Started refactoring of FormattedText.

Perspex.Controls/TextBlock.cs

@@ -25,9 +25,27 @@ namespace Perspex.Controls
         public static readonly PerspexProperty<string> TextProperty =
             PerspexProperty.Register<TextBlock, string>("Text");
 
-        static TextBlock()
+        private FormattedText formattedText = new FormattedText();
+
+        public TextBlock()
         {
-            Control.AffectsMeasure(TextProperty);
+            this.GetObservable(TextProperty).Subscribe(x =>
+            {
+                this.formattedText.Text = x;
+                this.InvalidateMeasure();
+            });
+
+            this.GetObservable(FontSizeProperty).Subscribe(x =>
+            {
+                this.formattedText.FontSize = x;
+                this.InvalidateMeasure();
+            });
+
+            this.GetObservable(FontStyleProperty).Subscribe(x =>
+            {
+                this.formattedText.FontStyle = x;
+                this.InvalidateMeasure();
+            });
         }
 
         public string Text
@@ -48,20 +66,6 @@ namespace Perspex.Controls
             set { this.SetValue(FontStyleProperty, value); }
         }
 
-        private FormattedText FormattedText
-        {
-            get
-            {
-                return new FormattedText
-                {
-                    FontFamilyName = "Segoe UI",
-                    FontSize = this.FontSize,
-                    FontStyle = this.FontStyle,
-                    Text = this.Text,
-                };
-            }
-        }
-
         public override void Render(IDrawingContext context)
         {
             Brush background = this.Background;
@@ -71,15 +75,18 @@ namespace Perspex.Controls
                 context.FillRectange(background, new Rect(this.ActualSize));
             }
 
-            context.DrawText(this.Foreground, new Rect(this.ActualSize), this.FormattedText);
+            context.DrawText(
+                this.Foreground, 
+                new Rect(this.ActualSize), 
+                this.formattedText);
         }
 
         protected override Size MeasureOverride(Size availableSize)
         {
             if (!string.IsNullOrEmpty(this.Text))
             {
-                ITextService textService = Locator.Current.GetService<ITextService>();
-                return textService.Measure(this.FormattedText, availableSize);
+                this.formattedText.Constraint = availableSize;
+                return this.formattedText.Measure();
             }
 
             return new Size();

Perspex.Controls/TextBox.cs

@@ -95,7 +95,6 @@ namespace Perspex.Controls
             }
 
             textContainer.Content = this.textBoxView = new TextBoxView(this);
-            this.GetObservable(TextProperty).Subscribe(_ => this.textBoxView.InvalidateText());
         }
 
         private void OnKeyDown(object sender, KeyEventArgs e)

Perspex.Controls/TextBoxView.cs

@@ -24,6 +24,29 @@ namespace Perspex.Controls
 
         public TextBoxView(TextBox parent)
         {
+            this.FormattedText = new FormattedText();
+
+            // TODO: Implement TextBlock.FontFamilyName.
+            this.FormattedText.FontFamilyName = "Segoe UI";
+
+            parent.GetObservable(TextBox.TextProperty).Subscribe(x =>
+            {
+                this.FormattedText.Text = x;
+                this.InvalidateMeasure();
+            });
+
+            this.GetObservable(TextBlock.FontSizeProperty).Subscribe(x =>
+            {
+                this.FormattedText.FontSize = x;
+                this.InvalidateMeasure();
+            });
+
+            this.GetObservable(TextBlock.FontStyleProperty).Subscribe(x =>
+            {
+                this.FormattedText.FontStyle = x;
+                this.InvalidateMeasure();
+            });
+
             this.caretTimer = new DispatcherTimer();
             this.caretTimer.Interval = TimeSpan.FromMilliseconds(500);
             this.caretTimer.Tick += this.CaretTimerTick;
@@ -32,15 +55,8 @@ namespace Perspex.Controls
 
         public FormattedText FormattedText
         {
-            get
-            {
-                if (this.formattedText == null)
-                {
-                    this.formattedText = this.CreateFormattedText();
-                }
-
-                return this.formattedText;
-            }
+            get;
+            private set;
         }
 
         public new void GotFocus()
@@ -55,12 +71,6 @@ namespace Perspex.Controls
             this.InvalidateVisual();
         }
 
