perf: use calayer instead of nsview for lightimageview

alt-tab-macos.xcodeproj/project.pbxproj

@@ -154,6 +154,7 @@
 		BF0C8973EC078169170F2634 /* CliEvents.swift in Sources */ = {isa = PBXBuildFile; fileRef = BF0C8C69316EAAF6DC9AE391 /* CliEvents.swift */; };
 		BF0C898511686611E4D7D81E /* Button.swift in Sources */ = {isa = PBXBuildFile; fileRef = BF0C8B2C057099EDABE46779 /* Button.swift */; };
 		BF0C8991399A3277A9A02FFA /* LightImageView.swift in Sources */ = {isa = PBXBuildFile; fileRef = BF0C8E63BE7394A6591E74E0 /* LightImageView.swift */; };
+		BF0C8992399A3277A9A02FFB /* LightImageLayer.swift in Sources */ = {isa = PBXBuildFile; fileRef = BF0C8E64BE7394A6591E74E1 /* LightImageLayer.swift */; };
 		BF0C89B4B17D7843C32A102E /* Markdown.swift in Sources */ = {isa = PBXBuildFile; fileRef = BF0C8353097840D7DB1E0E2E /* Markdown.swift */; };
 		BF0C89C49CFBAAB4646BB8CB /* InfoPlist.strings in Resources */ = {isa = PBXBuildFile; fileRef = BF0C82A8848224E76B880A83 /* InfoPlist.strings */; };
 		BF0C89F0632E0A2EC52D9168 /* InfoPlist.strings in Resources */ = {isa = PBXBuildFile; fileRef = BF0C87749F1A64E2D3305181 /* InfoPlist.strings */; };
@@ -547,6 +548,7 @@
 		BF0C8E54658B4DAEA0528200 /* menubar-2@2x.png */ = {isa = PBXFileReference; lastKnownFileType = image.png; path = "menubar-2@2x.png"; sourceTree = "<group>"; };
 		BF0C8E5D2BD5F7F93DF77DF5 /* sk */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.plist.strings; name = sk; path = InfoPlist.strings; sourceTree = "<group>"; };
 		BF0C8E63BE7394A6591E74E0 /* LightImageView.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = LightImageView.swift; sourceTree = "<group>"; };
+		BF0C8E64BE7394A6591E74E1 /* LightImageLayer.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = LightImageLayer.swift; sourceTree = "<group>"; };
 		BF0C8E7B087DCC97A454C0AE /* uk */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.plist.strings; name = uk; path = InfoPlist.strings; sourceTree = "<group>"; };
 		BF0C8E94CDFB672663333546 /* lt */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.plist.strings; name = lt; path = InfoPlist.strings; sourceTree = "<group>"; };
 		BF0C8E9D0B36A8872D5B7653 /* nb */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.plist.strings; name = nb; path = InfoPlist.strings; sourceTree = "<group>"; };
@@ -1503,6 +1505,7 @@
 				1C9617C5839903D752070CF2 /* ImageTextButtonView.swift */,
 				BF0C896FD4907CD85D62C124 /* WindowlessAppIndicator.swift */,
 				BF0C8E63BE7394A6591E74E0 /* LightImageView.swift */,
+				BF0C8E64BE7394A6591E74E1 /* LightImageLayer.swift */,
 				BF0C8DC2A355E29516DD2FAF /* CustomRecorderControlTestable.swift */,
 			);
 			path = "generic-components";
@@ -2540,6 +2543,7 @@
 				BF0C8973EC078169170F2634 /* CliEvents.swift in Sources */,
 				BF0C8521DA3078516615C414 /* HelperExtensionsTestable.swift in Sources */,
 				BF0C8991399A3277A9A02FFA /* LightImageView.swift in Sources */,
+				BF0C8992399A3277A9A02FFB /* LightImageLayer.swift in Sources */,
 				BF0C8F40C2D0FF7601D926D3 /* LightweightTimer.swift in Sources */,
 				BF0C88A9AB286CB7CDC1019E /* MainMenu.swift in Sources */,
 				BF0C826C7F8C5F68732FD75B /* DebugMenu.swift in Sources */,

