Implemented VisualBrush on cairo.

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

@@ -217,6 +217,7 @@ namespace Perspex.Cairo.Media
             var solid = brush as SolidColorBrush;
             var linearGradientBrush = brush as LinearGradientBrush;
             var imageBrush = brush as ImageBrush;
+            var visualBrush = brush as VisualBrush;
 
             if (solid != null)
             {
@@ -226,10 +227,6 @@ namespace Perspex.Cairo.Media
                     solid.Color.B / 255.0,
                     solid.Color.A / 255.0);
             }
-            else if (imageBrush != null)
-            {
-                _context.SetSource(TileBrushes.CreateImageBrush(imageBrush, destinationSize));
-            }
             else if (linearGradientBrush != null)
             {
                 var start = linearGradientBrush.StartPoint.ToPixels(destinationSize);
@@ -244,6 +241,14 @@ namespace Perspex.Cairo.Media
                 
                 _context.SetSource(g);
             }
+            else if (imageBrush != null)
+            {
+                _context.SetSource(TileBrushes.CreateImageBrush(imageBrush, destinationSize));
+            }
+            else if (visualBrush != null)
+            {
+                _context.SetSource(TileBrushes.CreateVisualBrush(visualBrush, destinationSize));
+            }
         }
 
         private void SetPen(Pen pen, Size destinationSize)

src/Gtk/Perspex.Cairo/Media/TileBrushes.cs

@@ -1,9 +1,12 @@
 // Copyright (c) The Perspex Project. All rights reserved.
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
+using System;
 using Cairo;
 using Perspex.Cairo.Media.Imaging;
+using Perspex.Layout;
 using Perspex.Media;
+using Perspex.Platform;
 
 namespace Perspex.Cairo.Media
 {
@@ -70,6 +73,75 @@ namespace Perspex.Cairo.Media
             }
         }
 
+        public static SurfacePattern CreateVisualBrush(VisualBrush brush, Size targetSize)
+        {
+            var visual = brush.Visual;
+
+            if (visual == null)
+            {
+                return null;
+            }
+
+            var layoutable = visual as ILayoutable;
+
+            if (layoutable?.IsArrangeValid == false)
+            {
+                layoutable.Measure(Size.Infinity);
+                layoutable.Arrange(new Rect(layoutable.DesiredSize));
+            }
+
+            // TODO: This is directly ported from Direct2D and could probably be made more
+            // efficient on cairo by taking advantage of the fact that cairo has Extend.None.
+            var tileMode = brush.TileMode;
+            var sourceRect = brush.SourceRect.ToPixels(layoutable.Bounds.Size);
+            var destinationRect = brush.DestinationRect.ToPixels(targetSize);
+            var scale = brush.Stretch.CalculateScaling(destinationRect.Size, sourceRect.Size);
+            var translate = CalculateTranslate(brush, sourceRect, destinationRect, scale);
+            var intermediateSize = CalculateIntermediateSize(tileMode, targetSize, destinationRect.Size);
+            var intermediate = new ImageSurface(Format.ARGB32, (int)intermediateSize.Width, (int)intermediateSize.Height);
+
+            using (var context = new Context(intermediate))
+            {
+                Rect drawRect;
+                var transform = CalculateIntermediateTransform(
+                    tileMode,
+                    sourceRect,
+                    destinationRect,
+                    scale,
+                    translate,
+                    out drawRect);
+                var renderer = new Renderer(intermediate);
+
+                context.Rectangle(drawRect.ToCairo());
+                context.Clip();
+                context.Transform(transform.ToCairo());
+                renderer.Render(visual, new PlatformHandle(IntPtr.Zero, "RTB"), transform, drawRect);
+
+                var result = new SurfacePattern(intermediate);
+
+                if ((brush.TileMode & TileMode.FlipXY) != 0)
+                {
+                    // TODO: Currently always FlipXY as that's all cairo supports natively. 
+                    // Support separate FlipX and FlipY by drawing flipped images to intermediate
+                    // surface.
+                    result.Extend = Extend.Reflect;
+                }
+                else
+                {
+                    result.Extend = Extend.Repeat;
+                }
+
+                if (brush.TileMode != TileMode.None)
+                {
+                    var matrix = result.Matrix;
+                    matrix.InitTranslate(-destinationRect.X, -destinationRect.Y);
+                    result.Matrix = matrix;
+                }
+
+                return result;
+            }
+        }
+
         /// <summary>
         /// Calculates a translate based on a <see cref="TileBrush"/>, a source and destination
         /// rectangle and a scale.

src/Gtk/Perspex.Cairo/Perspex.Cairo.csproj

@@ -88,6 +88,10 @@
       <Project>{B09B78D8-9B26-48B0-9149-D64A2F120F3F}</Project>
       <Name>Perspex.Base</Name>
     </ProjectReference>
+    <ProjectReference Include="..\..\Perspex.Layout\Perspex.Layout.csproj">
+      <Project>{42472427-4774-4c81-8aff-9f27b8e31721}</Project>
+      <Name>Perspex.Layout</Name>
+    </ProjectReference>
     <ProjectReference Include="..\..\Perspex.SceneGraph\Perspex.SceneGraph.csproj">
       <Project>{EB582467-6ABB-43A1-B052-E981BA910E3A}</Project>
       <Name>Perspex.SceneGraph</Name>

tests/Perspex.RenderTests/Media/VisualBrushTests.cs

@@ -58,11 +58,7 @@ namespace Perspex.Direct2D1.RenderTests.Media
             }
         }
 
