Merge pull request #544 from jkoritzinsky/Path-Clipping

Add support for clipping to a Geometry. Fixes #359.

src/Avalonia.SceneGraph/Media/DrawingContext.cs

@@ -127,7 +127,8 @@ namespace Avalonia.Media
                 Matrix,
                 Opacity,
                 Clip,
-                MatrixContainer
+                MatrixContainer,
+                GeometryClip
             }
 
             public PushedState(DrawingContext context, PushedStateType type, Matrix matrix = default(Matrix))
@@ -149,10 +150,12 @@ namespace Avalonia.Media
                 _context._states.Pop();
                 if (_type == PushedStateType.Matrix)
                     _context.CurrentTransform = _matrix;
-                else if(_type == PushedStateType.Clip)
+                else if (_type == PushedStateType.Clip)
                     _context._impl.PopClip();
-                else if(_type == PushedStateType.Opacity)
+                else if (_type == PushedStateType.Opacity)
                     _context._impl.PopOpacity();
+                else if (_type == PushedStateType.GeometryClip)
+                    _context._impl.PopGeometryClip();
                 else if (_type == PushedStateType.MatrixContainer)
                 {
                     var cont = _context._transformContainers.Pop();
@@ -174,6 +177,18 @@ namespace Avalonia.Media
             return new PushedState(this, PushedState.PushedStateType.Clip);
         }
 
+        /// <summary>
+        /// Pushes a clip geometry.
+        /// </summary>
+        /// <param name="clip">The clip geometry.</param>
+        /// <returns>A disposable used to undo the clip geometry.</returns>
+        public PushedState PushGeometryClip(Geometry clip)
+        {
+            Contract.Requires<ArgumentNullException>(clip != null);
+            _impl.PushGeometryClip(clip);
+            return new PushedState(this, PushedState.PushedStateType.GeometryClip);
+        }
+
         /// <summary>
         /// Pushes an opacity value.
         /// </summary>

src/Avalonia.SceneGraph/Media/IDrawingContext.cs

@@ -69,7 +69,6 @@ namespace Avalonia.Media
         /// Pushes a clip rectange.
         /// </summary>
         /// <param name="clip">The clip rectangle.</param>
-        /// <returns>A disposable used to undo the clip rectangle.</returns>
         void PushClip(Rect clip);
 
         void PopClip();
@@ -78,9 +77,16 @@ namespace Avalonia.Media
         /// Pushes an opacity value.
         /// </summary>
         /// <param name="opacity">The opacity.</param>
-        /// <returns>A disposable used to undo the opacity.</returns>
         void PushOpacity(double opacity);
 
         void PopOpacity();
+
+        /// <summary>
+        /// Pushes a clip geometry.
+        /// </summary>
+        /// <param name="clip">The clip geometry.</param>
+        void PushGeometryClip(Geometry clip);
+
+        void PopGeometryClip();
     }
 }

src/Avalonia.SceneGraph/Media/PathMarkupParser.cs

@@ -34,6 +34,12 @@ namespace Avalonia.Media
             { 'z', Command.Close },
         };
 
+        private static readonly Dictionary<char, FillRule> FillRules = new Dictionary<char, FillRule>
+        {
+            {'0', FillRule.EvenOdd },
+            {'1', FillRule.NonZero }
+        };
+
         private StreamGeometry _geometry;
 
         private readonly StreamGeometryContext _context;
@@ -90,8 +96,7 @@ namespace Avalonia.Media
                     switch (command)
                     {
                         case Command.FillRule:
-                            // TODO: Implement.
-                            reader.Read();
+                            _context.SetFillRule(ReadFillRule(reader));
                             break;
 
                         case Command.Move:
@@ -226,6 +231,24 @@ namespace Avalonia.Media
             }
         }
 
