Make Home key work in multi-line text boxes.

Cairo/Perspex.Cairo/Media/FormattedTextImpl.cs

@@ -56,6 +56,11 @@ namespace Perspex.Cairo.Media
             this.Layout.Dispose();
         }
 
+        public IEnumerable<FormattedTextLine> GetLines()
+        {
+            return new FormattedTextLine[0];
+        }
+
         public TextHitTestResult HitTestPoint(Point point)
         {
             int textPosition;

Perspex.Controls/TextBox.cs

@@ -137,6 +137,44 @@ namespace Perspex.Controls
             }
         }
 
+        private void MoveHome(ModifierKeys modifiers)
+        {
+            var caretIndex = this.CaretIndex;
+
+            if ((modifiers & ModifierKeys.Control) != 0)
+            {
+                caretIndex = 0;
+            }
+            else
+            {
+                var lines = this.textBoxView.FormattedText.GetLines();
+                var pos = 0;
+
+                foreach (var line in lines)
+                {
+                    if (pos + line.Length > caretIndex)
+                    {
+                        break;
+                    }
+
+                    pos += line.Length;
+                }
+
+                caretIndex = pos;
+            }
+
+            this.CaretIndex = caretIndex;
+
+            if ((modifiers & ModifierKeys.Shift) != 0)
+            {
+                this.SelectionEnd = caretIndex;
+            }
+            else
+            {
+                this.SelectionStart = this.SelectionEnd = caretIndex;
+            }
+        }
+
         private void OnKeyDown(object sender, KeyEventArgs e)
         {
             string text = this.Text ?? string.Empty;
@@ -162,7 +200,7 @@ namespace Perspex.Controls
                     break;
 
                 case Key.Home:
-                    this.CaretIndex = 0;
+                    this.MoveHome(e.Device.Modifiers);
                     break;
 
                 case Key.End:
@@ -257,7 +295,8 @@ namespace Perspex.Controls
         private void OnPointerPressed(object sender, PointerEventArgs e)
         {
             var point = e.GetPosition(this.textBoxView);
-            this.CaretIndex = this.textBoxView.GetCaretIndex(point);
+            this.CaretIndex = this.SelectionStart = this.SelectionEnd = 
+                this.textBoxView.GetCaretIndex(point);
         }
     }
 }

Perspex.Controls/TextBoxView.cs

@@ -36,6 +36,11 @@ namespace Perspex.Controls
             parent.GetObservable(TextBox.CaretIndexProperty).Subscribe(_ => this.CaretMoved());
         }
 
+        public new FormattedText FormattedText
+        {
+            get { return base.FormattedText; }
+        }
+
         public int GetCaretIndex(Point point)
         {
             var hit = this.FormattedText.HitTestPoint(point);

Perspex.SceneGraph/Media/FormattedText.cs

@@ -69,6 +69,11 @@ namespace Perspex.Media
             this.PlatformImpl.Dispose();
         }
 
+        public IEnumerable<FormattedTextLine> GetLines()
+        {
+            return this.PlatformImpl.GetLines();
+        }
+
         public TextHitTestResult HitTestPoint(Point point)
         {
             return this.PlatformImpl.HitTestPoint(point);

Perspex.SceneGraph/Media/FormattedTextLine.cs

@@ -0,0 +1,21 @@
+// -----------------------------------------------------------------------
+// <copyright file="FormattedTextLine.cs" company="Steven Kirk">
+// Copyright 2013 MIT Licence. See licence.md for more information.
+// </copyright>
+// -----------------------------------------------------------------------
+
+namespace Perspex.Media
+{
+    public class FormattedTextLine
+    {
+        public FormattedTextLine(int length, double height)
+        {
+            this.Length = length;
+            this.Height = height;
+        }
+
+        public int Length { get; private set; }
+
+        public double Height { get; private set; }
+    }
+} 

Perspex.SceneGraph/Perspex.SceneGraph.csproj

@@ -46,6 +46,7 @@
     <Compile Include="Media\Color.cs" />
     <Compile Include="Media\Colors.cs" />
     <Compile Include="Media\FontStyle.cs" />
+    <Compile Include="Media\FormattedTextLine.cs" />
     <Compile Include="Media\FormattedText.cs" />
     <Compile Include="Media\Geometry.cs" />
     <Compile Include="Media\IDrawingContext.cs" />

Perspex.SceneGraph/Platform/IFormattedTextImpl.cs

@@ -14,6 +14,8 @@ namespace Perspex.Platform
     {
         Size Constraint { get; set; }
 
+        IEnumerable<FormattedTextLine> GetLines();
+
         TextHitTestResult HitTestPoint(Point point);
 
         Rect HitTestTextPosition(int index);

Windows/Perspex.Direct2D1/Media/FormattedTextImpl.cs

@@ -57,6 +57,12 @@ namespace Perspex.Direct2D1.Media
             this.TextLayout.Dispose();
         }
 
+        public IEnumerable<FormattedTextLine> GetLines()
+        {
+            var result = this.TextLayout.GetLineMetrics();
+            return from line in result select new FormattedTextLine(line.Length, line.Height);
+        }
+
         public TextHitTestResult HitTestPoint(Point point)
         {
             SharpDX.Bool isTrailingHit;