Merge pull request #6900 from AvaloniaUI/fixes/6899-rtb-transformedbounds

Don't update TransformedBounds from RenderTargetBitmap.

src/Avalonia.Visuals/Rendering/ImmediateRenderer.cs

@@ -20,6 +20,7 @@ namespace Avalonia.Rendering
     {
         private readonly IVisual _root;
         private readonly IRenderRoot _renderRoot;
+        private bool _updateTransformedBounds = true;
         private IRenderTarget _renderTarget;
 
         /// <summary>
@@ -34,6 +35,13 @@ namespace Avalonia.Rendering
             _renderRoot = root as IRenderRoot;
         }
 
+        private ImmediateRenderer(IVisual root, bool updateTransformedBounds)
+        {
+            _root = root ?? throw new ArgumentNullException(nameof(root));
+            _renderRoot = root as IRenderRoot;
+            _updateTransformedBounds = updateTransformedBounds;
+        }
+
         /// <inheritdoc/>
         public bool DrawFps { get; set; }
 
@@ -98,7 +106,7 @@ namespace Avalonia.Rendering
         /// <param name="target">The render target.</param>
         public static void Render(IVisual visual, IRenderTarget target)
         {
-            using (var renderer = new ImmediateRenderer(visual))
+            using (var renderer = new ImmediateRenderer(visual, updateTransformedBounds: false))
             using (var context = new DrawingContext(target.CreateDrawingContext(renderer)))
             {
                 renderer.Render(context, visual, visual.Bounds);
@@ -112,7 +120,7 @@ namespace Avalonia.Rendering
         /// <param name="context">The drawing context.</param>
         public static void Render(IVisual visual, DrawingContext context)
         {
-            using (var renderer = new ImmediateRenderer(visual))
+            using (var renderer = new ImmediateRenderer(visual, updateTransformedBounds: false))
             {
                 renderer.Render(context, visual, visual.Bounds);
             }
@@ -193,6 +201,12 @@ namespace Avalonia.Rendering
             Render(new DrawingContext(context), visual, visual.Bounds);
         }
 
+        internal static void Render(IVisual visual, DrawingContext context, bool updateTransformedBounds)
+        {
+            using var renderer = new ImmediateRenderer(visual, updateTransformedBounds);
+            renderer.Render(context, visual, visual.Bounds);
+        }
+
         private static void ClearTransformedBounds(IVisual visual)
         {
             foreach (var e in visual.GetSelfAndVisualDescendants())
@@ -305,7 +319,8 @@ namespace Avalonia.Rendering
                         new TransformedBounds(bounds, new Rect(), context.CurrentContainerTransform);
 #pragma warning restore 0618
 
-                    visual.TransformedBounds = transformed;
+                    if (_updateTransformedBounds)
+                        visual.TransformedBounds = transformed;
 
                     foreach (var child in visual.VisualChildren.OrderBy(x => x, ZIndexComparer.Instance))
                     {
@@ -318,7 +333,7 @@ namespace Avalonia.Rendering
                                 : clipRect;
                             Render(context, child, childClipRect);
                         }
-                        else
+                        else if (_updateTransformedBounds)
                         {
                             ClearTransformedBounds(child);
                         }
@@ -326,7 +341,7 @@ namespace Avalonia.Rendering
                 }
             }
 
-            if (!visual.IsVisible)
+            if (!visual.IsVisible && _updateTransformedBounds)
             {
                 ClearTransformedBounds(visual);
             }

tests/Avalonia.Visuals.UnitTests/Rendering/ImmediateRendererTests.cs

@@ -291,6 +291,24 @@ namespace Avalonia.Visuals.UnitTests.Rendering
             }
         }
 
+        [Fact]
+        public void Static_Render_Method_Does_Not_Update_TransformedBounds()
+        {
+            using (UnitTestApplication.Start(TestServices.MockPlatformRenderInterface))
+            {
+                var target = new Border();
+                var expected = new TransformedBounds(new Rect(1, 2, 3, 4), new Rect(4, 5, 6, 7), Matrix.CreateRotation(0.8));
+
+                ((IVisual)target).TransformedBounds = expected;
+
+                var renderTarget = Mock.Of<IRenderTarget>(x => 
+                    x.CreateDrawingContext(It.IsAny<IVisualBrushRenderer>()) == Mock.Of<IDrawingContextImpl>());
+                ImmediateRenderer.Render(target, renderTarget);
+
+                Assert.Equal(expected, target.TransformedBounds);
+            }
+        }
+
         private class TestControl : Control
         {
             public bool Rendered { get; private set; }

tests/Avalonia.Visuals.UnitTests/VisualTree/TransformedBoundsTests.cs

@@ -40,7 +40,7 @@ namespace Avalonia.Visuals.UnitTests.VisualTree
 
                 tree.Measure(Size.Infinity);
                 tree.Arrange(new Rect(0, 0, 100, 100));
-                ImmediateRenderer.Render(tree, context);
+                ImmediateRenderer.Render(tree, context, true);
 
                 var track = control.GetObservable(Visual.TransformedBoundsProperty);
                 var results = new List<TransformedBounds?>();