[WIP] New unified TextLayout

samples/ControlCatalog/Pages/ScreenPage.cs

@@ -49,23 +49,24 @@ public override void Render(DrawingContext context)
 
                     FormattedText text = new FormattedText()
                     {
-                        Typeface = Typeface.Default
+                        Typeface = Typeface.Default,
+                        Foreground = Brushes.Black
                     };
 
                     text.Text = $"Bounds: {screen.Bounds.Width}:{screen.Bounds.Height}";
-                    context.DrawText(Brushes.Black, boundsRect.Position.WithY(boundsRect.Size.Height), text);
+                    context.DrawText(text, boundsRect.Position.WithY(boundsRect.Size.Height));
 
                     text.Text = $"WorkArea: {screen.WorkingArea.Width}:{screen.WorkingArea.Height}";
-                    context.DrawText(Brushes.Black, boundsRect.Position.WithY(boundsRect.Size.Height + 20), text);
+                    context.DrawText(text, boundsRect.Position.WithY(boundsRect.Size.Height + 20));
 
                     text.Text = $"Scaling: {screen.PixelDensity * 100}%";
-                    context.DrawText(Brushes.Black, boundsRect.Position.WithY(boundsRect.Size.Height + 40), text);
+                    context.DrawText(text, boundsRect.Position.WithY(boundsRect.Size.Height + 40));
 
                     text.Text = $"Primary: {screen.Primary}";
-                    context.DrawText(Brushes.Black, boundsRect.Position.WithY(boundsRect.Size.Height + 60), text);
+                    context.DrawText(text, boundsRect.Position.WithY(boundsRect.Size.Height + 60));
 
                     text.Text = $"Current: {screen.Equals(w.Screens.ScreenFromBounds(new PixelRect(w.Position, PixelSize.FromSize(w.Bounds.Size, scaling))))}";
-                    context.DrawText(Brushes.Black, boundsRect.Position.WithY(boundsRect.Size.Height + 80), text);
+                    context.DrawText(text, boundsRect.Position.WithY(boundsRect.Size.Height + 80));
                 }
 
             context.DrawRectangle(p, new Rect(w.Position.X / 10f + Math.Abs(_leftMost), w.Position.Y / 10, w.Bounds.Width / 10, w.Bounds.Height / 10));

samples/RenderDemo/Pages/CustomSkiaPage.cs

@@ -41,7 +41,7 @@ public void Render(IDrawingContextImpl context)
             {
                 var canvas = (context as ISkiaDrawingContextImpl)?.SkCanvas;
                 if (canvas == null)
-                    context.DrawText(Brushes.Black, new Point(), _noSkia.PlatformImpl);
+                    _noSkia.TextLayout.Draw (context, Brushes.Black, new Point());
                 else
                 {
                     canvas.Save();

src/Avalonia.Controls/Presenters/TextPresenter.cs

@@ -135,7 +135,7 @@ public int SelectionEnd
         public int GetCaretIndex(Point point)
         {
             var hit = FormattedText.HitTestPoint(point);
-            return hit.TextPosition + (hit.IsTrailing ? 1 : 0);
+            return hit.CharacterHit.FirstCharacterIndex + hit.CharacterHit.TrailingLength;
         }
 
         public override void Render(DrawingContext context)
@@ -145,6 +145,8 @@ public override void Render(DrawingContext context)
 
             if (selectionStart != selectionEnd)
             {
+                var selectionBrush = SelectionBrush;
+
                 var start = Math.Min(selectionStart, selectionEnd);
                 var length = Math.Max(selectionStart, selectionEnd) - start;
 
@@ -156,7 +158,7 @@ public override void Render(DrawingContext context)
 
                 foreach (var rect in rects)
                 {
-                    context.FillRectangle(SelectionBrush, rect);
+                    context.FillRectangle(selectionBrush, rect);
                 }
             }
 
