Merge pull request #7693 from Gillibald/fixes/textProcessingBugs

Fixes text processing bugs

src/Avalonia.Controls/Presenters/TextPresenter.cs

@@ -395,9 +395,13 @@ namespace Avalonia.Controls.Presenters
             var y = Math.Floor(_caretBounds.Y) + 0.5;
             var b = Math.Ceiling(_caretBounds.Bottom) - 0.5;
             
-            if (x >= Bounds.Width)
+            var caretIndex = _lastCharacterHit.FirstCharacterIndex + _lastCharacterHit.TrailingLength;
+            var lineIndex = TextLayout.GetLineIndexFromCharacterIndex(caretIndex, _lastCharacterHit.TrailingLength > 0);
+            var textLine = TextLayout.TextLines[lineIndex];
+
+            if (_caretBounds.X > 0 && _caretBounds.X >= textLine.WidthIncludingTrailingWhitespace)
             {
-                x = Math.Floor(_caretBounds.X - 1) + 0.5;
+                x -= 1;
             }
             
             return (new Point(x, y), new Point(x, b));
@@ -468,8 +472,8 @@ namespace Avalonia.Controls.Presenters
 
             var typeface = new Typeface(FontFamily, FontStyle, FontWeight);
 
-            var selectionStart = SelectionStart;
+            var selectionStart = CoerceCaretIndex(SelectionStart);
-            var selectionEnd = SelectionEnd;
+            var selectionEnd = CoerceCaretIndex(SelectionEnd);
             var start = Math.Min(selectionStart, selectionEnd);
             var length = Math.Max(selectionStart, selectionEnd) - start;
 
@@ -513,9 +517,7 @@ namespace Avalonia.Controls.Presenters
             
             InvalidateArrange();
 
-            var scale = LayoutHelper.GetLayoutScale(this);
+            var measuredSize = PixelSize.FromSize(TextLayout.Bounds.Size, 1);
-
-            var measuredSize = PixelSize.FromSize(TextLayout.Bounds.Size, scale);
             
             return new Size(measuredSize.Width, measuredSize.Height);
         }

src/Avalonia.Controls/TextBlock.cs

@@ -550,9 +550,7 @@ namespace Avalonia.Controls
 
             InvalidateArrange();
 
-            var scale = LayoutHelper.GetLayoutScale(this);
+            var measuredSize = PixelSize.FromSize(TextLayout.Bounds.Size, 1);
-
-            var measuredSize = PixelSize.FromSize(TextLayout.Bounds.Size, scale);
 
             return new Size(measuredSize.Width, measuredSize.Height).Inflate(padding);
         }

src/Avalonia.Controls/TextBox.cs

@@ -257,6 +257,8 @@ namespace Avalonia.Controls
                 UndoRedoState state;
                 if (IsUndoEnabled && _undoRedoHelper.TryGetLastState(out state) && state.Text == Text)
                     _undoRedoHelper.UpdateLastState();
+
+                SelectionStart = SelectionEnd = value;
             }
         }
 
@@ -301,14 +303,15 @@ namespace Avalonia.Controls
             {
                 value = CoerceCaretIndex(value);
                 var changed = SetAndRaise(SelectionStartProperty, ref _selectionStart, value);
+                
                 if (changed)
                 {
                     UpdateCommandStates();
                 }
 
-                if (value == SelectionEnd)
+                if (SelectionEnd == value && CaretIndex != value)
                 {
-                    CaretIndex = SelectionStart;
+                    CaretIndex = value;
                 }
             }
         }
@@ -330,7 +333,7 @@ namespace Avalonia.Controls
                     UpdateCommandStates();
                 }
                 
-                if (value == SelectionStart)
+                if (SelectionStart == value && CaretIndex != value)
                 {
                     CaretIndex = value;
                 }
@@ -352,10 +355,12 @@ namespace Avalonia.Controls
                 if (!_ignoreTextChanges)
                 {
                     var caretIndex = CaretIndex;
+                    var selectionStart = SelectionStart;
+                    var selectionEnd = SelectionEnd;
                     
