Draw selected TextBox text white.

Cairo/Perspex.Cairo/Media/FormattedTextImpl.cs

@@ -98,5 +98,10 @@ namespace Perspex.Cairo.Media
             this.Layout.GetPixelSize(out width, out height);
             return new Size(width, height);
         }
+
+        public void SetForegroundBrush(Brush brush, int startIndex, int count)
+        {
+            // TODO: Implement.
+        }
     }
 }

Perspex.Controls/TextBlock.cs

@@ -43,13 +43,7 @@ namespace Perspex.Controls
                 this.GetObservable(FontStyleProperty).Select(_ => Unit.Default))
                 .Subscribe(_ =>
                 {
-                    if (this.formattedText != null)
-                    {
-                        this.formattedText.Dispose();
-                        this.formattedText = null;
-                    }
-
-                    this.InvalidateMeasure();
+                    this.InvalidateFormattedText();
                 });
         }
 
@@ -89,18 +83,13 @@ namespace Perspex.Controls
             {
                 if (this.formattedText == null)
                 {
-                    this.formattedText = new FormattedText(
-                        this.Text, 
-                        this.FontFamily, 
-                        this.FontSize, 
-                        this.FontStyle);
+                    this.formattedText = this.CreateFormattedText();
                 }
 
                 return this.formattedText;
             }
         }
 
-
         public override void Render(IDrawingContext context)
         {
             Brush background = this.Background;
@@ -113,6 +102,26 @@ namespace Perspex.Controls
             context.DrawText(this.Foreground,  new Point(), this.FormattedText);
         }
 
+        protected virtual FormattedText CreateFormattedText()
+        {
+            return new FormattedText(
+                this.Text,
+                this.FontFamily,
+                this.FontSize,
+                this.FontStyle);
+        }
+
+        protected void InvalidateFormattedText()
+        {
+            if (this.formattedText != null)
+            {
+                this.formattedText.Dispose();
+                this.formattedText = null;
+            }
+
+            this.InvalidateMeasure();
+        }
+
         protected override Size MeasureOverride(Size availableSize)
         {
             if (!string.IsNullOrEmpty(this.Text))

Perspex.Controls/TextBoxView.cs

@@ -31,7 +31,7 @@ namespace Perspex.Controls
             Observable.Merge(
                 this.parent.GetObservable(TextBox.SelectionStartProperty),
                 this.parent.GetObservable(TextBox.SelectionEndProperty))
-                .Subscribe(_ => this.InvalidateVisual());
+                .Subscribe(_ => this.InvalidateFormattedText());
 
             parent.GetObservable(TextBox.CaretIndexProperty).Subscribe(_ => this.CaretMoved());
         }
@@ -95,6 +95,21 @@ namespace Perspex.Controls
             }
         }
 
+        protected override FormattedText CreateFormattedText()
+        {
+            var result = base.CreateFormattedText();
+            var selectionStart = this.parent.SelectionStart;
+            var selectionEnd = this.parent.SelectionEnd;
+            var start = Math.Min(selectionStart, selectionEnd);
+            var length = Math.Max(selectionStart, selectionEnd) - start;
+
+            if (length > 0)
+            {
+                result.SetForegroundBrush(Brushes.White, start, length);
+            }
+            return result;
+        }
+
         internal void CaretMoved()
         {
             this.caretBlink = true;

Perspex.SceneGraph/Media/FormattedText.cs

@@ -93,5 +93,10 @@ namespace Perspex.Media
         {
             return this.PlatformImpl.Measure();
         }
+
+        public void SetForegroundBrush(Brush brush, int startIndex, int count)
+        {
+            this.PlatformImpl.SetForegroundBrush(brush, startIndex, count);
+        }
     }
 } 

Perspex.SceneGraph/Platform/IFormattedTextImpl.cs

@@ -23,5 +23,7 @@ namespace Perspex.Platform
         IEnumerable<Rect> HitTestTextRange(int index, int length, Point origin);
 
         Size Measure();
+
+        void SetForegroundBrush(Brush brush, int startIndex, int count);
     }
 }

Windows/Perspex.Direct2D1/Media/BrushWrapper.cs

@@ -0,0 +1,15 @@
+namespace Perspex.Direct2D1.Media
+{
+    using Perspex.Media;
+    using SharpDX;
+
+    internal class BrushWrapper : ComObject
+    {
+        public BrushWrapper(Brush brush)
+        {
+            this.Brush = brush;
+        }
+
+        public Brush Brush { get; private set; }
+    }
+}

Windows/Perspex.Direct2D1/Media/DrawingContext.cs

@@ -8,7 +8,6 @@ namespace Perspex.Direct2D1.Media
 {
     using System;
     using System.Reactive.Disposables;
-    using Perspex.Direct2D1.Media;
     using Perspex.Media;
     using SharpDX;
     using SharpDX.Direct2D1;
@@ -142,12 +141,9 @@ namespace Perspex.Direct2D1.Media
             {
                 var impl = (FormattedTextImpl)text.PlatformImpl;
 