-        public void InvalidateText()
-        {
-            this.formattedText = null;
-            this.InvalidateMeasure();
-        }
-
         public override void Render(IDrawingContext context)
         {
             Rect rect = new Rect(this.ActualSize);
@@ -69,20 +79,12 @@ namespace Perspex.Controls
 
             if (this.parent.IsFocused)
             {
-                ITextService textService = Locator.Current.GetService<ITextService>();
-                Point caretPos = textService.GetCaretPosition(
-                    this.formattedText, 
-                    this.parent.CaretIndex,
-                    this.ActualSize);
-                double[] lineHeights = textService.GetLineHeights(this.formattedText, this.ActualSize);
+                var charPos = this.FormattedText.HitTestTextPosition(this.parent.CaretIndex);
                 Brush caretBrush = Brushes.Black;
 
                 if (this.caretBlink)
                 {
-                    context.DrawLine(
-                        new Pen(caretBrush, 1),
-                        caretPos,
-                        new Point(caretPos.X, caretPos.Y + lineHeights[0]));
+                    context.DrawLine(new Pen(caretBrush, 1), charPos.TopLeft, charPos.BottomLeft);
                 }
             }
         }
@@ -99,24 +101,13 @@ namespace Perspex.Controls
         {
             if (!string.IsNullOrEmpty(this.parent.Text))
             {
-                ITextService textService = Locator.Current.GetService<ITextService>();
-                return textService.Measure(this.FormattedText, constraint);
+                this.FormattedText.Constraint = constraint;
+                return this.FormattedText.Measure();
             }
 
             return new Size();
         }
 
-        private FormattedText CreateFormattedText()
-        {
-            return new FormattedText
-            {
-                FontFamilyName = "Segoe UI",
-                FontSize = this.GetValue(TextBlock.FontSizeProperty),
-                FontStyle = this.GetValue(TextBlock.FontStyleProperty),
-                Text = this.parent.Text,
-            };
-        }
-
         private void CaretTimerTick(object sender, EventArgs e)
         {
             this.caretBlink = !this.caretBlink;

Perspex.SceneGraph/Media/FormattedText.cs

@@ -6,6 +6,9 @@
 
 namespace Perspex.Media
 {
+    using Perspex.Platform;
+    using Splat;
+
     public enum FontStyle
     {
         Normal,
@@ -15,12 +18,56 @@ namespace Perspex.Media
 
     public class FormattedText
     {
-        public string FontFamilyName { get; set; }
+        private IFormattedTextImpl impl;
+
+        public FormattedText()
+        {
+            this.impl = Locator.Current.GetService<IFormattedTextImpl>();
+        }
+
+        public Size Constraint
+        {
+            get { return this.impl.Constraint; }
+            set { this.impl.Constraint = value; }
+        }
+
+        public string FontFamilyName
+        {
+            get { return this.impl.FontFamilyName; }
+            set { this.impl.FontFamilyName = value; }
+        }
+
+        public double FontSize
+        {
+            get { return this.impl.FontSize; }
+            set { this.impl.FontSize = value; }
+        }
+
+        public FontStyle FontStyle
+        {
+            get { return this.impl.FontStyle; }
+            set { this.impl.FontStyle = value; }
+        }
+
+        public string Text
+        {
+            get { return this.impl.Text; }
+            set { this.impl.Text = value; }
+        }
 
-        public double FontSize { get; set; }
+        public TextHitTestResult HitTestPoint(Point point)
+        {
+            return this.impl.HitTestPoint(point);
+        }
 
-        public FontStyle FontStyle { get; set; }
+        public Rect HitTestTextPosition(int index)
+        {
+            return this.impl.HitTestTextPosition(index);
+        }
 
-        public string Text { get; set; }
+        public Size Measure()
+        {
+            return this.impl.Measure();
+        }
     }
 }