-                    SelectionStart = CoerceCaretIndex(SelectionStart, value);
-                    SelectionEnd = CoerceCaretIndex(SelectionEnd, value);
                     CaretIndex = CoerceCaretIndex(caretIndex, value);
+                    SelectionStart = CoerceCaretIndex(selectionStart, value);
+                    SelectionEnd = CoerceCaretIndex(selectionEnd, value);
 
                     if (SetAndRaise(TextProperty, ref _text, value) && IsUndoEnabled && !_isUndoingRedoing)
                     {
@@ -458,7 +463,7 @@ namespace Avalonia.Controls
         /// </summary>
         public void ClearSelection()
         {
-            SelectionStart = SelectionEnd = CaretIndex;
+            CaretIndex = SelectionStart;
         }
 
         /// <summary>
@@ -856,6 +861,7 @@ namespace Avalonia.Controls
                 movement = true;
                 selection = false;
                 handled = true;
+                CaretIndex = _presenter.CaretIndex;
             }
             else if (Match(keymap.MoveCursorToTheEndOfDocument))
             {
@@ -863,6 +869,7 @@ namespace Avalonia.Controls
                 movement = true;
                 selection = false;
                 handled = true;
+                CaretIndex = _presenter.CaretIndex;
             }
             else if (Match(keymap.MoveCursorToTheStartOfLine))
             {
@@ -870,7 +877,7 @@ namespace Avalonia.Controls
                 movement = true;
                 selection = false;
                 handled = true;
-
+                CaretIndex = _presenter.CaretIndex;
             }
             else if (Match(keymap.MoveCursorToTheEndOfLine))
             {
@@ -878,6 +885,7 @@ namespace Avalonia.Controls
                 movement = true;
                 selection = false;
                 handled = true;
+                CaretIndex = _presenter.CaretIndex;
             }
             else if (Match(keymap.MoveCursorToTheStartOfDocumentWithSelection))
             {
@@ -950,7 +958,7 @@ namespace Avalonia.Controls
                         }
                         else
                         {
-                            SelectionStart = SelectionEnd = _presenter.CaretIndex;
+                            CaretIndex = _presenter.CaretIndex;
                         }
                         
                         break;
@@ -972,7 +980,7 @@ namespace Avalonia.Controls
                         }
                         else
                         {
-                            SelectionStart = SelectionEnd = _presenter.CaretIndex;
+                            CaretIndex = _presenter.CaretIndex;
                         }
                         
                         break;
@@ -996,6 +1004,8 @@ namespace Avalonia.Controls
 
                             SetTextInternal(text.Substring(0, length) +
                                             text.Substring(caretIndex));
+
+                            CaretIndex = _presenter.CaretIndex;
                         }
                         
                         SnapshotUndoRedo();
@@ -1070,8 +1080,6 @@ namespace Avalonia.Controls
             {
                 e.Handled = true;
             }
-
-            CaretIndex = _presenter.CaretIndex;
         }
 
         protected override void OnPointerPressed(PointerPressedEventArgs e)
@@ -1240,6 +1248,7 @@ namespace Avalonia.Controls
         {
             var text = Text ?? string.Empty;
             var selectionStart = SelectionStart;
+            var selectionEnd = SelectionEnd;
 
             if (!wholeWord)
             {
@@ -1248,15 +1257,32 @@ namespace Avalonia.Controls
                     return;
                 }
                 
