Introduce RenderOptions.RequiresFullOpacityHandling

src/Avalonia.Base/Media/RenderOptions.cs

@@ -8,12 +8,13 @@ namespace Avalonia.Media
         public EdgeMode EdgeMode { get; init; }
         public TextRenderingMode TextRenderingMode { get; init; }
         public BitmapBlendingMode BitmapBlendingMode { get; init; }
+        public bool? RequiresFullOpacityHandling { get; init; }
 
         /// <summary>
         /// Gets the value of the BitmapInterpolationMode attached property for a visual.
         /// </summary>
         /// <param name="visual">The control.</param>
-        /// <returns>The control's left coordinate.</returns>
+        /// <returns>The value.</returns>
         public static BitmapInterpolationMode GetBitmapInterpolationMode(Visual visual)
         {
             return visual.RenderOptions.BitmapInterpolationMode;
@@ -23,7 +24,7 @@ namespace Avalonia.Media
         /// Sets the value of the BitmapInterpolationMode attached property for a visual.
         /// </summary>
         /// <param name="visual">The control.</param>
-        /// <param name="value">The left value.</param>
+        /// <param name="value">The value.</param>
         public static void SetBitmapInterpolationMode(Visual visual, BitmapInterpolationMode value)
         {
             visual.RenderOptions = visual.RenderOptions with { BitmapInterpolationMode = value };
@@ -33,7 +34,7 @@ namespace Avalonia.Media
         /// Gets the value of the BitmapBlendingMode attached property for a visual.
         /// </summary>
         /// <param name="visual">The control.</param>
-        /// <returns>The control's left coordinate.</returns>
+        /// <returns>The value.</returns>
         public static BitmapBlendingMode GetBitmapBlendingMode(Visual visual)
         {
             return visual.RenderOptions.BitmapBlendingMode;
@@ -53,7 +54,7 @@ namespace Avalonia.Media
         /// Gets the value of the EdgeMode attached property for a visual.
         /// </summary>
         /// <param name="visual">The control.</param>
-        /// <returns>The control's left coordinate.</returns>
+        /// <returns>The value.</returns>
         public static EdgeMode GetEdgeMode(Visual visual)
         {
             return visual.RenderOptions.EdgeMode;
@@ -63,7 +64,7 @@ namespace Avalonia.Media
         /// Sets the value of the EdgeMode attached property for a visual.
         /// </summary>
         /// <param name="visual">The control.</param>
-        /// <param name="value">The left value.</param>
+        /// <param name="value">The value.</param>
         public static void SetEdgeMode(Visual visual, EdgeMode value)
         {
             visual.RenderOptions = visual.RenderOptions with { EdgeMode = value };
@@ -73,7 +74,7 @@ namespace Avalonia.Media
         /// Gets the value of the TextRenderingMode attached property for a visual.
         /// </summary>
         /// <param name="visual">The control.</param>
-        /// <returns>The control's left coordinate.</returns>
+        /// <returns>The value.</returns>
         public static TextRenderingMode GetTextRenderingMode(Visual visual)
         {
             return visual.RenderOptions.TextRenderingMode;
@@ -83,12 +84,32 @@ namespace Avalonia.Media
         /// Sets the value of the TextRenderingMode attached property for a visual.
         /// </summary>
         /// <param name="visual">The control.</param>
-        /// <param name="value">The left value.</param>
+        /// <param name="value">The value.</param>
         public static void SetTextRenderingMode(Visual visual, TextRenderingMode value)
         {
             visual.RenderOptions = visual.RenderOptions with { TextRenderingMode = value };
         }
 
+        /// <summary>
+        /// Gets the value of the RequiresFullOpacityHandling attached property for a visual.
+        /// </summary>
+        /// <param name="visual">The control.</param>
+        /// <returns>The value.</returns>
+        public static bool? GetRequiresFullOpacityHandling(Visual visual)
+        {
+            return visual.RenderOptions.RequiresFullOpacityHandling;
+        }
+
+        /// <summary>
+        /// Sets the value of the RequiresFullOpacityHandling attached property for a visual.
+        /// </summary>
+        /// <param name="visual">The control.</param>
+        /// <param name="value">The value.</param>
+        public static void SetRequiresFullOpacityHandling(Visual visual, bool? value)
+        {
+            visual.RenderOptions = visual.RenderOptions with { RequiresFullOpacityHandling = value };
+        }
+
         public RenderOptions MergeWith(RenderOptions other)
         {
             var bitmapInterpolationMode = BitmapInterpolationMode;
@@ -119,12 +140,20 @@ namespace Avalonia.Media
                 bitmapBlendingMode = other.BitmapBlendingMode;
             }
 