src/api-wrappers/HelperExtensions.swift

@@ -89,6 +89,22 @@ extension NSColor {
     }
 }
 
+extension CALayer {
+    func centerInSuperlayer(x: Bool = false, y: Bool = false) {
+        guard let superlayer else { return }
+        if x { frame.origin.x = ((superlayer.bounds.width - frame.width) / 2).rounded() }
+        if y { frame.origin.y = ((superlayer.bounds.height - frame.height) / 2).rounded() }
+    }
+
+    func applyShadow(_ shadow: NSShadow?) {
+        guard let shadow else { shadowOpacity = 0; return }
+        shadowColor = shadow.shadowColor?.cgColor
+        shadowOffset = shadow.shadowOffset
+        shadowRadius = shadow.shadowBlurRadius
+        shadowOpacity = 1.0
+    }
+}
+
 extension NSView {
     // constrain size to fittingSize
     func fit() {

src/ui/generic-components/LightImageLayer.swift

@@ -0,0 +1,104 @@
+import Cocoa
+
+/// this is a lightweight CALayer which displays an image
+/// it is an alternative to NSView-based image display, avoiding AppKit overhead (layout recursion, responder chain, drag-and-drop)
+class LightImageLayer: CALayer {
+    private var outlineLayer: CAShapeLayer!
+    private var handRaisedLayer: CALayer!
+    private let withTransparencyChecks: Bool
+
+    init(withTransparencyChecks: Bool = false) {
+        self.withTransparencyChecks = withTransparencyChecks
+        super.init()
+        contentsGravity = .resize
+        magnificationFilter = .trilinear
+        minificationFilter = .trilinear
+        minificationFilterBias = 0.0
+        shouldRasterize = false
+        delegate = NoAnimationDelegate.shared
+        setupOutlineLayer()
+        setupHandRaisedLayer()
+    }
+
+    required init?(coder: NSCoder) {
+        fatalError("Class only supports programmatic initialization")
+    }
+
+    override init(layer: Any) {
+        let other = layer as? LightImageLayer
+        self.withTransparencyChecks = other?.withTransparencyChecks ?? false
+        super.init(layer: layer)
+    }
+
+    private func setupOutlineLayer() {
+        outlineLayer = CAShapeLayer()
+        outlineLayer.name = "outline"
+        outlineLayer.fillColor = nil
+        outlineLayer.lineWidth = 1.0
+        outlineLayer.lineDashPattern = [4, 3]
+        outlineLayer.lineCap = .round
+        outlineLayer.lineJoin = .round
+        outlineLayer.isHidden = true
+        addSublayer(outlineLayer)
+    }
+
+    private func setupHandRaisedLayer() {
+        guard #available(macOS 11.0, *) else { return }
+        handRaisedLayer = CALayer()
+        handRaisedLayer.contentsGravity = .resizeAspect
+        handRaisedLayer.isHidden = true
+        addSublayer(handRaisedLayer)
+    }
+
+    private func updateOutlineLayer(_ fullyTransparent: Bool) {
+        outlineLayer.isHidden = !fullyTransparent
+        guard fullyTransparent else { return }
+        let inset: CGFloat = 0.5
+        let radius: CGFloat = 8.0
+        outlineLayer.frame = bounds
+        let rect = bounds.insetBy(dx: inset, dy: inset)
+        let path = CGPath(roundedRect: rect, cornerWidth: radius, cornerHeight: radius, transform: nil)
+        outlineLayer.path = path
+        outlineLayer.strokeColor = Appearance.fontColor.cgColor
+    }
+
+    private func updateHandRaisedLayer(_ fullyTransparent: Bool) {
+        guard #available(macOS 11.0, *) else { return }
+        handRaisedLayer.isHidden = !fullyTransparent
+        guard fullyTransparent else { return }
+        let minSize = min(Appearance.iconSize, bounds.width * 0.9, bounds.height * 0.9)
+        let maxSize = Appearance.iconSize * 3
+        let ratio = min(bounds.width / ThumbnailView.maxThumbnailWidth(), bounds.height / ThumbnailView.maxThumbnailHeight())
+        let pointSize = max(minSize, maxSize * ratio)
+        let config = NSImage.SymbolConfiguration(pointSize: pointSize, weight: .regular)
+        guard let image = NSImage(systemSymbolName: "hand.raised.fill", accessibilityDescription: nil)?.withSymbolConfiguration(config) else { return }
+        handRaisedLayer.contents = image.tinted(Appearance.fontColor)
+        handRaisedLayer.bounds = CGRect(x: 0, y: 0, width: pointSize, height: pointSize)
+        handRaisedLayer.position = CGPoint(x: bounds.midX, y: bounds.midY)
+    }
+
+    func updateContents(_ caLayerContents: CALayerContents, _ size: NSSize) {
+        var fullyTransparent = false
+        switch caLayerContents {
+        case .cgImage(let image?):
+            contents = image
+            if withTransparencyChecks {
+                fullyTransparent = image.isFullyTransparent()
+            }
+        case .pixelBuffer(let pixelBuffer?):
+            contents = CVPixelBufferGetIOSurface(pixelBuffer)?.takeUnretainedValue()
+        default: break
+        }
+        if frame.size != size {
+            frame.size = size
+        }
+        if withTransparencyChecks {
+            updateOutlineLayer(fullyTransparent)
+            updateHandRaisedLayer(fullyTransparent)
+        }
+    }
+
+    func releaseImage() {
+        contents = nil
+    }
+}