-                _presenter.MoveCaretHorizontal(direction > 0 ? LogicalDirection.Forward : LogicalDirection.Backward);
-
                 if (isSelecting)
                 {
+                    _presenter.MoveCaretToTextPosition(selectionEnd);
+                    
+                    _presenter.MoveCaretHorizontal(direction > 0 ?
+                        LogicalDirection.Forward :
+                        LogicalDirection.Backward);
+                    
                     SelectionEnd = _presenter.CaretIndex;
                 }
                 else
                 {
-                    SelectionStart = SelectionEnd = _presenter.CaretIndex;
+                    if (selectionStart != selectionEnd)
+                    {
+                        _presenter.MoveCaretToTextPosition(direction > 0 ?
+                            Math.Max(selectionStart, selectionEnd) :
+                            Math.Min(selectionStart, selectionEnd));
+                    }
+                    else
+                    {
+                        _presenter.MoveCaretHorizontal(direction > 0 ?
+                            LogicalDirection.Forward :
+                            LogicalDirection.Backward);
+                    }
+
+                    CaretIndex = _presenter.CaretIndex;
                 }
             }
             else
@@ -1265,14 +1291,19 @@ namespace Avalonia.Controls
                 
                 if (direction > 0)
                 {
-                    offset = StringUtils.NextWord(text, selectionStart) - selectionStart;
+                    offset = StringUtils.NextWord(text, selectionEnd) - selectionEnd;
                 }
                 else
                 {
-                    offset = StringUtils.PreviousWord(text, selectionStart) - selectionStart;
+                    offset = StringUtils.PreviousWord(text, selectionEnd) - selectionEnd;
                 }
                 
-                SelectionEnd = CaretIndex + offset;
+                SelectionEnd += offset;
+
+                if (!isSelecting)
+                {
+                    CaretIndex = SelectionEnd;
+                }
             }
         }
 
@@ -1316,10 +1347,18 @@ namespace Avalonia.Controls
             else
             {
                 var textLines = _presenter.TextLayout.TextLines;
-                var lineIndex = _presenter.TextLayout.GetLineIndexFromCharacterIndex(caretIndex, false);
+                var lineIndex = _presenter.TextLayout.GetLineIndexFromCharacterIndex(caretIndex, true);
                 var textLine = textLines[lineIndex];
                 
-                _presenter.MoveCaretToTextPosition(textLine.TextRange.Start + textLine.TextRange.Length, true);
+                if (caretIndex == textLine.TextRange.Start + textLine.TextRange.Length  - textLine.NewLineLength &&
+                    lineIndex + 1 < textLines.Count)
+                {
+                    textLine = textLines[++lineIndex];
+                }
+
+                var textPosition = textLine.TextRange.Start + textLine.TextRange.Length - textLine.NewLineLength;
+
+                _presenter.MoveCaretToTextPosition(textPosition, true);
             }
         }
 
@@ -1330,50 +1369,56 @@ namespace Avalonia.Controls
         {
             SelectionStart = 0;
             SelectionEnd = Text?.Length ?? 0;
-            CaretIndex = SelectionEnd;
         }
 
         private bool DeleteSelection(bool raiseTextChanged = true)
         {
-            if (!IsReadOnly)
+            if (IsReadOnly) return true;
-            {
-                var selectionStart = SelectionStart;
-                var selectionEnd = SelectionEnd;
             
-                if (selectionStart != selectionEnd)
+            var selectionStart = SelectionStart;
-                {
+            var selectionEnd = SelectionEnd;
-                    var start = Math.Min(selectionStart, selectionEnd);
+
-                    var end = Math.Max(selectionStart, selectionEnd);
+            if (selectionStart != selectionEnd)
-                    var text = Text!;
-                    SetTextInternal(text.Substring(0, start) + text.Substring(end), raiseTextChanged);
-                    CaretIndex = start;
-                    ClearSelection();
-                    return true;
-                }
-                else
-                {
-                    return false;
-                }
-            }
-            else
             {
+                var start = Math.Min(selectionStart, selectionEnd);
+                var end = Math.Max(selectionStart, selectionEnd);
+                var text = Text!;
+
+                SetTextInternal(text.Substring(0, start) + text.Substring(end), raiseTextChanged);
+                    
+                _presenter?.MoveCaretToTextPosition(start);
+                    
+                CaretIndex= start;
+                    
+                ClearSelection();
+                    
                 return true;
             }
+                
+            CaretIndex = SelectionStart;
+            
+            return false;
         }
 
         private string GetSelection()
         {
             var text = Text;
+            
             if (string.IsNullOrEmpty(text))
+            {
                 return "";
+            }
+               
             var selectionStart = SelectionStart;
             var selectionEnd = SelectionEnd;
             var start = Math.Min(selectionStart, selectionEnd);
             var end = Math.Max(selectionStart, selectionEnd);
+            
             if (start == end || (Text?.Length ?? 0) < end)
             {
                 return "";
             }
+            
             return text.Substring(start, end - start);
         }
 
