeImageViewController: UIViewController, UIScrollViewDelegate, LargeIma
         ])
     }
 
-    private func setupControls() {
-        shareContainer = UIView()
-        shareContainer.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(sharePressed)))
-        shareContainer.translatesAutoresizingMaskIntoConstraints = false
-        topControlsView.addSubview(shareContainer)
-        shareImage = UIImageView(image: UIImage(systemName: "square.and.arrow.up"))
-        shareImage.tintColor = .white
-        shareImage.contentMode = .scaleAspectFit
-        shareImage.translatesAutoresizingMaskIntoConstraints = false
-        shareContainer.addSubview(shareImage)
-        shareButtonTopConstraint = shareImage.topAnchor.constraint(greaterThanOrEqualTo: shareContainer.topAnchor)
-        shareButtonLeadingConstraint = shareImage.leadingAnchor.constraint(greaterThanOrEqualTo: shareContainer.leadingAnchor)
-        NSLayoutConstraint.activate([
-            shareContainer.topAnchor.constraint(equalTo: topControlsView.topAnchor),
-            shareContainer.leadingAnchor.constraint(equalTo: topControlsView.leadingAnchor),
-            shareContainer.bottomAnchor.constraint(equalTo: topControlsView.bottomAnchor),
-            shareContainer.widthAnchor.constraint(greaterThanOrEqualToConstant: 50),
-            shareContainer.heightAnchor.constraint(greaterThanOrEqualToConstant: 50),
-            
-            shareImage.centerXAnchor.constraint(equalTo: shareContainer.centerXAnchor),
-            shareImage.centerYAnchor.constraint(equalTo: shareContainer.centerYAnchor),
-            shareButtonTopConstraint,
-            shareButtonLeadingConstraint,
-            
-            shareImage.widthAnchor.constraint(equalToConstant: 24),
-            shareImage.heightAnchor.constraint(equalToConstant: 24),
-        ])
-        
-        let closeContainer = UIView()
-        closeContainer.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(closeButtonPressed)))
-        closeContainer.translatesAutoresizingMaskIntoConstraints = false
-        topControlsView.addSubview(closeContainer)
-        let closeImage = UIImageView(image: UIImage(systemName: "xmark"))
-        closeImage.tintColor = .white
-        closeImage.contentMode = .scaleAspectFit
-        closeImage.translatesAutoresizingMaskIntoConstraints = false
-        closeContainer.addSubview(closeImage)
-        closeButtonTopConstraint = closeImage.topAnchor.constraint(greaterThanOrEqualTo: closeContainer.topAnchor)
-        closeButtonTrailingConstraint = closeContainer.trailingAnchor.constraint(greaterThanOrEqualTo: closeImage.trailingAnchor)
-        NSLayoutConstraint.activate([
-            closeContainer.topAnchor.constraint(equalTo: topControlsView.topAnchor),
-            closeContainer.trailingAnchor.constraint(equalTo: topControlsView.trailingAnchor),
-            closeContainer.bottomAnchor.constraint(equalTo: closeContainer.bottomAnchor),
-            closeContainer.widthAnchor.constraint(greaterThanOrEqualToConstant: 50),
-            closeContainer.heightAnchor.constraint(greaterThanOrEqualToConstant: 50),
-            
-            closeImage.centerXAnchor.constraint(equalTo: closeContainer.centerXAnchor),
-            closeImage.centerYAnchor.constraint(equalTo: closeContainer.centerYAnchor),
-            closeButtonTopConstraint,
-            closeButtonTrailingConstraint,
-            
-            closeImage.widthAnchor.constraint(equalToConstant: 24),
-            closeImage.heightAnchor.constraint(equalToConstant: 24),
-        ])
-    }
-
     override func viewDidLayoutSubviews() {
         super.viewDidLayoutSubviews()
         