src/ui/generic-components/LightImageView.swift

@@ -1,106 +1,35 @@
 import Cocoa
 
-/// this is a lightweight view which displays an image using its CALayer
+/// thin NSView wrapper around LightImageLayer, for use where AppKit requires an NSView (contentView, Auto Layout, NSStackView)
-/// it is an alternative to NSImageView, which doesn't have internal complexities and performance costs
 class LightImageView: NSView {
-    private var outlineLayer: CAShapeLayer!
+    let imageLayer: LightImageLayer
-    private var handRaisedLayer: CALayer!
-    private let withTransparencyChecks: Bool
 
     required init?(coder: NSCoder) {
         fatalError("Class only supports programmatic initialization")
     }
 
     init(frame frameRect: NSRect = .zero, withTransparencyChecks: Bool = false) {
-        self.withTransparencyChecks = withTransparencyChecks
+        imageLayer = LightImageLayer(withTransparencyChecks: withTransparencyChecks)
         super.init(frame: frameRect)
         wantsLayer = true
-        // configure the layer for efficient GPU-scaling
+        layer!.addSublayer(imageLayer)
-        layer!.contentsGravity = .resize
-        layer!.magnificationFilter = .trilinear
-        layer!.minificationFilter = .trilinear
-        layer!.minificationFilterBias = 0.0
-        layer!.shouldRasterize = false
-        layer!.delegate = NoAnimationDelegate.shared
         layerContentsRedrawPolicy = .never
-        setupOutlineLayer()
-        setupHandRaisedLayer()
     }
 
-    private func setupOutlineLayer() {
+    override func layout() {
-        outlineLayer = CAShapeLayer()
+        super.layout()
-        outlineLayer.name = "outline"
+        imageLayer.frame = bounds
-        outlineLayer.fillColor = nil
-        outlineLayer.lineWidth = 1.0
-        outlineLayer.lineDashPattern = [4, 3]
-        outlineLayer.lineCap = .round
-        outlineLayer.lineJoin = .round
-        outlineLayer.isHidden = true
-        layer!.addSublayer(outlineLayer)
     }
 
