feat: Add support for .webp format

Author: MartinZikmund

…ion/Composition/GifFrameProvider.skia.cs …ition/AnimatedImageFrameProvider.skia.cssrc/Uno.UI.Composition/Composition/GifFrameProvider.skia.cs renamed to src/Uno.UI.Composition/Composition/AnimatedImageFrameProvider.skia.cs src/Uno.UI.Composition/Composition/GifFrameProvider.skia.cs renamed to src/Uno.UI.Composition/Composition/AnimatedImageFrameProvider.skia.cs

@@ -8,57 +8,68 @@
 
 namespace Microsoft.UI.Composition;
 
-internal sealed class GifFrameProvider : IFrameProvider
+internal sealed class AnimatedImageFrameProvider : IFrameProvider
 {
 	private readonly SKImage[] _images;
-	private readonly SKCodecFrameInfo[]? _frameInfos;
+	private readonly int[] _durations;
 	private readonly Timer? _timer;
 	private readonly Stopwatch? _stopwatch;
 	private readonly long _totalDuration;
+	private readonly long _memoryPressure;
 	private readonly WeakReference<Action> _onFrameChanged;
 
 	private int _currentFrame;
 	private bool _disposed;
 
-	// Note: The Timer will keep holding onto the ImageFrameProvider until stopped (it's a static root).
-	// But we only stop the timer when we dispose ImageFrameProvider from SkiaCompositionSurface finalizer.
+	// Note: The Timer will keep holding onto the AnimatedImageFrameProvider until stopped (it's a static root).
+	// But we only stop the timer when we dispose AnimatedImageFrameProvider from SkiaCompositionSurface finalizer.
 	// The onFrameChanged Action is also holding onto SkiaCompositionSurface.
-	// So, if ImageFrameProvider holds onto onFrameChanged, the SkiaCompositionSurface is never GC'ed.
+	// So, if AnimatedImageFrameProvider holds onto onFrameChanged, the SkiaCompositionSurface is never GC'ed.
 	// That's why we make it a WeakReference.
 	// Note that SkiaCompositionSurface keeps an unused private field storing onFrameChanged so that it's not GC'ed early.
-	internal GifFrameProvider(SKImage[] images, SKCodecFrameInfo[] frameInfos, long totalDuration, Action onFrameChanged)
+	internal AnimatedImageFrameProvider(SKImage[] images, int[] durations, long totalDuration, Action onFrameChanged)
 	{
 		_images = images;
-		_frameInfos = frameInfos;
+		_durations = durations;
 		_totalDuration = totalDuration;
 		_onFrameChanged = new WeakReference<Action>(onFrameChanged);
 		Debug.Assert(images.Length > 1);
-		Debug.Assert(frameInfos is not null);
+		Debug.Assert(durations is not null);
+		Debug.Assert(durations.Length == images.Length);
 		Debug.Assert(totalDuration != 0);
 		Debug.Assert(onFrameChanged is not null);
 
 		if (_images.Length < 2)
 		{
-			throw new ArgumentException("GifFrameProvider should only be used when there is at least two frames");
+			throw new ArgumentException("AnimatedImageFrameProvider should only be used when there is at least two frames");
 		}
 
+		long pressure = 0;
+		for (int i = 0; i < _images.Length; i++)
+		{
+			pressure += _images[i].Info.BytesSize;
+		}
+
+		_memoryPressure = pressure;
+		GC.AddMemoryPressure(_memoryPressure);
+
 		_stopwatch = Stopwatch.StartNew();
-		_timer = new Timer(OnTimerCallback, null, dueTime: _frameInfos![0].Duration, period: Timeout.Infinite);
+		_timer = new Timer(OnTimerCallback, null, dueTime: _durations[0], period: Timeout.Infinite);
 	}
 
 	public SKImage? CurrentImage => _images[_currentFrame];
 
 	private int GetCurrentFrameIndex()
 	{
 		var currentTimestampInMilliseconds = _stopwatch!.ElapsedMilliseconds % _totalDuration;
-		for (int i = 0; i < _frameInfos!.Length; i++)
+		for (int i = 0; i < _durations.Length; i++)
 		{
-			if (currentTimestampInMilliseconds < _frameInfos[i].Duration)
+			if (currentTimestampInMilliseconds < _durations[i])
 			{
 				return i;
 			}
 