-                using (var brush = foreground.ToDirect2D(this.renderTarget))
+                using (var renderer = new PerspexTextRenderer(this.renderTarget, foreground.ToDirect2D(this.renderTarget)))
                 {
-                    this.renderTarget.DrawTextLayout(
-                        origin.ToSharpDX(),
-                        impl.TextLayout,
-                        brush);
+                    impl.TextLayout.Draw(renderer, (float)origin.X, (float)origin.Y);
                 }
             }
         }

Windows/Perspex.Direct2D1/Media/FormattedTextImpl.cs

@@ -113,5 +113,12 @@ namespace Perspex.Direct2D1.Media
                 this.TextLayout.Metrics.WidthIncludingTrailingWhitespace,
                 this.TextLayout.Metrics.Height);
         }
+
+        public void SetForegroundBrush(Brush brush, int startIndex, int count)
+        {
+            this.TextLayout.SetDrawingEffect(
+                new BrushWrapper(brush),
+                new DWrite.TextRange(startIndex, count));
+        }
     }
 }

Windows/Perspex.Direct2D1/Media/PerspexTextRenderer.cs

@@ -0,0 +1,97 @@
+// -----------------------------------------------------------------------
+// <copyright file="PerspexTextRenderer.cs" company="Steven Kirk">
+// Copyright 2013 MIT Licence. See licence.md for more information.
+// </copyright>
+// -----------------------------------------------------------------------
+
+namespace Perspex.Direct2D1.Media
+{
+    using System;
+    using SharpDX;
+    using SharpDX.Direct2D1;
+    using SharpDX.DirectWrite;
+
+    internal class PerspexTextRenderer : TextRenderer
+    {
+        private RenderTarget renderTarget;
+
+        private Brush foreground;
+
+        public PerspexTextRenderer(
+            RenderTarget target,
+            Brush foreground)
+        {
+            this.renderTarget = target;
+            this.foreground = foreground;
+        }
+
+        public IDisposable Shadow
+        {
+            get;
+            set;
+        }
+
+        public void Dispose()
+        {
+            this.foreground.Dispose();
+        }
+
+        public Result DrawGlyphRun(
+            object clientDrawingContext, 
+            float baselineOriginX, 
+            float baselineOriginY, 
+            MeasuringMode measuringMode, 
+            GlyphRun glyphRun, 
+            GlyphRunDescription glyphRunDescription, 
+            ComObject clientDrawingEffect)
+        {
+            var wrapper = clientDrawingEffect as BrushWrapper;
+            var brush = (wrapper == null) ? 
+                this.foreground : 
+                wrapper.Brush.ToDirect2D(this.renderTarget);
+
+            this.renderTarget.DrawGlyphRun(
+                new Vector2(baselineOriginX, baselineOriginY),
+                glyphRun,
+                brush,
+                measuringMode);
+
+            if (wrapper != null)
+            {
+                brush.Dispose();
+            }
+
+            return Result.Ok;
+        }
+
+        public Result DrawInlineObject(object clientDrawingContext, float originX, float originY, InlineObject inlineObject, bool isSideways, bool isRightToLeft, ComObject clientDrawingEffect)
+        {
+            throw new NotImplementedException();
+        }
+
+        public Result DrawStrikethrough(object clientDrawingContext, float baselineOriginX, float baselineOriginY, ref Strikethrough strikethrough, ComObject clientDrawingEffect)
+        {
+            throw new NotImplementedException();
+        }
+
+        public Result DrawUnderline(object clientDrawingContext, float baselineOriginX, float baselineOriginY, ref Underline underline, ComObject clientDrawingEffect)
+        {
+            throw new NotImplementedException();
+        }
+
+        public Matrix3x2 GetCurrentTransform(object clientDrawingContext)
+        {
+            return this.renderTarget.Transform;
+        }
+
+        public float GetPixelsPerDip(object clientDrawingContext)
+        {
+            return this.renderTarget.DotsPerInch.Width / 96;
+        }
+
+        public bool IsPixelSnappingDisabled(object clientDrawingContext)
+        {
+            return false;
+        }
+    }
+}

Windows/Perspex.Direct2D1/Perspex.Direct2D1.csproj

@@ -67,9 +67,11 @@
   </ItemGroup>
   <ItemGroup>
     <Compile Include="Direct2D1Platform.cs" />
+    <Compile Include="Media\BrushWrapper.cs" />
     <Compile Include="Media\DrawingContext.cs" />
     <Compile Include="Media\Imaging\RenderTargetBitmapImpl.cs" />
     <Compile Include="Media\Imaging\BitmapImpl.cs" />
+    <Compile Include="Media\PerspexTextRenderer.cs" />
     <Compile Include="Media\StreamGeometryContextImpl.cs" />
     <Compile Include="Media\GeometryImpl.cs" />
     <Compile Include="Media\StreamGeometryImpl.cs" />