Fixed animation issues when do fast switching animation style

Author: Bohdan

LanguageFlag/Animations/Core/AnimationCoordinator.swift

@@ -8,6 +8,11 @@ final class AnimationCoordinator {
     private let preferences = UserPreferences.shared
     private var isShowing = false
 
+    /// Generation counter that increments on each animateIn, used to invalidate
+    /// stale animateOut completion blocks that would otherwise hide the window
+    /// after a new animation has already started.
+    private var generation: Int = 0
+
     // Animation styles that need frame setup before animation
     private let stylesNeedingFrameSetup: Set<AnimationStyle> = [
         .slide, .scale, .pixelate, .bounce, .flip, .swing, .elastic,
@@ -32,14 +37,18 @@ final class AnimationCoordinator {
         window: NSWindow,
         style: AnimationStyle,
         duration: TimeInterval,
-        screenRect: CGRect
+        screenRect: CGRect,
+        force: Bool = false
     ) {
         // If the window is already showing and reset is disabled,
-        // let the current animation continue.
+        // let the current animation continue unless forced (e.g., style preview).
         // The flag image/title will still update (handled by LanguageViewController).
-        if isShowing, !preferences.resetAnimationOnChange { return }
+        if isShowing, !preferences.resetAnimationOnChange, !force { return }
         isShowing = true
 
+        // Increment generation so any in-flight animateOut completions become no-ops
+        generation += 1
+
         // Set opacity before animation if window is being shown for first time
         if window.alphaValue == 0 {
             window.alphaValue = CGFloat(preferences.opacity)
@@ -75,8 +84,17 @@ final class AnimationCoordinator {
     ) {
         isShowing = false
 
+        // Capture the current generation so the completion block can verify
+        // that no new animateIn has started since this animateOut was dispatched.
+        let capturedGeneration = generation
+
         let frameResetCompletion: (() -> Void)? = stylesNeedingFrameReset.contains(style) ? { [weak self] in
             guard let self = self else { return }
+
+            // If a new animateIn has started since this animateOut was dispatched,
+            // skip the cleanup to avoid hiding the newly-shown window.
+            guard self.generation == capturedGeneration else { return }
+
             let targetFrame = self.positionCalculator.calculateWindowFrame(
                 in: screenRect,
                 position: self.preferences.displayPosition,

LanguageFlag/Animations/Core/BaseWindowAnimation.swift

@@ -12,6 +12,7 @@ class BaseWindowAnimation {
     /// - Returns: The prepared CALayer, or nil if preparation fails
     func prepareLayer(from window: NSWindow) -> CALayer? {
         guard let contentView = window.contentView else { return nil }
+
         contentView.wantsLayer = true
         return contentView.layer
     }
@@ -79,6 +80,7 @@ class BaseWindowAnimation {
         animation.toValue = to
         animation.duration = duration
         animation.timingFunction = timing
+
         return animation
     }
 
@@ -97,10 +99,29 @@ class BaseWindowAnimation {
         timing: CAMediaTimingFunction = CAMediaTimingFunction(name: .easeOut)
     ) {
         contentView.alphaValue = from
+
         NSAnimationContext.runAnimationGroup { context in
             context.duration = duration
             context.timingFunction = timing
             contentView.animator().alphaValue = to
         }
     }
 }
+
+/// Delegate helper to handle CAAnimation completion reliably across animation overrides
+class AnimationCompletionDelegate: NSObject, CAAnimationDelegate {
+
+    // MARK: - Properties
+    private let completion: (Bool) -> Void
+
+    // MARK: - Initialization
+    init(completion: @escaping (Bool) -> Void) {
+        self.completion = completion
+        super.init()
+    }
+
+    // MARK: - CAAnimationDelegate
+    func animationDidStop(_ anim: CAAnimation, finished flag: Bool) {
+        completion(flag)
+    }
+}

LanguageFlag/Animations/FilterBased/BlurAnimation.swift

@@ -18,22 +18,24 @@ class BlurAnimation: BaseWindowAnimation, WindowAnimation {
         let blurFilter = FilterBuilder.gaussianBlur(radius: 0.0)
         applyFilters([blurFilter], to: layer)
 
