chore: fix ellipse & rectangle shadow shape

src/Uno.Toolkit.Skia.WinUI/Controls/Shadows/ShadowContainer.Paint.cs

@@ -133,19 +133,21 @@ private void OnSurfacePainted(object? sender, SKPaintSurfaceEventArgs e)
 		};
 	}
 
-	private IShadowShapeContext GetShadowShapeContext(object? content)
+	private IShadowShapeContext GetShadowShapeContext(object content)
 	{
 		return content switch
 		{
-			FrameworkElement fe => new RectangularShadowShapeContext(fe.ActualWidth, fe.ActualHeight, GetCornerRadiusFor(Content) ?? default),
+			// any dp used here, beside width/height that is covered by SizeChanged, needs to register for dp changed in: BindToPaintingProperties\BindToContent()
+			Ellipse ellipse => new RadiusXYRectShadowShapeContext(ellipse.ActualWidth, ellipse.ActualHeight, ellipse.ActualWidth / 2, ellipse.ActualHeight / 2),
+			Rectangle rect => new RadiusXYRectShadowShapeContext(rect.ActualWidth, rect.ActualHeight, rect.RadiusX, rect.RadiusY),
+			FrameworkElement fe => new CornerRadiusRectShadowShapeContext(fe.ActualWidth, fe.ActualHeight, GetCornerRadiusFor(Content) ?? default),
 
-			null => RectangularShadowShapeContext.Empty,
 			_ => throw new NotSupportedException($"Unsupported content type: {content.GetType().Name}"),
 		};
 	}
 
 	/// <summary>
-	/// Serves both as a record of states relevant to shadow shape, and the implementations for painting the shadows
+	/// Serves both as a record of states relevant to shadow shape (not <see cref="Shape"/>, but in the broad sense), and the implementations for painting the shadows.
 	/// </summary>
 	private interface IShadowShapeContext
 	{
@@ -158,17 +160,9 @@ private interface IShadowShapeContext
 		void DrawInnerShadow(ShadowPaintState state, SKCanvas canvas, SKPaint paint, ShadowInfo shadow);
 	}
 
-	private record RectangularShadowShapeContext(double ContentWidth, double ContentHeight, CornerRadius CornerRadius) : IShadowShapeContext
+	private abstract record RoundRectShadowShapeContext(double Width, double Height) : IShadowShapeContext
 	{
-		public static readonly RectangularShadowShapeContext Empty = new(0, 0, default);
-
-		private SKRoundRect GetContentShape(ShadowPaintState state)
-		{
-			var rect = new SKRect(0, 0, (float)ContentWidth * state.PixelRatio, (float)ContentHeight * state.PixelRatio);
-			var shape = new SKRoundRect(rect, (float)CornerRadius.BottomRight * state.PixelRatio);
-
-			return shape;
-		}
+		protected abstract SKRoundRect GetContentShape(ShadowPaintState state);
 
 		public void ClipToContent(ShadowPaintState state, SKCanvas canvas)
 		{
@@ -231,7 +225,6 @@ public void DrawDropShadow(ShadowPaintState state, SKCanvas canvas, SKPaint pain
 
 		public void DrawInnerShadow(ShadowPaintState state, SKCanvas canvas, SKPaint paint, ShadowInfo shadow)
 		{
-			var cornerRadius = (float)CornerRadius.BottomRight * state.PixelRatio;
 			var spread = (float)shadow.Spread * state.PixelRatio;
 			var offsetX = (float)shadow.OffsetX * state.PixelRatio;
 			var offsetY = (float)shadow.OffsetY * state.PixelRatio;
@@ -253,12 +246,39 @@ public void DrawInnerShadow(ShadowPaintState state, SKCanvas canvas, SKPaint pai
 
 			if (_logger.IsEnabled(LogLevel.Trace))
 			{
-				_logger.Trace($"[ShadowContainer] DrawInnerShadow => strokeWidth: {paint.StrokeWidth}, cornerRadius: {cornerRadius}, x: {offsetX}, y: {offsetY}, width: {shape.Rect.Width}, height: {shape.Rect.Height}");
+				_logger.Trace($"[ShadowContainer] DrawInnerShadow => strokeWidth: {paint.StrokeWidth}, x: {offsetX}, y: {offsetY}, width: {shape.Rect.Width}, height: {shape.Rect.Height}");
 			}
 			canvas.DrawRoundRect(shape, paint);
 		}
 	}
 