Perspex.SceneGraph/Media/TextHitTestResult.cs

@@ -0,0 +1,15 @@
+// -----------------------------------------------------------------------
+// <copyright file="TextHitTestResult.cs" company="Steven Kirk">
+// Copyright 2014 MIT Licence. See licence.md for more information.
+// </copyright>
+// -----------------------------------------------------------------------
+
+namespace Perspex.Media
+{
+    public class TextHitTestResult
+    {
+        public int TextPosition { get; set; }
+
+        public bool IsTrailing { get; set; }
+    }
+}

Perspex.SceneGraph/Perspex.SceneGraph.csproj

@@ -62,8 +62,10 @@
     <Compile Include="Media\StreamGeometry.cs" />
     <Compile Include="Media\StreamGeometryContext.cs" />
     <Compile Include="Media\Stretch.cs" />
+    <Compile Include="Media\TextHitTestResult.cs" />
     <Compile Include="Media\Transform.cs" />
     <Compile Include="Origin.cs" />
+    <Compile Include="Platform\IFormattedTextImpl.cs" />
     <Compile Include="Platform\IBitmapImpl.cs" />
     <Compile Include="Platform\IGeometryImpl.cs" />
     <Compile Include="Platform\IPlatformRenderInterface.cs" />

Perspex.SceneGraph/Platform/IFormattedTextImpl.cs

@@ -0,0 +1,29 @@
+// -----------------------------------------------------------------------
+// <copyright file="IFormattedTextImpl.cs" company="Steven Kirk">
+// Copyright 2014 MIT Licence. See licence.md for more information.
+// </copyright>
+// -----------------------------------------------------------------------
+
+namespace Perspex.Platform
+{
+    using Perspex.Media;
+
+    public interface IFormattedTextImpl
+    {
+        Size Constraint { get; set; }
+
+        string FontFamilyName { get; set; }
+
+        double FontSize { get; set; }
+
+        FontStyle FontStyle { get; set; }
+
+        string Text { get; set; }
+
+        TextHitTestResult HitTestPoint(Point point);
+
+        Rect HitTestTextPosition(int index);
+
+        Size Measure();
+    }
+}

Perspex.SceneGraph/Platform/ITextService.cs

@@ -6,8 +6,10 @@
 
 namespace Perspex.Platform
 {
+    using System;
     using Perspex.Media;
 
+    [Obsolete("Use methods on FormattedText instead.")]
     public interface ITextService
     {
         int GetCaretIndex(FormattedText text, Point point, Size constraint);

Windows/Perspex.Direct2D1/Direct2D1Platform.cs

@@ -33,10 +33,10 @@ namespace Perspex.Direct2D1
         {
             var locator = Locator.CurrentMutable;
             locator.Register(() => instance, typeof(IPlatformRenderInterface));
-            locator.Register(() => textService, typeof(ITextService));
             locator.Register(() => d2d1Factory, typeof(SharpDX.Direct2D1.Factory));
             locator.Register(() => dwfactory, typeof(SharpDX.DirectWrite.Factory));
             locator.Register(() => imagingFactory, typeof(SharpDX.WIC.ImagingFactory));
+            locator.Register(() => new FormattedTextImpl(), typeof(IFormattedTextImpl));
         }
 
         public IBitmapImpl CreateBitmap(int width, int height)