-        CATransaction.begin()
-        CATransaction.setAnimationDuration(duration)
-        CATransaction.setAnimationTimingFunction(AnimationTiming.easeOut)
-        CATransaction.setCompletionBlock {
-            self.clearFilters(from: layer)
-            completion?()
-        }
-        
-        let animation = createAnimation(
+        let blurAnim = createAnimation(
             keyPath: "filters.CIGaussianBlur.inputRadius",
             from: 20.0,
             to: 0.0,
             duration: duration
         )
-        layer.add(animation, forKey: "blur")
-        
+        blurAnim.fillMode = .forwards
+        blurAnim.isRemovedOnCompletion = false
+        blurAnim.delegate = AnimationCompletionDelegate { [weak self] finished in
+            guard let self, finished else { return }
+            self.clearFilters(from: layer)
+            completion?()
+        }
+
+        CATransaction.begin()
+        CATransaction.setAnimationDuration(duration)
+        CATransaction.setAnimationTimingFunction(AnimationTiming.easeOut)
+        layer.add(blurAnim, forKey: "blur")
         CATransaction.commit()
 
         animateAlpha(contentView: contentView, from: 0.0, to: 1.0, duration: duration)
@@ -51,23 +53,25 @@ class BlurAnimation: BaseWindowAnimation, WindowAnimation {
         let blurFilter = FilterBuilder.gaussianBlur(radius: 20.0)
         applyFilters([blurFilter], to: layer)
 
-        CATransaction.begin()
-        CATransaction.setAnimationDuration(duration)
-        CATransaction.setAnimationTimingFunction(AnimationTiming.easeIn)
-        CATransaction.setCompletionBlock {
-            self.clearFilters(from: layer)
-            completion?()
-        }
-        
-        let animation = createAnimation(
+        let blurAnim = createAnimation(
             keyPath: "filters.CIGaussianBlur.inputRadius",
             from: 0.0,
             to: 20.0,
             duration: duration,
             timing: AnimationTiming.easeIn
         )
-        layer.add(animation, forKey: "blur")
-        
+        blurAnim.fillMode = .forwards
+        blurAnim.isRemovedOnCompletion = false
+        blurAnim.delegate = AnimationCompletionDelegate { [weak self] finished in
+            guard let self, finished else { return }
+            self.clearFilters(from: layer)
+            completion?()
+        }
+
+        CATransaction.begin()
+        CATransaction.setAnimationDuration(duration)
+        CATransaction.setAnimationTimingFunction(AnimationTiming.easeIn)
+        layer.add(blurAnim, forKey: "blur")
         CATransaction.commit()
 
         animateAlpha(

LanguageFlag/Animations/FilterBased/DigitalMaterializeAnimation.swift

@@ -32,16 +32,17 @@ class DigitalMaterializeAnimation: BaseWindowAnimation, WindowAnimation {
         CATransaction.begin()
         CATransaction.setAnimationDuration(duration)
         CATransaction.setAnimationTimingFunction(AnimationTiming.linear)
-        CATransaction.setCompletionBlock {
-            layer.mask = nil
-            self.clearFilters(from: layer)
-            completion?()
-        }
 
         // Animate Mask from bottom to top (build up)
         let maskAnim = createAnimation(keyPath: "locations", from: [0.95, 1.0, 1.0], to: [0.0, 0.0, 0.05], duration: duration)
         maskAnim.fillMode = .forwards
         maskAnim.isRemovedOnCompletion = false
+        maskAnim.delegate = AnimationCompletionDelegate { [weak self] finished in
+            guard let self, finished else { return }
+            layer.mask = nil
+            self.clearFilters(from: layer)
+            completion?()
+        }
         maskLayer.add(maskAnim, forKey: "scanline")
         maskLayer.locations = [0.0, 0.0, 0.05] // Final state (Model matches End for Mask, but safe to persist)
 
@@ -88,16 +89,17 @@ class DigitalMaterializeAnimation: BaseWindowAnimation, WindowAnimation {
         CATransaction.begin()
         CATransaction.setAnimationDuration(duration)
         CATransaction.setAnimationTimingFunction(AnimationTiming.linear)
-        CATransaction.setCompletionBlock {
-            layer.mask = nil
-            self.clearFilters(from: layer)
-            completion?()
-        }
 
         // Animate Mask from top to bottom (dematerialize)
         let maskAnim = createAnimation(keyPath: "locations", from: [0.0, 0.0, 0.05], to: [0.95, 1.0, 1.0], duration: duration)
         maskAnim.fillMode = .forwards
         maskAnim.isRemovedOnCompletion = false
+        maskAnim.delegate = AnimationCompletionDelegate { [weak self] finished in
+            guard let self, finished else { return }
+            layer.mask = nil
+            self.clearFilters(from: layer)
+            completion?()
+        }
         maskLayer.add(maskAnim, forKey: "scanline")
         maskLayer.locations = [0.95, 1.0, 1.0] // Final state
 

