WIP

src/Avalonia.Controls/Primitives/AdornerLayer.cs

@@ -55,12 +55,13 @@ namespace Avalonia.Controls.Primitives
 
             foreach (var child in Children)
             {
-                var info = (AdornedElementInfo)child.GetValue(s_adornedElementInfoProperty);
+                var info = child.GetValue(s_adornedElementInfoProperty);
 
                 if (info != null && info.Bounds.HasValue)
                 {
                     child.RenderTransform = new MatrixTransform(info.Bounds.Value.Transform);
                     child.RenderTransformOrigin = new RelativePoint(new Point(0,0), RelativeUnit.Absolute);
+                    UpdateClip(child, info.Bounds.Value);
                     child.Arrange(info.Bounds.Value.Bounds);
                 }
                 else
@@ -80,6 +81,19 @@ namespace Avalonia.Controls.Primitives
             layer?.UpdateAdornedElement(adorner, adorned);
         }
 
+        private void UpdateClip(IControl control, TransformedBounds bounds)
+        {
+            var clip = control.Clip as RectangleGeometry;
+
+            if (clip == null)
+            {
+                clip = new RectangleGeometry { Transform = new MatrixTransform() };
+                control.Clip = clip;
+            }
+
+            clip.Rect = bounds.Clip.TransformToAABB(-bounds.Transform);
+        }
+
         private void ChildrenCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
         {
             switch (e.Action)

src/Avalonia.Themes.Default/FocusAdorner.xaml

@@ -1,7 +1,7 @@
 <Style xmlns="https://github.com/avaloniaui" Selector=":is(Control)">
   <Setter Property="FocusAdorner">
     <FocusAdornerTemplate>
-      <Rectangle Stroke="Black"
+      <Rectangle Stroke="Black" Name="abcd"
                  StrokeThickness="1"
                  StrokeDashArray="1,2"/>
     </FocusAdornerTemplate>

src/Avalonia.Visuals/Rendering/DeferredRenderer.cs

@@ -243,6 +243,15 @@ namespace Avalonia.Rendering
             {
                 clipBounds = node.ClipBounds.Intersect(clipBounds);
 
+                var np = node.Visual.GetType().GetProperty("Name");
+                var name = (string)np.GetValue(node.Visual);
+
+                if (name == "abcd")
+                {
+                    var clip = (IStreamGeometryImpl)node.GeometryClip;
+                    System.Diagnostics.Debug.WriteLine(clip?.GetRenderBounds(new Pen(Brushes.Black, 1)).ToString() ?? "(null)");
+                }
+
                 if (!clipBounds.IsEmpty && node.Opacity > 0)
                 {
                     var isLayerRoot = node.Visual == layer;

src/Avalonia.Visuals/VisualTree/TransformedBounds.cs

@@ -24,17 +24,17 @@ namespace Avalonia.VisualTree
         }
 
         /// <summary>
-        /// Gets the control's bounds.
+        /// Gets the control's bounds in its local coordinate space.
         /// </summary>
         public Rect Bounds { get; }
 
         /// <summary>
-        /// Gets the control's clip rectangle.
+        /// Gets the control's clip rectangle in global coordinate space.
         /// </summary>
         public Rect Clip { get; }
 
         /// <summary>
-        /// Gets the control's transform.
+        /// Gets the transform from local to global coordinate space.
         /// </summary>
         public Matrix Transform { get; }