Windows/Perspex.Direct2D1/Media/FormattedTextImpl.cs

@@ -0,0 +1,182 @@
+// -----------------------------------------------------------------------
+// <copyright file="TextService.cs" company="Steven Kirk">
+// Copyright 2014 MIT Licence. See licence.md for more information.
+// </copyright>
+// -----------------------------------------------------------------------
+
+namespace Perspex.Direct2D1.Media
+{
+    using System;
+    using Perspex.Media;
+    using Perspex.Platform;
+    using Splat;
+    using DWrite = SharpDX.DirectWrite;
+
+    public class FormattedTextImpl : IFormattedTextImpl
+    {
+        private string text;
+
+        private string fontFamilyName = "Ariel";
+
+        private double fontSize = 10;
+
+        private FontStyle fontStyle;
+
+        private DWrite.Factory factory;
+
+        private DWrite.TextLayout layout;
+
+        public FormattedTextImpl()
+        {
+            this.factory = Locator.Current.GetService<DWrite.Factory>();
+        }
+
+        public Size Constraint
+        {
+            get
+            {
+                return new Size(this.Layout.MaxWidth, this.Layout.MaxHeight);
+            }
+
+            set
+            {
+                this.Layout.MaxWidth = (float)value.Width;
+                this.Layout.MaxHeight = (float)value.Height;
+            }
+        }
+
+        public string FontFamilyName
+        {
+            get
+            {
+                return this.fontFamilyName;
+            }
+
+            set
+            {
+                if (this.fontFamilyName != value)
+                {
+                    this.fontFamilyName = value;
+                    this.DisposeLayout();
+                }
+            }
+        }
+
+        public double FontSize
+        {
+            get
+            {
+                return this.fontSize;
+            }
+
+            set
+            {
+                if (this.fontSize != value)
+                {
+                    this.fontSize = value;
+                    this.DisposeLayout();
+                }
+            }
+        }
+
+        public FontStyle FontStyle
+        {
+            get
+            {
+                return this.fontStyle;
+            }
+
+            set
+            {
+                if (this.fontStyle != value)
+                {
+                    this.fontStyle = value;
+                    this.DisposeLayout();
+                }
+            }
+        }
+
+        public string Text
+        {
+            get
+            {
+                return this.text;
+            }
+
+            set
+            {
+                if (this.text != value)
+                {
+                    this.text = value;
+                    this.DisposeLayout();
+                }
+            }
+        }
+
+        public DWrite.TextLayout Layout
+        {
+            get
+            {
+                if (this.layout == null)
+                {
+                    this.layout = new DWrite.TextLayout(
+                        this.factory,
+                        this.text ?? string.Empty,
+                        new DWrite.TextFormat(this.factory, this.fontFamilyName, (float)this.fontSize),
+                        float.MaxValue,
+                        float.MaxValue);
+                }
+
+                return this.layout;
+            }
+        }
+
+        public TextHitTestResult HitTestPoint(Point point)
+        {
+            SharpDX.Bool isTrailingHit;
+            SharpDX.Bool isInside;
+
+            DWrite.HitTestMetrics result = layout.HitTestPoint(
+                (float)point.X,
+                (float)point.Y,
+                out isTrailingHit,
+                out isInside);
+
+            return new TextHitTestResult
+            {
+                TextPosition = result.TextPosition,
+                IsTrailing = isTrailingHit,
+            };
+        }
+
+        public Rect HitTestTextPosition(int index)
+        {
+            float x;
+            float y;
+
+            DWrite.HitTestMetrics result = layout.HitTestTextPosition(
+                index, 
+                false, 
+                out x, 
+                out y);
+
+            return new Rect(result.Left, result.Top, result.Width, result.Height);
+        }
+
+        public Size Measure()
+        {
+            return new Size(
+                layout.Metrics.WidthIncludingTrailingWhitespace,
+                layout.Metrics.Height);
+        }
+
+        private void DisposeLayout()
+        {
+            if (this.layout != null)
+            {
+                this.layout.Dispose();
+                this.layout = null;
+            }
+        }
+    }
+}

Windows/Perspex.Direct2D1/TextService.cs → Windows/Perspex.Direct2D1/Media/TextService.cs

@@ -4,7 +4,7 @@
 // </copyright>
 // -----------------------------------------------------------------------
 
-namespace Perspex.Direct2D1
+namespace Perspex.Direct2D1.Media
 {
     using System;
     using System.Linq;

Windows/Perspex.Direct2D1/Perspex.Direct2D1.csproj

@@ -73,10 +73,11 @@
     <Compile Include="Media\StreamGeometryContextImpl.cs" />
     <Compile Include="Media\GeometryImpl.cs" />
     <Compile Include="Media\StreamGeometryImpl.cs" />
+    <Compile Include="Media\FormattedTextImpl.cs" />
     <Compile Include="PrimitiveExtensions.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Renderer.cs" />
-    <Compile Include="TextService.cs" />
+    <Compile Include="Media\TextService.cs" />
   </ItemGroup>
   <ItemGroup>
     <None Include="app.config" />