LanguageFlag/Animations/FilterBased/EnergyPortalAnimation.swift

@@ -29,15 +29,16 @@ class EnergyPortalAnimation: BaseWindowAnimation, WindowAnimation {
         CATransaction.begin()
         CATransaction.setAnimationDuration(duration)
         CATransaction.setAnimationTimingFunction(AnimationTiming.easeOut)
-        CATransaction.setCompletionBlock {
-            self.clearFilters(from: layer)
-            completion?()
-        }
 
         // Animate twirl (3pi -> 0)
         let twirlAnim = createAnimation(keyPath: "filters.CITwirlDistortion.inputAngle", from: CGFloat.pi * 3, to: 0.0, duration: duration)
         twirlAnim.fillMode = .forwards
         twirlAnim.isRemovedOnCompletion = false
+        twirlAnim.delegate = AnimationCompletionDelegate { [weak self] finished in
+            guard let self, finished else { return }
+            self.clearFilters(from: layer)
+            completion?()
+        }
         layer.add(twirlAnim, forKey: "twirl")
 
         // Animate zoom (30 -> 0)
@@ -85,15 +86,16 @@ class EnergyPortalAnimation: BaseWindowAnimation, WindowAnimation {
         CATransaction.begin()
         CATransaction.setAnimationDuration(duration)
         CATransaction.setAnimationTimingFunction(AnimationTiming.easeIn)
-        CATransaction.setCompletionBlock {
-            self.clearFilters(from: layer)
-            completion?()
-        }
 
         // Animate twirl (0 -> 3pi)
         let twirlAnim = createAnimation(keyPath: "filters.CITwirlDistortion.inputAngle", from: 0.0, to: CGFloat.pi * 3, duration: duration)
         twirlAnim.fillMode = .forwards
         twirlAnim.isRemovedOnCompletion = false
+        twirlAnim.delegate = AnimationCompletionDelegate { [weak self] finished in
+            guard let self, finished else { return }
+            self.clearFilters(from: layer)
+            completion?()
+        }
         layer.add(twirlAnim, forKey: "twirl")
 
         // Animate zoom (0 -> 30)

LanguageFlag/Animations/FilterBased/HologramAnimation.swift

@@ -26,18 +26,16 @@ class HologramAnimation: BaseWindowAnimation, WindowAnimation {
         CATransaction.begin()
         CATransaction.setAnimationDuration(duration)
         CATransaction.setAnimationTimingFunction(AnimationTiming.easeOut)
-        CATransaction.setCompletionBlock {
-            // Legacy: Explicitly set final values before clearing?
-            // Since we conform to Strategy, clearing is standard.
-            // But we use fillMode.forwards to hold until clear.
-            self.clearFilters(from: layer)
-            completion?()
-        }
 
         // Animate pixelation (8.0 -> 1.0)
         let pixelAnim = createAnimation(keyPath: "filters.CIPixellate.inputScale", from: 8.0, to: 1.0, duration: duration)
         pixelAnim.fillMode = .forwards
         pixelAnim.isRemovedOnCompletion = false
+        pixelAnim.delegate = AnimationCompletionDelegate { [weak self] finished in
+            guard let self, finished else { return }
+            self.clearFilters(from: layer)
+            completion?()
+        }
         layer.add(pixelAnim, forKey: "pixel")
 
         // Animate saturation (1.5 -> 1.0)
@@ -82,15 +80,16 @@ class HologramAnimation: BaseWindowAnimation, WindowAnimation {
         CATransaction.begin()
         CATransaction.setAnimationDuration(duration)
         CATransaction.setAnimationTimingFunction(AnimationTiming.easeIn)
-        CATransaction.setCompletionBlock {
-            self.clearFilters(from: layer)
-            completion?()
-        }
 
         // Animate pixelation (1.0 -> 8.0)
         let pixelAnim = createAnimation(keyPath: "filters.CIPixellate.inputScale", from: 1.0, to: 8.0, duration: duration)
         pixelAnim.fillMode = .forwards
         pixelAnim.isRemovedOnCompletion = false
+        pixelAnim.delegate = AnimationCompletionDelegate { [weak self] finished in
+            guard let self, finished else { return }
+            self.clearFilters(from: layer)
+            completion?()
+        }
         layer.add(pixelAnim, forKey: "pixel")
 