+	private record CornerRadiusRectShadowShapeContext(double Width, double Height, CornerRadius CornerRadius) : RoundRectShadowShapeContext(Width, Height)
+	{
+		protected override SKRoundRect GetContentShape(ShadowPaintState state)
+		{
+			var rect = new SKRect(0, 0, (float)Width * state.PixelRatio, (float)Height * state.PixelRatio);
+			var radii = new[] { CornerRadius.TopLeft, CornerRadius.TopRight, CornerRadius.BottomRight, CornerRadius.BottomLeft }
+				.Select(x => (float)x * state.PixelRatio)
+				.Select(x => new SKPoint(x, x))
+				.ToArray();
+			var shape = new SKRoundRect();
+			shape.SetRectRadii(rect, radii);
+
+			return shape;
+		}
+	}
+
+	private record RadiusXYRectShadowShapeContext(double Width, double Height, double RadiusX, double RadiusY) : RoundRectShadowShapeContext(Width, Height)
+	{
+		protected override SKRoundRect GetContentShape(ShadowPaintState state)
+		{
+			var rect = new SKRect(0, 0, (float)Width * state.PixelRatio, (float)Height * state.PixelRatio);
+			var shape = new SKRoundRect(rect, (float)RadiusX * state.PixelRatio, (float)RadiusY * state.PixelRatio);
+
+			return shape;
+		}
+	}
+
 	/// <summary>
 	/// Record of <see cref="Shadow"/> properties at one point in time.
 	/// </summary>

src/Uno.Toolkit.Skia.WinUI/Controls/Shadows/ShadowContainer.cs

@@ -118,10 +118,6 @@ void OnShadowPropertyChanged(object? sender, PropertyChangedEventArgs e)
 		}
 		void OnInnerPropertyChanged(DependencyObject sender, DependencyProperty dp)
 		{
-			if (sender == this && dp == CornerRadiusProperty)
-			{
-				InvalidateCanvasLayout();
-			}
 			InvalidateShadows();
 		}
 		void OnContentPropertyChanged(DependencyObject sender, DependencyProperty dp)
@@ -207,13 +203,29 @@ void BindToContent(object? content)
 		{
 			if (content is FrameworkElement contentAsFE)
 			{
-				contentAsFE.SizeChanged += OnContentSizeChanged;
 				contentNestedDisposable.Disposable = new CompositeDisposable
 				{
-					Disposable.Create(() => contentAsFE.SizeChanged -= OnContentSizeChanged),
-					GetCornerRadiusPropertyFor(content) is { } dp ? contentAsFE.RegisterDisposablePropertyChangedCallback(dp, OnContentPropertyChanged) : Disposable.Empty,
-					contentAsFE.RegisterDisposablePropertyChangedCallback(FrameworkElement.MarginProperty, OnContentPropertyChanged),
+					RegisterSizeChangedHandler(contentAsFE, OnContentSizeChanged),
+					RegisterNestedPropertyChangedSafe<FrameworkElement>(GetCornerRadiusPropertyFor(content)),
+					RegisterNestedPropertyChangedSafe<Rectangle>(Rectangle.RadiusXProperty),
+					RegisterNestedPropertyChangedSafe<Rectangle>(Rectangle.RadiusYProperty),
+					RegisterNestedPropertyChangedSafe<FrameworkElement>(FrameworkElement.MarginProperty),
 				};
+
+				static IDisposable RegisterSizeChangedHandler(FrameworkElement fe, SizeChangedEventHandler handler)
+				{
+					fe.SizeChanged += handler;
+					return Disposable.Create(() => fe.SizeChanged -= handler);
+				}
+				IDisposable RegisterNestedPropertyChangedSafe<T>(DependencyProperty? dp, DependencyPropertyChangedCallback? callback = null)
+				{
+					if (contentAsFE is T && dp is { })
+					{
+						return contentAsFE.RegisterDisposablePropertyChangedCallback(dp, callback ?? OnContentPropertyChanged);
+					}
+
+					return Disposable.Empty;
+				}
 			}
 			else
 			{
@@ -377,7 +389,7 @@ private void InvalidateShadows(bool force = false)
 			Grid => Grid.CornerRadiusProperty,
 			StackPanel => StackPanel.CornerRadiusProperty,
 
-			Shape => null,
+			Shape => null, // note: shapes have special handling, see: GetShadowShapeContext
 			DependencyObject @do => @do.FindDependencyPropertyUsingReflection<CornerRadius>("CornerRadiusProperty"),
 			_ => null,
 		};
@@ -392,18 +404,11 @@ private void InvalidateShadows(bool force = false)
 			Border border => border.CornerRadius,
 			Grid grid => grid.CornerRadius,
 			StackPanel stackpanel => stackpanel.CornerRadius,
-			Rectangle border => new CornerRadius(border.RadiusY == 0 ? 0 : (border.RadiusX / border.RadiusY) * (border.Width > border.Height ? border.Width : border.Height)),
-			Ellipse ellipse => new CornerRadius(ellipse.Height == 0 ? 0 : (ellipse.Width / ellipse.Height / 2) * (ellipse.Width > ellipse.Height ? ellipse.Width : ellipse.Height)),
 
-			Shape => null,
-			DependencyObject @do =>
-				@do.FindDependencyPropertyUsingReflection<CornerRadius>("CornerRadiusProperty") is { } dp
+			Shape => null, // note: shapes have special handling, see: GetShadowShapeContext
+			DependencyObject @do => @do.FindDependencyPropertyUsingReflection<CornerRadius>("CornerRadiusProperty") is { } dp
 				? (CornerRadius)@do.GetValue(dp)
-				:
-					//@do.FindDependencyPropertyUsingReflection<CornerRadius>("RadiusXProperty") is { } radiusX
-					//? (CornerRadius)new CornerRadius((double)@do.GetValue(radiusX))
-					//:
-				null,
+				: null,
 			_ => null,
 		};
 	}