-#if PERSPEX_CAIRO
-        [Fact(Skip = "VisualBrush not yet implemented on Cairo")]
-#else
         [Fact]
-#endif
         public void VisualBrush_NoStretch_NoTile_Alignment_TopLeft()
         {
             Decorator target = new Decorator
@@ -87,11 +83,7 @@ namespace Perspex.Direct2D1.RenderTests.Media
             CompareImages();
         }
 
-#if PERSPEX_CAIRO
-        [Fact(Skip = "VisualBrush not yet implemented on Cairo")]
-#else
         [Fact]
-#endif
         public void VisualBrush_NoStretch_NoTile_Alignment_Center()
         {
             Decorator target = new Decorator
@@ -116,11 +108,7 @@ namespace Perspex.Direct2D1.RenderTests.Media
             CompareImages();
         }
 
-#if PERSPEX_CAIRO
-        [Fact(Skip = "VisualBrush not yet implemented on Cairo")]
-#else
         [Fact]
-#endif
         public void VisualBrush_NoStretch_NoTile_Alignment_BottomRight()
         {
             Decorator target = new Decorator
@@ -145,11 +133,7 @@ namespace Perspex.Direct2D1.RenderTests.Media
             CompareImages();
         }
 
-#if PERSPEX_CAIRO
-        [Fact(Skip = "VisualBrush not yet implemented on Cairo")]
-#else
         [Fact]
-#endif
         public void VisualBrush_Fill_NoTile()
         {
             Decorator target = new Decorator
@@ -172,11 +156,7 @@ namespace Perspex.Direct2D1.RenderTests.Media
             CompareImages();
         }
 
-#if PERSPEX_CAIRO
-        [Fact(Skip = "VisualBrush not yet implemented on Cairo")]
-#else
         [Fact]
-#endif
         public void VisualBrush_Uniform_NoTile()
         {
             Decorator target = new Decorator
@@ -199,11 +179,7 @@ namespace Perspex.Direct2D1.RenderTests.Media
             CompareImages();
         }
 
-#if PERSPEX_CAIRO
-        [Fact(Skip = "VisualBrush not yet implemented on Cairo")]
-#else
         [Fact]
-#endif
         public void VisualBrush_UniformToFill_NoTile()
         {
             Decorator target = new Decorator
@@ -226,11 +202,7 @@ namespace Perspex.Direct2D1.RenderTests.Media
             CompareImages();
         }
 
-#if PERSPEX_CAIRO
-        [Fact(Skip = "VisualBrush not yet implemented on Cairo")]
-#else
         [Fact]
-#endif
         public void VisualBrush_NoStretch_NoTile_BottomRightQuarterSource()
         {
             Decorator target = new Decorator
@@ -254,11 +226,7 @@ namespace Perspex.Direct2D1.RenderTests.Media
             CompareImages();
         }
 
-#if PERSPEX_CAIRO
-        [Fact(Skip = "VisualBrush not yet implemented on Cairo")]
-#else
         [Fact]
-#endif
         public void VisualBrush_NoStretch_NoTile_BottomRightQuarterDest()
         {
             Decorator target = new Decorator
@@ -282,11 +250,7 @@ namespace Perspex.Direct2D1.RenderTests.Media
             CompareImages();
         }
 
-#if PERSPEX_CAIRO
-        [Fact(Skip = "VisualBrush not yet implemented on Cairo")]
-#else
         [Fact]
-#endif
         public void VisualBrush_NoStretch_NoTile_BottomRightQuarterSource_BottomRightQuarterDest()
         {
             Decorator target = new Decorator
@@ -311,11 +275,7 @@ namespace Perspex.Direct2D1.RenderTests.Media
             CompareImages();
         }
 
-#if PERSPEX_CAIRO
-        [Fact(Skip = "VisualBrush not yet implemented on Cairo")]
-#else
         [Fact]
-#endif
         public void VisualBrush_NoStretch_Tile_BottomRightQuarterSource_CenterQuarterDest()
         {
             Decorator target = new Decorator
@@ -341,7 +301,7 @@ namespace Perspex.Direct2D1.RenderTests.Media
         }
 
 #if PERSPEX_CAIRO
-        [Fact(Skip = "VisualBrush not yet implemented on Cairo")]
+        [Fact(Skip = "TileMode.FlipX not yet supported on cairo")]
 #else
         [Fact]
 #endif
@@ -369,7 +329,7 @@ namespace Perspex.Direct2D1.RenderTests.Media
         }
 
 #if PERSPEX_CAIRO
-        [Fact(Skip = "VisualBrush not yet implemented on Cairo")]
+        [Fact(Skip = "TileMode.FlipY not yet supported on cairo")]
 #else
         [Fact]
 #endif
@@ -396,11 +356,7 @@ namespace Perspex.Direct2D1.RenderTests.Media
             CompareImages();
         }
 
-#if PERSPEX_CAIRO
-        [Fact(Skip = "VisualBrush not yet implemented on Cairo")]
-#else
         [Fact]
-#endif
         public void VisualBrush_NoStretch_FlipXY_TopLeftDest()
         {
             Decorator target = new Decorator