@@ -215,7 +156,7 @@ class LargeImageViewController: UIViewController, UIScrollViewDelegate, LargeIma
             // since the corner radius didn't change
             let notchWidth: CGFloat = 210
             let earWidth = (view.bounds.width - notchWidth) / 2
-            let offset = (earWidth - shareImage.bounds.width) / 2
+            let offset = (earWidth - shareButton.bounds.width) / 2
             shareButtonLeadingConstraint.constant = offset
             closeButtonTrailingConstraint.constant = offset
         } else if pillDeviceTopInsets.contains(view.safeAreaInsets.top) {
@@ -334,7 +275,7 @@ class LargeImageViewController: UIViewController, UIScrollViewDelegate, LargeIma
     
     @IBAction func sharePressed(_ sender: Any) {
         let activityVC = UIActivityViewController(activityItems: contentView.activityItemsForSharing, applicationActivities: nil)
-        activityVC.popoverPresentationController?.sourceView = shareImage
+        activityVC.popoverPresentationController?.sourceView = shareButton
         present(activityVC, animated: true)
     }
     

Tusker/Screens/Large Image/LargeImageViewController.xib

@@ -11,8 +11,15 @@
         <placeholder placeholderIdentifier="IBFilesOwner" id="-1" userLabel="File's Owner" customClass="LargeImageViewController" customModule="Tusker" customModuleProvider="target">
             <connections>
                 <outlet property="bottomControlsView" destination="rPa-Zu-T6g" id="Rgz-AQ-9nt"/>
+                <outlet property="closeButton" destination="pnA-ne-k0v" id="RPP-cB-9ap"/>
+                <outlet property="closeButtonTopConstraint" destination="ImD-2H-0XK" id="DUe-b1-a2N"/>
+                <outlet property="closeButtonTrailingConstraint" destination="JFe-ig-3Ic" id="cWO-Rr-y3F"/>
                 <outlet property="descriptionLabel" destination="eo5-fc-RV8" id="vrW-RJ-y5k"/>
                 <outlet property="scrollView" destination="Skj-xq-AgQ" id="TFb-zF-m1b"/>
+                <outlet property="shareButton" destination="vhp-0u-Q0S" id="JZS-K9-4w9"/>
+                <outlet property="shareButtonLeadingConstraint" destination="MJx-2r-p0k" id="Dn5-Eg-Pid"/>
+                <outlet property="shareButtonTopConstraint" destination="sgG-dC-xXP" id="Rjp-od-00F"/>
+                <outlet property="topControlsHeightConstraint" destination="6XT-D6-8FS" id="mTB-LF-50H"/>
                 <outlet property="topControlsView" destination="kHo-B9-R7a" id="8sJ-xQ-7ix"/>
                 <outlet property="view" destination="BJw-5C-9nT" id="1C2-VA-mNf"/>
             </connections>
@@ -26,8 +33,45 @@
                     <rect key="frame" x="0.0" y="0.0" width="375" height="667"/>
                     <gestureRecognizers/>
                 </scrollView>
-                <view contentMode="scaleToFill" ambiguous="YES" translatesAutoresizingMaskIntoConstraints="NO" id="kHo-B9-R7a">
+                <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="kHo-B9-R7a">
                     <rect key="frame" x="0.0" y="0.0" width="375" height="36"/>
+                    <subviews>
+                        <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" lineBreakMode="middleTruncation" pointerInteraction="YES" translatesAutoresizingMaskIntoConstraints="NO" id="vhp-0u-Q0S">
+                            <rect key="frame" x="16" y="16" width="20" height="20"/>
+                            <constraints>
+                                <constraint firstAttribute="height" constant="20" id="4tF-oL-qXT"/>
+                                <constraint firstAttribute="width" constant="20" id="zWx-jJ-dBj"/>
+                            </constraints>
+                            <fontDescription key="fontDescription" style="UICTFontTextStyleBody"/>
+                            <color key="tintColor" white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
+                            <state key="normal" image="square.and.arrow.up" catalog="system"/>
+                            <connections>
+                                <action selector="sharePressed:" destination="-1" eventType="touchUpInside" id="7Oz-zv-m2t"/>
+                            </connections>
+                        </button>
+                        <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" lineBreakMode="middleTruncation" pointerInteraction="YES" translatesAutoresizingMaskIntoConstraints="NO" id="pnA-ne-k0v">
+                            <rect key="frame" x="339" y="16" width="20" height="20"/>
+                            <constraints>
+                                <constraint firstAttribute="width" constant="20" id="eg0-hN-rda"/>
+                                <constraint firstAttribute="height" constant="20" id="fmA-pI-8WB"/>
+                            </constraints>
+                            <fontDescription key="fontDescription" style="UICTFontTextStyleBody"/>
+                            <color key="tintColor" white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
+                            <state key="normal" image="xmark" catalog="system"/>
+                            <connections>
+                                <action selector="closeButtonPressed:" destination="-1" eventType="touchUpInside" id="7o3-ET-EMo"/>
+                            </connections>
+                        </button>
+                    </subviews>
+                    <constraints>
+                        <constraint firstAttribute="height" secondItem="pnA-ne-k0v" secondAttribute="height" constant="16" id="6XT-D6-8FS"/>
+                        <constraint firstItem="pnA-ne-k0v" firstAttribute="top" secondItem="kHo-B9-R7a" secondAttribute="top" constant="16" id="ImD-2H-0XK"/>
+                        <constraint firstAttribute="trailing" secondItem="pnA-ne-k0v" secondAttribute="trailing" constant="16" id="JFe-ig-3Ic"/>
+                        <constraint firstItem="vhp-0u-Q0S" firstAttribute="leading" secondItem="kHo-B9-R7a" secondAttribute="leading" constant="16" id="MJx-2r-p0k"/>
+                        <constraint firstAttribute="bottom" secondItem="vhp-0u-Q0S" secondAttribute="bottom" id="fi6-JS-UmZ"/>
+                        <constraint firstAttribute="bottom" secondItem="pnA-ne-k0v" secondAttribute="bottom" id="hEU-VY-WTd"/>
+                        <constraint firstItem="vhp-0u-Q0S" firstAttribute="top" secondItem="kHo-B9-R7a" secondAttribute="top" constant="16" id="sgG-dC-xXP"/>
+                    </constraints>
                 </view>
                 <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="rPa-Zu-T6g">
                     <rect key="frame" x="0.0" y="622.5" width="375" height="44.5"/>
@@ -66,4 +110,8 @@
             <point key="canvasLocation" x="-164" y="476"/>
         </view>
     </objects>
+    <resources>
+        <image name="square.and.arrow.up" catalog="system" width="115" height="128"/>
+        <image name="xmark" catalog="system" width="128" height="113"/>
+    </resources>
 </document>