@@ -277,7 +279,7 @@ protected override FormattedText CreateFormattedText(Size constraint, string tex
             {
                 result.Spans = new[]
                 {
-                    new FormattedTextStyleSpan(start, length, SelectionForegroundBrush),
+                    new FormattedTextStyleSpan(start, length, foreground: SelectionForegroundBrush),
                 };
             }
 

src/Avalonia.Controls/TextBlock.cs

@@ -87,6 +87,12 @@ public class TextBlock : Control
         public static readonly StyledProperty<TextWrapping> TextWrappingProperty =
             AvaloniaProperty.Register<TextBlock, TextWrapping>(nameof(TextWrapping));
 
+        /// <summary>
+        /// Defines the <see cref="TextTrimming"/> property.
+        /// </summary>
+        public static readonly StyledProperty<TextTrimming> TextTrimmingProperty =
+            AvaloniaProperty.Register<TextBlock, TextTrimming>(nameof(TextTrimming));
+
         private string _text;
         private FormattedText _formattedText;
         private Size _constraint;
@@ -109,7 +115,8 @@ static TextBlock()
                 TextAlignmentProperty.Changed,
                 FontSizeProperty.Changed,
                 FontStyleProperty.Changed,
-                FontWeightProperty.Changed
+                FontWeightProperty.Changed,
+                TextTrimmingProperty.Changed
             ).AddClassHandler<TextBlock>((x,_) => x.OnTextPropertiesChanged());
         }
 
@@ -219,6 +226,15 @@ public TextAlignment TextAlignment
             set { SetValue(TextAlignmentProperty, value); }
         }
 
+        /// <summary>
+        /// Gets or sets the text trimming.
+        /// </summary>
+        public TextTrimming TextTrimming
+        {
+            get { return GetValue(TextTrimmingProperty); }
+            set { SetValue(TextTrimmingProperty, value); }
+        }
+
         /// <summary>
         /// Gets the value of the attached <see cref="FontFamilyProperty"/> on a control.
         /// </summary>
@@ -338,7 +354,8 @@ public override void Render(DrawingContext context)
             }
 
             FormattedText.Constraint = Bounds.Size;
-            context.DrawText(Foreground, new Point(), FormattedText);
+
+            context.DrawText(FormattedText, new Point());
         }
 
         /// <summary>
@@ -354,9 +371,11 @@ protected virtual FormattedText CreateFormattedText(Size constraint, string text
                 Constraint = constraint,
                 Typeface = FontManager.Current?.GetOrAddTypeface(FontFamily, FontWeight, FontStyle),
                 FontSize = FontSize,
+                Foreground = Foreground,
                 Text = text ?? string.Empty,
                 TextAlignment = TextAlignment,
                 TextWrapping = TextWrapping,
+                TextTrimming = TextTrimming
             };
         }
 

src/Avalonia.Controls/TextBox.cs

@@ -1,20 +1,22 @@
 // Copyright (c) The Avalonia Project. All rights reserved.
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
-using Avalonia.Input.Platform;
 using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Reactive.Linq;
 using Avalonia.Controls.Presenters;
 using Avalonia.Controls.Primitives;
 using Avalonia.Controls.Utils;
+using Avalonia.Data;
 using Avalonia.Input;
+using Avalonia.Input.Platform;
 using Avalonia.Interactivity;
 using Avalonia.Media;
 using Avalonia.Metadata;
 using Avalonia.Data;
 using Avalonia.Utilities;
+using Avalonia.Media.Text;
 
 namespace Avalonia.Controls
 {
@@ -110,6 +112,8 @@ public UndoRedoState(string text, int caretPosition)
         private string _newLine = Environment.NewLine;
         private static readonly string[] invalidCharacters = new String[1] { "\u007f" };
 