+            var requiresFullOpacityHandling = RequiresFullOpacityHandling;
+
+            if (requiresFullOpacityHandling == null)
+            {
+                requiresFullOpacityHandling = other.RequiresFullOpacityHandling;
+            }
+
             return new RenderOptions
             {
                 BitmapInterpolationMode = bitmapInterpolationMode,
                 EdgeMode = edgeMode,
                 TextRenderingMode = textRenderingMode,
-                BitmapBlendingMode = bitmapBlendingMode
+                BitmapBlendingMode = bitmapBlendingMode,
+                RequiresFullOpacityHandling = requiresFullOpacityHandling
             };
         }
     }

src/Skia/Avalonia.Skia/DrawingContextImpl.cs

@@ -189,7 +189,8 @@ namespace Avalonia.Skia
             var d = destRect.ToSKRect();
 
             var paint = SKPaintCache.Shared.Get();
-            paint.Color = new SKColor(255, 255, 255, (byte)(255 * opacity * (_useOpacitySaveLayer ? 1 : _currentOpacity)));
+
+            paint.Color = new SKColor(255, 255, 255, (byte)(255 * opacity * currentOpacity));
             paint.FilterQuality = RenderOptions.BitmapInterpolationMode.ToSKFilterQuality();
             paint.BlendMode = RenderOptions.BitmapBlendingMode.ToSKBlendMode();
 
@@ -375,7 +376,7 @@ namespace Avalonia.Skia
             {
                 if (boxShadow != default && !boxShadow.IsInset)
                 {
-                    using (var shadow = BoxShadowFilter.Create(_boxShadowPaint, boxShadow, _useOpacitySaveLayer ? 1 : _currentOpacity))
+                    using (var shadow = BoxShadowFilter.Create(_boxShadowPaint, boxShadow, _currentOpacity))
                     {
                         var spread = (float)boxShadow.Spread;
                         if (boxShadow.IsInset)
@@ -432,7 +433,7 @@ namespace Avalonia.Skia
             {
                 if (boxShadow != default && boxShadow.IsInset)
                 {
-                    using (var shadow = BoxShadowFilter.Create(_boxShadowPaint, boxShadow, _useOpacitySaveLayer ? 1 : _currentOpacity))
+                    using (var shadow = BoxShadowFilter.Create(_boxShadowPaint, boxShadow, currentOpacity))
                     {
                         var spread = (float)boxShadow.Spread;
                         var offsetX = (float)boxShadow.OffsetX;
@@ -592,8 +593,16 @@ namespace Avalonia.Skia
         {
             CheckLease();
 
-            if(_useOpacitySaveLayer)
+            _opacityStack.Push(_currentOpacity);
+
+            var useOpacitySaveLayer = _useOpacitySaveLayer || RenderOptions.RequiresFullOpacityHandling == true;
+
+            if (useOpacitySaveLayer)
             {
+                opacity = _currentOpacity * opacity; //Take current multiplied opacity
+
+                _currentOpacity = 1; //Opacity is applied via layering
+
                 if (bounds.HasValue)
                 {
                     var rect = bounds.Value.ToSKRect();
@@ -606,7 +615,6 @@ namespace Avalonia.Skia
             }
             else
             {
-                _opacityStack.Push(_currentOpacity);
                 _currentOpacity *= opacity;
             }
         }
@@ -616,14 +624,14 @@ namespace Avalonia.Skia
         {
             CheckLease();
 
-            if(_useOpacitySaveLayer)
+            var useOpacitySaveLayer = _useOpacitySaveLayer || RenderOptions.RequiresFullOpacityHandling == true;
+
+            if (useOpacitySaveLayer)
             {
                 Canvas.Restore();
             }
-            else
+
-            {
+            _currentOpacity = _opacityStack.Pop();
-                _currentOpacity = _opacityStack.Pop();
-            }    
         }
 
         /// <inheritdoc />