-    private func setupHandRaisedLayer() {
-        guard #available(macOS 11.0, *) else { return }
-        handRaisedLayer = CALayer()
-        handRaisedLayer.contentsGravity = .resizeAspect
-        handRaisedLayer.isHidden = true
-        layer!.addSublayer(handRaisedLayer)
-    }
-
-
-    private func updateOutlineLayer(_ fullyTransparent: Bool) {
-        outlineLayer.isHidden = !fullyTransparent
-        guard fullyTransparent else { return }
-        let inset: CGFloat = 0.5
-        let radius: CGFloat = 8.0
-        let bounds = outlineLayer.superlayer!.bounds
-        outlineLayer.frame = bounds
-        let rect = bounds.insetBy(dx: inset, dy: inset)
-        let path = CGPath(roundedRect: rect, cornerWidth: radius, cornerHeight: radius, transform: nil)
-        outlineLayer.path = path
-        outlineLayer.strokeColor = Appearance.fontColor.cgColor
-    }
-
-    private func updateHandRaisedLayer(_ fullyTransparent: Bool) {
-        guard #available(macOS 11.0, *) else { return }
-        handRaisedLayer.isHidden = !fullyTransparent
-        guard fullyTransparent else { return }
-        // we want the icon to be large but not too large, and readable at small sizes
-        let minSize = min(Appearance.iconSize, bounds.width * 0.9, bounds.height * 0.9)
-        let maxSize = Appearance.iconSize * 3
-        let ratio = min(bounds.width / ThumbnailView.maxThumbnailWidth(), bounds.height / ThumbnailView.maxThumbnailHeight())
-        let pointSize = max(minSize, maxSize * ratio)
-        let config = NSImage.SymbolConfiguration(pointSize: pointSize, weight: .regular)
-        guard let image = NSImage(systemSymbolName: "hand.raised.fill", accessibilityDescription: nil)?.withSymbolConfiguration(config) else { return }
-        handRaisedLayer.contents = image.tinted(Appearance.fontColor)
-        handRaisedLayer.bounds = CGRect(x: 0, y: 0, width: pointSize, height: pointSize)
-        handRaisedLayer.position = CGPoint(x: bounds.midX, y: bounds.midY)
-    }
-
-
     func updateContents(_ caLayerContents: CALayerContents, _ size: NSSize) {
-        var fullyTransparent = false
+        imageLayer.updateContents(caLayerContents, size)
-        switch caLayerContents {
-        case .cgImage(let image?):
-            layer!.contents = image
-            if withTransparencyChecks {
-                fullyTransparent = image.isFullyTransparent()
-            }
-        case .pixelBuffer(let pixelBuffer?):
-            layer!.contents = CVPixelBufferGetIOSurface(pixelBuffer)?.takeUnretainedValue()
-        default: break
-        }
         if frame.size != size {
             frame.size = size
         }
-        if withTransparencyChecks {
-            updateOutlineLayer(fullyTransparent)
-            updateHandRaisedLayer(fullyTransparent)
-        }
     }
 
     func releaseImage() {
-        layer!.contents = nil
+        imageLayer.releaseImage()
     }
 }
 

src/ui/main-window/ThumbnailView.swift

@@ -6,8 +6,8 @@ class ThumbnailView: FlippedView {
     static let extraTextForPadding = "lmnopqrstuvw"
 
     var window_: Window?
-    var thumbnail = LightImageView(withTransparencyChecks: true)
+    var thumbnail = LightImageLayer(withTransparencyChecks: true)
-    var appIcon = LightImageView()
+    var appIcon = LightImageLayer()
     var label = ThumbnailTitleView(font: Appearance.font)
     var statusIcons = StatusIconsView()
     var dockLabelIcon = ThumbnailFilledFontIconView(
@@ -165,13 +165,13 @@ class ThumbnailView: FlippedView {
 
     private func setupSharedSubviews() {
         let shadow = ThumbnailView.makeShadow(Appearance.imagesShadowColor)
-        thumbnail.layer!.masksToBounds = false // let thumbnail shadows show
+        thumbnail.masksToBounds = false // let thumbnail shadows show
-        thumbnail.shadow = shadow
+        thumbnail.applyShadow(shadow)
-        appIcon.shadow = shadow
+        appIcon.applyShadow(shadow)
         dockLabelIcon.shadow = shadow
-        appIcon.setSubviewAbove(dockLabelIcon)
+        layer!.addSublayer(appIcon)
+        addSubview(dockLabelIcon)
         label.fixHeight()
-        setSubviews([appIcon])
     }
 