Tusker/Screens/Timeline/TimelineViewController.swift

@@ -246,9 +246,17 @@ class TimelineViewController: UIViewController, TimelineLikeCollectionViewContro
             snapshot.insertItems(presentItems.map { .status(id: $0, state: .unknown) }, beforeItem: .gap)
             
             if applySnapshotBeforeScrolling {
-                let firstVisibleIndexPath = collectionView.indexPathsForVisibleItems.min()!
-                let firstVisibleItem = dataSource.itemIdentifier(for: firstVisibleIndexPath)!
-                applySnapshot(snapshot, maintainingBottomRelativeScrollPositionOf: firstVisibleItem)
+                // use a snapshot of the collection view to hide the flicker as the content offset changes and then changes back
+                let snapshotView = collectionView.snapshotView(afterScreenUpdates: false)!
+                snapshotView.layer.zPosition = 1000
+                snapshotView.frame = view.bounds
+                view.addSubview(snapshotView)
+                
+                let bottomOffset = collectionView.contentSize.height - collectionView.contentOffset.y
+                self.dataSource.apply(snapshot, animatingDifferences: false) {
+                    self.collectionView.contentOffset = CGPoint(x: 0, y: self.collectionView.contentSize.height - bottomOffset)
+                    snapshotView.removeFromSuperview()
+                }
             }
             
             var config = ToastConfiguration(title: "Jump to present")
@@ -268,50 +276,6 @@ class TimelineViewController: UIViewController, TimelineLikeCollectionViewContro
         }
     }
     