+        private static FillRule ReadFillRule(StringReader reader)
+        {
+            int i = reader.Read();
+            if (i == -1)
+            {
+                throw new InvalidDataException("Invalid fill rule");
+            }
+            char c = (char)i;
+            FillRule rule;
+
+            if (!FillRules.TryGetValue(c, out rule))
+            {
+                throw new InvalidDataException("Invalid fill rule");
+            }
+
+            return rule;
+        }
+
         private static double ReadDouble(StringReader reader)
         {
             ReadWhitespace(reader);

src/Avalonia.SceneGraph/Rendering/RendererMixin.cs

@@ -119,6 +119,7 @@ namespace Avalonia.Rendering
                 using (context.PushPostTransform(m))
                 using (context.PushOpacity(opacity))
                 using (clipToBounds ? context.PushClip(bounds) : default(DrawingContext.PushedState))
+                using (visual.Clip != null ? context.PushGeometryClip(visual.Clip) : default(DrawingContext.PushedState))
                 using (context.PushTransformContainer())
                 {
                     visual.Render(context);

src/Avalonia.SceneGraph/Visual.cs

@@ -39,6 +39,12 @@ namespace Avalonia
         public static readonly StyledProperty<bool> ClipToBoundsProperty =
             AvaloniaProperty.Register<Visual, bool>(nameof(ClipToBounds));
 
+        /// <summary>
+        /// Defines the <see cref="Clip"/> property.
+        /// </summary>
+        public static readonly StyledProperty<Geometry> ClipProperty =
+            AvaloniaProperty.Register<Visual, Geometry>(nameof(Clip));
+
         /// <summary>
         /// Defines the <see cref="IsVisibleProperty"/> property.
         /// </summary>
@@ -127,6 +133,15 @@ namespace Avalonia
             set { SetValue(ClipToBoundsProperty, value); }
         }
 
+        /// <summary>
+        /// Gets or sets the geometry clip for this visual.
+        /// </summary>
+        public Geometry Clip
+        {
+            get { return GetValue(ClipProperty); }
+            set { SetValue(ClipProperty, value); }
+        }
+
         /// <summary>
         /// Gets a value indicating whether this scene graph node and all its parents are visible.
         /// </summary>

src/Avalonia.SceneGraph/VisualTree/IVisual.cs

@@ -41,6 +41,11 @@ namespace Avalonia.VisualTree
         /// </summary>
         bool ClipToBounds { get; set; }
 
+        /// <summary>
+        /// Gets or sets the geometry clip for this visual.
+        /// </summary>
+        Geometry Clip { get; set; }
+
         /// <summary>
         /// Gets a value indicating whether this scene graph node is attached to a visual root.
         /// </summary>

src/Gtk/Avalonia.Cairo/Media/DrawingContext.cs

@@ -340,5 +340,17 @@ namespace Avalonia.Cairo.Media
 			
 			return SetBrush(pen.Brush, destinationSize);
         }
+
+        public void PushGeometryClip(Geometry clip)
+        {
+            _context.Save();
+            _context.AppendPath(((StreamGeometryImpl)clip.PlatformImpl).Path);
+            _context.Clip();
+        }
+
+        public void PopGeometryClip()
+        {
+            _context.Restore();
+        }
     }
 }

src/Gtk/Avalonia.Cairo/Media/StreamGeometryContextImpl.cs

@@ -64,7 +64,11 @@ namespace Avalonia.Cairo.Media
 
         internal bool FillContains(Point point)
         {
-            return _context.InFill(point.X, point.Y);
+            using (var context = new Cairo.Context(new Cairo.ImageSurface(Cairo.Format.Argb32, 0, 0)))
+            {
+                context.AppendPath(Path);
+                return context.InFill(point.X, point.Y); 
+            }
         }
 
         public void LineTo(Point point)

src/Skia/Avalonia.Skia/DrawingContextImpl.cs

@@ -288,6 +288,17 @@ namespace Avalonia.Skia
         {
         }
 
+        public void PushGeometryClip(Geometry clip)
+        {
+            Canvas.Save();
+            Canvas.ClipPath(((StreamGeometryImpl)clip.PlatformImpl).EffectivePath);
+        }
+
+        public void PopGeometryClip()
+        {
+            Canvas.Restore();
+        }
+
         private Matrix _currentTransform = Matrix.Identity;
 