+        private CharacterHit _characterHit;
+
         static TextBox()
         {
             FocusableProperty.OverrideDefaultValue(typeof(TextBox), true);
@@ -250,9 +254,9 @@ public string Text
                 if (!_ignoreTextChanges)
                 {
                     var caretIndex = CaretIndex;
-                    SelectionStart = CoerceCaretIndex(SelectionStart, value);
-                    SelectionEnd = CoerceCaretIndex(SelectionEnd, value);
-                    CaretIndex = CoerceCaretIndex(caretIndex, value);
+                    SelectionStart = CoerceCaretIndex(SelectionStart, value?.Length ?? 0);
+                    SelectionEnd = CoerceCaretIndex(SelectionEnd, value?.Length ?? 0);
+                    CaretIndex = CoerceCaretIndex(caretIndex, value?.Length ?? 0);
 
                     if (SetAndRaise(TextProperty, ref _text, value) && !_isUndoingRedoing)
                     {
@@ -566,9 +570,12 @@ protected override void OnKeyDown(KeyEventArgs e)
                             // handle deleting /r/n
                             // you don't ever want to leave a dangling /r around. So, if deleting /n, check to see if 
                             // a /r should also be deleted.
-                            if (CaretIndex > 1 &&
-                                text[CaretIndex - 1] == '\n' &&
-                                text[CaretIndex - 2] == '\r')
+                            if (CaretIndex > 1 && text[CaretIndex - 1] == '\n' && text[CaretIndex - 2] == '\r')
+                            {
+                                removedCharacters = 2;
+                            }
+
+                            if (caretIndex >= 2 && char.IsSurrogatePair(text[caretIndex - 2], text[caretIndex - 1]))
                             {
                                 removedCharacters = 2;
                             }
@@ -590,16 +597,7 @@ protected override void OnKeyDown(KeyEventArgs e)
 
                         if (!DeleteSelection() && caretIndex < text.Length)
                         {
-                            var removedCharacters = 1;
-                            // handle deleting /r/n
-                            // you don't ever want to leave a dangling /r around. So, if deleting /n, check to see if 
-                            // a /r should also be deleted.
-                            if (CaretIndex < text.Length - 1 &&
-                                text[caretIndex + 1] == '\n' &&
-                                text[caretIndex] == '\r')
-                            {
-                                removedCharacters = 2;
-                            }
+                            var removedCharacters = _characterHit.TrailingLength;
 
                             SetTextInternal(text.Substring(0, caretIndex) +
                                             text.Substring(caretIndex + removedCharacters));
@@ -654,7 +652,13 @@ protected override void OnKeyDown(KeyEventArgs e)
         protected override void OnPointerPressed(PointerPressedEventArgs e)
         {
             var point = e.GetPosition(_presenter);
-            var index = CaretIndex = _presenter.GetCaretIndex(point);
+
+            var hitTestResult = _presenter.FormattedText.HitTestPoint(point);
+
+            _characterHit = hitTestResult.CharacterHit;
+
+            var index = CaretIndex = _characterHit.FirstCharacterIndex + _characterHit.TrailingLength;
+
             var text = Text;
 
             if (text != null && e.MouseButton == MouseButton.Left)
@@ -710,55 +714,21 @@ protected override void UpdateDataValidation(AvaloniaProperty property, BindingN
             }
         }
 
-        private int CoerceCaretIndex(int value) => CoerceCaretIndex(value, Text);
+        private int CoerceCaretIndex(int value) => CoerceCaretIndex(value, Text?.Length ?? 0);
 
-        private int CoerceCaretIndex(int value, string text)
+        private int CoerceCaretIndex(int value, int length)
         {
-            if (text == null)
-            {
-                return 0;
-            }
-            var length = text.Length;
-
             if (value < 0)
             {
                 return 0;
             }
-            else if (value > length)
-            {
-                return length;
-            }
-            else if (value > 0 && text[value - 1] == '\r' && value < length && text[value] == '\n')
-            {
-                return value + 1;
-            }
-            else
-            {
-                return value;
-            }
-        }
-
-        private int DeleteCharacter(int index)
-        {
-            var start = index + 1;
-            var text = Text;
-            var c = text[index];
-            var result = 1;
 