-    // NOTE: this only works when items are being inserted ABOVE the item to maintain
-    private func applySnapshot(_ snapshot: NSDiffableDataSourceSnapshot<Section, Item>, maintainingBottomRelativeScrollPositionOf itemToMaintain: Item) {
-        // use a snapshot of the collection view to hide the flicker as the content offset changes and then changes back
-        let snapshotView = collectionView.snapshotView(afterScreenUpdates: false)!
-        snapshotView.layer.zPosition = 1000
-        snapshotView.frame = view.bounds
-        view.addSubview(snapshotView)
-        
-        var firstItemAfterOriginalGapOffsetFromTop: CGFloat = 0
-        if let indexPath = dataSource.indexPath(for: itemToMaintain),
-           let cell = collectionView.cellForItem(at: indexPath) {
-            // subtract top safe area inset b/c scrollToItem at .top aligns the top of the cell to the top of the safe area
-            firstItemAfterOriginalGapOffsetFromTop = cell.convert(.zero, to: view).y - view.safeAreaInsets.top
-        }
-        
-        dataSource.apply(snapshot, animatingDifferences: false) {
-            if let indexPathOfItemAfterOriginalGap = self.dataSource.indexPath(for: itemToMaintain) {
-                // scroll up until we've accumulated enough MEASURED height that we can put the
-                // firstItemAfterOriginalGapCell at the top of the screen and then scroll down by
-                // firstItemAfterOriginalGapOffsetFromTop without intruding into unmeasured area
-                var cur = indexPathOfItemAfterOriginalGap
-                var amountScrolledUp: CGFloat = 0
-                while true {
-                    if cur.row <= 0 {
-                        break
-                    }
-                    if let cell = self.collectionView.cellForItem(at: indexPathOfItemAfterOriginalGap),
-                       cell.convert(.zero, to: self.view).y - self.view.safeAreaInsets.top > firstItemAfterOriginalGapOffsetFromTop {
-                        break
-                    }
-                    cur = IndexPath(row: cur.row - 1, section: cur.section)
-                    self.collectionView.scrollToItem(at: cur, at: .top, animated: false)
-                    self.collectionView.layoutIfNeeded()
-                    let attrs = self.collectionView.layoutAttributesForItem(at: cur)!
-                    amountScrolledUp += attrs.size.height
-                }
-                self.collectionView.contentOffset.y += amountScrolledUp
-                self.collectionView.contentOffset.y -= firstItemAfterOriginalGapOffsetFromTop
-            }
-            
-            snapshotView.removeFromSuperview()
-        }
-    }
-    
 }
 
 extension TimelineViewController {
@@ -575,8 +539,29 @@ extension TimelineViewController {
             }
             
             if addedItems {
-                let firstItemAfterOriginalGap = statusItems[gapIndex + 1]
-                applySnapshot(snapshot, maintainingBottomRelativeScrollPositionOf: firstItemAfterOriginalGap)
+                // use a snapshot of the collection view to hide the flicker as the content offset changes and then changes back
+                let snapshotView = collectionView.snapshotView(afterScreenUpdates: false)!
+                snapshotView.layer.zPosition = 1000
+                snapshotView.frame = view.bounds
+                view.addSubview(snapshotView)
+                
+                // Yes, these are all load bearing. Setting the contentOffset seems to cause the collection view to recalculate the size
+                // of some cells, thus changing the contentSize and the offset necessary to match to match the bottom offset.
+                // Three DispatchQueue.main.async's seems to be the fewest we can reliably get away with.
+                let bottomOffset = collectionView.contentSize.height - collectionView.contentOffset.y
+                dataSource.apply(snapshot, animatingDifferences: false) {
+                    self.collectionView.contentOffset = CGPoint(x: 0, y: self.collectionView.contentSize.height - bottomOffset)
+                    DispatchQueue.main.async {
+                        self.collectionView.contentOffset = CGPoint(x: 0, y: self.collectionView.contentSize.height - bottomOffset)
+                        DispatchQueue.main.async {
+                            self.collectionView.contentOffset = CGPoint(x: 0, y: self.collectionView.contentSize.height - bottomOffset)
+                            DispatchQueue.main.async {
+                                self.collectionView.contentOffset = CGPoint(x: 0, y: self.collectionView.contentSize.height - bottomOffset)
+                                snapshotView.removeFromSuperview()
+                            }
+                        }
+                    }
+                }
             } else {
                 dataSource.apply(snapshot, animatingDifferences: true) {}
             }