@@ -1399,9 +1444,11 @@ namespace Avalonia.Controls
 
         private void SetSelectionForControlBackspace()
         {
-            SelectionStart = CaretIndex;
+            var selectionStart = CaretIndex;
             
             MoveHorizontal(-1, true, false);
+
+            SelectionStart = selectionStart;
         }
 
         private void SetSelectionForControlDelete()
@@ -1413,7 +1460,7 @@ namespace Avalonia.Controls
             
             SelectionStart = CaretIndex;
             
-            MoveHorizontal(1, true, false);
+            MoveHorizontal(1, true, true);
 
             if (SelectionEnd < _text.Length && _text[SelectionEnd] == ' ')
             {

src/Avalonia.Visuals/Media/TextFormatting/ShapeableTextCharacters.cs

@@ -22,5 +22,41 @@ namespace Avalonia.Media.TextFormatting
         public override TextRunProperties Properties { get; }
         
         public sbyte BidiLevel { get; }
+
+        public bool CanShapeTogether(ShapeableTextCharacters shapeableTextCharacters)
+        {
+            if (!Text.Buffer.Equals(shapeableTextCharacters.Text.Buffer))
+            {
+                return false;
+            }
+
+            if (Text.Start + Text.Length != shapeableTextCharacters.Text.Start)
+            {
+                return false;
+            }
+
+            if (BidiLevel != shapeableTextCharacters.BidiLevel)
+            {
+                return false;
+            }
+
+            if (!MathUtilities.AreClose(Properties.FontRenderingEmSize,
+                    shapeableTextCharacters.Properties.FontRenderingEmSize))
+            {
+                return false;
+            }
+
+            if (Properties.Typeface != shapeableTextCharacters.Properties.Typeface)
+            {
+                return false;
+            }
+
+            if (Properties.BaselineAlignment != shapeableTextCharacters.Properties.BaselineAlignment)
+            {
+                return false;
+            }
+
+            return true;
+        }
     }
 }

src/Avalonia.Visuals/Media/TextFormatting/TextCharacters.cs

@@ -176,6 +176,12 @@ namespace Avalonia.Media.TextFormatting
 
                 var currentScript = currentGrapheme.FirstCodepoint.Script;
 
+                //Stop at the first missing glyph
+                if (!currentGrapheme.FirstCodepoint.IsBreakChar && !font.TryGetGlyph(currentGrapheme.FirstCodepoint, out _))
+                {
+                    break;
+                }
+                
                 if (currentScript != script)
                 {
                     if (script is Script.Unknown || currentScript != Script.Common &&
@@ -192,12 +198,6 @@ namespace Avalonia.Media.TextFormatting
                     }
                 }
 
-                //Stop at the first missing glyph
-                if (!currentGrapheme.FirstCodepoint.IsBreakChar && !font.TryGetGlyph(currentGrapheme.FirstCodepoint, out _))
-                {
-                    break;
-                }
-
                 length += currentGrapheme.Text.Length;
             }
 

src/Avalonia.Visuals/Media/TextFormatting/TextFormatterImpl.cs

@@ -1,6 +1,8 @@
 using System;
 using System.Collections.Generic;
+using System.Globalization;
 using System.Linq;
+using System.Runtime.InteropServices;
 using Avalonia.Media.TextFormatting.Unicode;
 using Avalonia.Utilities;
 