-            if (c == '\n' && index > 0 && text[index - 1] == '\r')
-            {
-                --index;
-                ++result;
-            }
-            else if (c == '\r' && index < text.Length - 1 && text[index + 1] == '\n')
+            if (value > length)
             {
-                ++start;
-                ++result;
+                return length;
             }
 
-            Text = text.Substring(0, index) + text.Substring(start);
-
-            return result;
+            return value;
         }
 
         private void MoveHorizontal(int direction, bool wholeWord)
@@ -780,16 +750,11 @@ private void MoveHorizontal(int direction, bool wholeWord)
                     return;
                 }
 
-                var c = text[index];
+                var rect = _presenter.FormattedText.HitTestTextPosition(index);
 
-                if (direction > 0)
-                {
-                    CaretIndex += (c == '\r' && index < text.Length - 1 && text[index + 1] == '\n') ? 2 : 1;
-                }
-                else
-                {
-                    CaretIndex -= (c == '\n' && index > 0 && text[index - 1] == '\r') ? 2 : 1;
-                }
+                var hitTestResult = _presenter.FormattedText.HitTestPoint(new Point(rect.X, rect.Y));
+
+                CaretIndex = hitTestResult.CharacterHit.FirstCharacterIndex;
             }
             else
             {
@@ -807,7 +772,7 @@ private void MoveHorizontal(int direction, bool wholeWord)
         private bool MoveVertical(int count)
         {
             var formattedText = _presenter.FormattedText;
-            var lines = formattedText.GetLines().ToList();
+            var lines = formattedText.TextLayout.TextLines;
             var caretIndex = CaretIndex;
             var lineIndex = GetLine(caretIndex, lines) + count;
 
@@ -816,15 +781,12 @@ private bool MoveVertical(int count)
                 var line = lines[lineIndex];
                 var rect = formattedText.HitTestTextPosition(caretIndex);
                 var y = count < 0 ? rect.Y : rect.Bottom;
-                var point = new Point(rect.X, y + (count * (line.Height / 2)));
+                var point = new Point(rect.X, y + (count * (line.LineMetrics.Size.Height / 2)));
                 var hit = formattedText.HitTestPoint(point);
-                CaretIndex = hit.TextPosition + (hit.IsTrailing ? 1 : 0);
+                CaretIndex = hit.CharacterHit.FirstCharacterIndex + hit.CharacterHit.TrailingLength;
                 return true;
             }
-            else
-            {
-                return false;
-            }
+            return false;
         }
 
         private void MoveHome(bool document)
@@ -838,17 +800,17 @@ private void MoveHome(bool document)
             }
             else
             {
-                var lines = _presenter.FormattedText.GetLines();
+                var lines = _presenter.FormattedText.TextLayout.TextLines;
                 var pos = 0;
 
                 foreach (var line in lines)
                 {
-                    if (pos + line.Length > caretIndex || pos + line.Length == text.Length)
+                    if (pos + line.Text.Length > caretIndex || pos + line.Text.Length == text.Length)
                     {
                         break;
                     }
 
-                    pos += line.Length;
+                    pos += line.Text.Length;
                 }
 
                 caretIndex = pos;
@@ -868,12 +830,12 @@ private void MoveEnd(bool document)
             }
             else
             {
-                var lines = _presenter.FormattedText.GetLines();
+                var lines = _presenter.FormattedText.TextLayout.TextLines;
                 var pos = 0;
 
                 foreach (var line in lines)
                 {
-                    pos += line.Length;
+                    pos += line.Text.Length;
 
                     if (pos > caretIndex)
                     {
@@ -945,15 +907,15 @@ private string GetSelection()
             return text.Substring(start, end - start);
         }
 
-        private int GetLine(int caretIndex, IList<FormattedTextLine> lines)
+        private int GetLine(int caretIndex, IReadOnlyList<TextLine> lines)
         {
             int pos = 0;
             int i;
 
             for (i = 0; i < lines.Count - 1; ++i)
             {
                 var line = lines[i];
-                pos += line.Length;
+                pos += line.Text.Length;
 
                 if (pos > caretIndex)
                 {