         public Matrix Transform

src/Windows/Avalonia.Direct2D1/Media/DrawingContext.cs

@@ -276,6 +276,11 @@ namespace Avalonia.Direct2D1.Media
         }
 
         public void PopOpacity()
+        {
+            PopLayer();
+        }
+
+        private void PopLayer()
         {
             var layer = _layers.Pop();
             if (layer != null)
@@ -324,5 +329,26 @@ namespace Avalonia.Direct2D1.Media
                 return new SolidColorBrushImpl((Avalonia.Media.SolidColorBrush)null, _renderTarget);
             }
         }
+
+        public void PushGeometryClip(Avalonia.Media.Geometry clip)
+        {
+            var parameters = new LayerParameters
+            {
+                ContentBounds = PrimitiveExtensions.RectangleInfinite,
+                MaskTransform = PrimitiveExtensions.Matrix3x2Identity,
+                Opacity = 1,
+                GeometricMask = ((GeometryImpl)clip.PlatformImpl).Geometry
+            };
+            var layer = _layerPool.Count != 0 ? _layerPool.Pop() : new Layer(_renderTarget);
+            _renderTarget.PushLayer(ref parameters, layer);
+
+            _layers.Push(layer);
+
+        }
+
+        public void PopGeometryClip()
+        {
+            PopLayer();
+        }
     }
 }

tests/Avalonia.RenderTests/Avalonia.RenderTests.projitems

@@ -8,7 +8,7 @@
   <PropertyGroup Label="Configuration">
     <Import_RootNamespace>Avalonia.RenderTests</Import_RootNamespace>
   </PropertyGroup>
-<ItemGroup>
+  <ItemGroup>
     <Compile Include="Controls\ImageTests.cs" />
     <Compile Include="Controls\BorderTests.cs" />
     <Compile Include="Media\ImageBrushTests.cs" />
@@ -22,5 +22,6 @@
     <Compile Include="Shapes\RectangleTests.cs" />
     <Compile Include="TestBase.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="GeometryClippingTests.cs" />
   </ItemGroup>
-</Project>
+</Project>

tests/Avalonia.RenderTests/GeometryClippingTests.cs

@@ -0,0 +1,51 @@
+using Avalonia.Controls;
+using Avalonia.Controls.Shapes;
+using Avalonia.Media;
+using System;
+using System.Collections.Generic;
+using System.Text;
+using Xunit;
+
+#if AVALONIA_CAIRO
+namespace Avalonia.Cairo.RenderTests
+#elif AVALONIA_SKIA
+namespace Avalonia.Skia.RenderTests
+#else
+namespace Avalonia.Direct2D1.RenderTests
+#endif
+{
+    public class GeometryClippingTests : TestBase
+    {
+        public GeometryClippingTests()
+            :base("GeometryClipping")
+        {
+        }
+
+        [Fact]
+        public void Geometry_Clip_Clips_Path()
+        {
+            var target = new Canvas
+            {
+                Clip = StreamGeometry.Parse("F1 M 0,0  H 76 V 76 Z"),
+                Width = 76,
+                Height = 76,
+                Children = new Avalonia.Controls.Controls
+                {
+                    new Path
+                    {
+                        Width = 32,
+                        Height = 40,
+                        [Canvas.LeftProperty] = 23,
+                        [Canvas.TopProperty] = 18,
+                        Stretch = Stretch.Fill,
+                        Fill = Brushes.Black,
+                        Data = StreamGeometry.Parse("F1 M 27,18L 23,26L 33,30L 24,38L 33,46L 23,50L 27,58L 45,58L 55,38L 45,18L 27,18 Z")
+                    }
+                }
+            };
+
+            RenderToFile(target);
+            CompareImages();
+        }
+    }
+}