         // Animate saturation (1.0 -> 1.5)

LanguageFlag/Animations/FilterBased/InkDiffusionAnimation.swift

@@ -25,14 +25,15 @@ class InkDiffusionAnimation: BaseWindowAnimation, WindowAnimation {
         CATransaction.begin()
         CATransaction.setAnimationDuration(duration)
         CATransaction.setAnimationTimingFunction(AnimationTiming.easeOut)
-        CATransaction.setCompletionBlock {
-            self.clearFilters(from: layer)
-            completion?()
-        }
 
         let morphAnim = createAnimation(keyPath: "filters.CIMorphologyMaximum.inputRadius", from: 10.0, to: 0.0, duration: duration)
         morphAnim.fillMode = .forwards
         morphAnim.isRemovedOnCompletion = false
+        morphAnim.delegate = AnimationCompletionDelegate { [weak self] finished in
+            guard let self, finished else { return }
+            self.clearFilters(from: layer)
+            completion?()
+        }
         layer.add(morphAnim, forKey: "morph")
 
         let blurAnim = createAnimation(keyPath: "filters.CIGaussianBlur.inputRadius", from: 15.0, to: 0.0, duration: duration)
@@ -70,14 +71,15 @@ class InkDiffusionAnimation: BaseWindowAnimation, WindowAnimation {
         CATransaction.begin()
         CATransaction.setAnimationDuration(duration)
         CATransaction.setAnimationTimingFunction(AnimationTiming.easeIn)
-        CATransaction.setCompletionBlock {
-            self.clearFilters(from: layer)
-            completion?()
-        }
 
         let morphAnim = createAnimation(keyPath: "filters.CIMorphologyMaximum.inputRadius", from: 0.0, to: 10.0, duration: duration)
         morphAnim.fillMode = .forwards
         morphAnim.isRemovedOnCompletion = false
+        morphAnim.delegate = AnimationCompletionDelegate { [weak self] finished in
+            guard let self, finished else { return }
+            self.clearFilters(from: layer)
+            completion?()
+        }
         layer.add(morphAnim, forKey: "morph")
 
         let blurAnim = createAnimation(keyPath: "filters.CIGaussianBlur.inputRadius", from: 0.0, to: 15.0, duration: duration)

LanguageFlag/Animations/FilterBased/LiquidRippleAnimation.swift

@@ -25,15 +25,16 @@ class LiquidRippleAnimation: BaseWindowAnimation, WindowAnimation {
         CATransaction.begin()
         CATransaction.setAnimationDuration(duration)
         CATransaction.setAnimationTimingFunction(AnimationTiming.easeOut)
-        CATransaction.setCompletionBlock {
-            self.clearFilters(from: layer)
-            completion?()
-        }
 
         // Animate splash radius (150 -> 0)
         let splashAnim = createAnimation(keyPath: "filters.CICircleSplashDistortion.inputRadius", from: 150.0, to: 0.0, duration: duration)
         splashAnim.fillMode = .forwards
         splashAnim.isRemovedOnCompletion = false
+        splashAnim.delegate = AnimationCompletionDelegate { [weak self] finished in
+            guard let self, finished else { return }
+            self.clearFilters(from: layer)
+            completion?()
+        }
         layer.add(splashAnim, forKey: "splash")
 
         CATransaction.commit()
@@ -60,15 +61,16 @@ class LiquidRippleAnimation: BaseWindowAnimation, WindowAnimation {
         CATransaction.begin()
         CATransaction.setAnimationDuration(duration)
         CATransaction.setAnimationTimingFunction(AnimationTiming.easeIn)
-        CATransaction.setCompletionBlock {
-            self.clearFilters(from: layer)
-            completion?()
-        }
 
         // Animate splash radius (0 -> 150)
         let splashAnim = createAnimation(keyPath: "filters.CICircleSplashDistortion.inputRadius", from: 0.0, to: 150.0, duration: duration)
         splashAnim.fillMode = .forwards
         splashAnim.isRemovedOnCompletion = false
+        splashAnim.delegate = AnimationCompletionDelegate { [weak self] finished in
+            guard let self, finished else { return }
+            self.clearFilters(from: layer)
+            completion?()
+        }
         layer.add(splashAnim, forKey: "splash")
 
         CATransaction.commit()