     private func setupStyleSpecificSubviews() {
@@ -181,8 +181,9 @@ class ThumbnailView: FlippedView {
             label.alignment = .center
             label.isHidden = true
         } else if Preferences.appearanceStyle == .thumbnails {
-            addSubviews([thumbnail, label, statusIcons])
+            layer!.addSublayer(thumbnail)
-            thumbnail.setSubviewAbove(windowlessAppIndicator)
+            addSubviews([label, statusIcons])
+            setSubviewAbove(windowlessAppIndicator)
         } else {
             setSubviewAbove(windowlessAppIndicator)
             addSubviews([label, statusIcons])
@@ -260,7 +261,6 @@ class ThumbnailView: FlippedView {
     private func updateAppIcon(_ element: Window, _ title: String) {
         let appIconSize = ThumbnailView.iconSize()
         appIcon.updateContents(.cgImage(element.icon), appIconSize)
-        appIcon.setAccessibilityLabel(title)
     }
 
     private func updateValues(_ element: Window, _ index: Int, _ newHeight: CGFloat) {
@@ -275,7 +275,6 @@ class ThumbnailView: FlippedView {
                 )
             ))
         )
-        thumbnail.toolTip = element.isWindowlessApp ? ThumbnailView.noOpenWindowToolTip : nil
         if !thumbnail.isHidden {
             if let screenshot = element.thumbnail {
                 let thumbnailSize = ThumbnailView.thumbnailSize(element.size, false)
@@ -285,8 +284,6 @@ class ThumbnailView: FlippedView {
                 let thumbnailSize = ThumbnailView.thumbnailSize(element.icon?.size(), true)
                 thumbnail.updateContents(.cgImage(element.icon), thumbnailSize)
             }
-            // for Accessibility > "speak items under the pointer"
-            thumbnail.setAccessibilityLabel(element.title)
         }
         let title = getAppOrAndWindowTitle()
         let labelChanged = label.stringValue != title
@@ -342,10 +339,12 @@ class ThumbnailView: FlippedView {
         if Preferences.appearanceStyle == .thumbnails {
             let hHeight = max(appIcon.frame.height, ThumbnailsView.layoutCache.labelHeight)
             assignIfDifferent(&thumbnail.frame.origin, NSPoint(x: edgeInsets, y: edgeInsets + hHeight + Appearance.intraCellPadding))
-            thumbnail.centerFrameInParent(x: true)
+            thumbnail.centerInSuperlayer(x: true)
         }
         if !windowlessAppIndicator.isHidden {
-            if Preferences.appearanceStyle != .titles {
+            if Preferences.appearanceStyle == .thumbnails {
+                windowlessAppIndicator.frame.origin.x = thumbnail.frame.origin.x + ((thumbnail.frame.width - windowlessAppIndicator.frame.width) / 2).rounded()
+            } else if Preferences.appearanceStyle != .titles {
                 windowlessAppIndicator.centerFrameInParent(x: true)
             } else {
                 windowlessAppIndicator.frame.origin.x = ((appIcon.frame.width / 2) - (windowlessAppIndicator.frame.width / 2)).rounded()
@@ -354,7 +353,7 @@ class ThumbnailView: FlippedView {
             if Preferences.appearanceStyle != .thumbnails {
                 windowlessAppIndicator.frame.origin.y = windowlessAppIndicator.superview!.frame.height - windowlessAppIndicator.frame.height + 5
             } else {
-                windowlessAppIndicator.frame.origin.y = -5
+                windowlessAppIndicator.frame.origin.y = thumbnail.frame.origin.y - 5
             }
         }
         // we set dockLabelIcon origin, without checking if .isHidden
@@ -432,9 +431,6 @@ class ThumbnailView: FlippedView {
     }
 
     private func observeDragAndDrop() {
-        // NSImageView instances are registered to drag-and-drop by default
-        thumbnail.unregisterDraggedTypes()
-        appIcon.unregisterDraggedTypes()
         // we only handle URLs (i.e. not text, image, or other draggable things)
         registerForDraggedTypes([NSPasteboard.PasteboardType(kUTTypeURL as String)])
     }