-			currentTimestampInMilliseconds -= _frameInfos[i].Duration;
+			currentTimestampInMilliseconds -= _durations[i];
 		}
 
 		throw new InvalidOperationException("This shouldn't be reachable. A timestamp in total duration range should map to a frame");
@@ -86,7 +97,7 @@ private void OnTimerCallback(object? state)
 		var nextFrameTimeStamp = 0;
 		for (int i = 0; i <= _currentFrame; i++)
 		{
-			nextFrameTimeStamp += _frameInfos![i].Duration;
+			nextFrameTimeStamp += _durations[i];
 		}
 
 		var dueTime = nextFrameTimeStamp - timestamp;
@@ -109,8 +120,15 @@ public void Dispose()
 	{
 		if (!_disposed)
 		{
-			_timer?.Dispose();
 			_disposed = true;
+			_timer?.Dispose();
+
+			for (int i = 0; i < _images.Length; i++)
+			{
+				_images[i].Dispose();
+			}
+
+			GC.RemoveMemoryPressure(_memoryPressure);
 		}
 	}
 }

src/Uno.UI.Composition/Composition/FrameProviderFactory.skia.cs

@@ -36,10 +36,30 @@ public static bool TryCreate(SKManagedStream stream, Action onFrameChanged, [Not
 		}
 
 		var images = GC.AllocateUninitializedArray<SKImage>(frameInfos.Length);
+		var durations = new int[frameInfos.Length];
 		var totalDuration = 0;
+
 		for (int i = 0; i < frameInfos.Length; i++)
 		{
-			var options = new SKCodecOptions(i);
+			var requiredFrame = frameInfos[i].RequiredFrame;
+
+			if (requiredFrame == -1)
+			{
+				// Independent frame - clear the bitmap before decoding.
+				bitmap.Erase(SKColor.Empty);
+			}
+			else if (requiredFrame != i - 1)
+			{
+				// The required frame is not the immediately preceding one, so we
+				// need to restore its pixels into the bitmap before decoding.
+				using var restoreCanvas = new SKCanvas(bitmap);
+				restoreCanvas.Clear(SKColor.Empty);
+				restoreCanvas.DrawImage(images[requiredFrame], 0, 0);
+			}
+			// When requiredFrame == i - 1, the bitmap already contains the
+			// correct prior frame pixels from the previous iteration.
+
+			var options = new SKCodecOptions(i, requiredFrame);
 			codec.GetPixels(imageInfo, bitmap.GetPixels(), options);
 
 			var currentBitmap = GetImage(bitmap, codec.EncodedOrigin);
@@ -50,10 +70,15 @@ public static bool TryCreate(SKManagedStream stream, Action onFrameChanged, [Not
 			}
 
 			images[i] = currentBitmap;
-			totalDuration += frameInfos[i].Duration;
+
+			// Clamp zero-duration frames to 100ms to prevent division-by-zero
+			// and match common animated image behavior.
+			var duration = frameInfos[i].Duration;
+			durations[i] = duration > 0 ? duration : 100;
+			totalDuration += durations[i];
 		}
 
-		provider = new GifFrameProvider(images, frameInfos, totalDuration, onFrameChanged);
+		provider = new AnimatedImageFrameProvider(images, durations, totalDuration, onFrameChanged);
 		return true;
 	}
 
@@ -98,16 +123,16 @@ private static SKMatrix GetExifMatrix(SKEncodedOrigin origin, int width, int hei
 	private static bool SkEncodedOriginSwapsWidthHeight(SKEncodedOrigin origin)
 	{
 		return origin is
-			// Reflected across x - axis.Rotated 90° counter - clockwise.
+			// Reflected across x - axis.Rotated 90� counter - clockwise.
 			SKEncodedOrigin.LeftTop or
 
-			// Rotated 90° clockwise.
+			// Rotated 90� clockwise.
 			SKEncodedOrigin.RightTop or
 
-			// Reflected across x-axis. Rotated 90° clockwise.
+			// Reflected across x-axis. Rotated 90� clockwise.
 			SKEncodedOrigin.RightBottom or
 
-			// Rotated 90° counter-clockwise.
+			// Rotated 90� counter-clockwise.
 			SKEncodedOrigin.LeftBottom;
 	}
 

src/Uno.UI/UI/Xaml/Media/Imaging/ImageSourceHelpers.cs

@@ -129,13 +129,23 @@ public static async Task<ImageData> GetImageDataFromUriAsCompositionSurface(Uri
 		try
 		{
 			using var stream = await AppDataUriEvaluator.ToStream(uri, ct);
-			// add more animation formats here if needed
-			return await ReadFromStreamAsCompositionSurface(stream, ct, !uri.AbsolutePath.EndsWith(".gif", StringComparison.InvariantCultureIgnoreCase));
+			return await ReadFromStreamAsCompositionSurface(stream, ct, !IsAnimatableImageFormat(uri));
 		}
 		catch (Exception e)
 		{
 			return ImageData.FromError(e);
 		}
 	}
+
+	/// <summary>
+	/// Returns true for image formats that may contain animation and must bypass the
+	/// browser Canvas API (which only returns the first frame) in favor of SKCodec.
+	/// </summary>
+	private static bool IsAnimatableImageFormat(Uri uri)
+	{
+		var path = uri.AbsolutePath;
+		return path.EndsWith(".gif", StringComparison.OrdinalIgnoreCase)
+			|| path.EndsWith(".webp", StringComparison.OrdinalIgnoreCase);
+	}
 #endif
 }