@@ -171,25 +173,83 @@ namespace Avalonia.Media.TextFormatting
             resolvedFlowDirection =
                 (resolvedEmbeddingLevel & 1) == 0 ? FlowDirection.LeftToRight : FlowDirection.RightToLeft;
 
-            foreach (var shapeableRuns in CoalesceLevels(textRuns, biDi.ResolvedLevels))
+            var shapeableRuns = new List<ShapeableTextCharacters>(textRuns.Count);
+
+            foreach (var coalescedRuns in CoalesceLevels(textRuns, biDi.ResolvedLevels))
+            {
+                shapeableRuns.AddRange(coalescedRuns);
+            }
+
+            for (var index = 0; index < shapeableRuns.Count; index++)
             {
-                for (var index = 0; index < shapeableRuns.Count; index++)
+                var currentRun = shapeableRuns[index];
+                var groupedRuns = new List<ShapeableTextCharacters>(2) { currentRun };
+                var text = currentRun.Text;
+                var start = currentRun.Text.Start;
+                var length = currentRun.Text.Length;
+                var bufferOffset = currentRun.Text.BufferOffset;
+
+                while (index + 1 < shapeableRuns.Count)
                 {
-                    var currentRun = shapeableRuns[index];
+                    var nextRun = shapeableRuns[index + 1];
+
+                    if (currentRun.CanShapeTogether(nextRun))
+                    {
+                        groupedRuns.Add(nextRun);
+
+                        length += nextRun.Text.Length;
+                        
+                        if (start > nextRun.Text.Start)
+                        {
+                            start = nextRun.Text.Start;
+                        }
+
+                        if (bufferOffset > nextRun.Text.BufferOffset)
+                        {
+                            bufferOffset = nextRun.Text.BufferOffset;
+                        }
+
+                        text = new ReadOnlySlice<char>(text.Buffer, start, length, bufferOffset);
                         
-                    var shapedBuffer = TextShaper.Current.ShapeText(currentRun.Text, currentRun.Properties.Typeface.GlyphTypeface,
+                        index++;
-                        currentRun.Properties.FontRenderingEmSize, currentRun.Properties.CultureInfo, currentRun.BidiLevel);
 
-                    var shapedCharacters = new ShapedTextCharacters(shapedBuffer, currentRun.Properties);
+                        currentRun = nextRun;
 
+                        continue;
+                    }
 
-                    shapedTextCharacters.Add(shapedCharacters);
+                    break;
                 }
+
+                shapedTextCharacters.AddRange(ShapeTogether(groupedRuns, text));
             }
 
             return shapedTextCharacters;
         }
 
+        private static IReadOnlyList<ShapedTextCharacters> ShapeTogether(
+            IReadOnlyList<ShapeableTextCharacters> textRuns, ReadOnlySlice<char> text)
+        {
+            var shapedRuns = new List<ShapedTextCharacters>(textRuns.Count);
+            var firstRun = textRuns[0];
+
+            var shapedBuffer = TextShaper.Current.ShapeText(text, firstRun.Properties.Typeface.GlyphTypeface,
+                firstRun.Properties.FontRenderingEmSize, firstRun.Properties.CultureInfo, firstRun.BidiLevel);
+
+            for (var i = 0; i < textRuns.Count; i++)
+            {
+                var currentRun = textRuns[i];
+
+                var splitResult = shapedBuffer.Split(currentRun.Text.Length);
+
+                shapedRuns.Add(new ShapedTextCharacters(splitResult.First, currentRun.Properties));
+
+                shapedBuffer = splitResult.Second!;
+            }
+
+            return shapedRuns;
+        }
+
         /// <summary>
         /// Coalesces ranges of the same bidi level to form <see cref="ShapeableTextCharacters"/>
         /// </summary>

src/Avalonia.Visuals/Media/TextFormatting/TextLayout.cs

@@ -607,7 +607,7 @@ namespace Avalonia.Media.TextFormatting
 
                 textLines.Add(textLine);
 
-                UpdateBounds(textLine,ref left, ref width, ref height);
+                UpdateBounds(textLine, ref left, ref width, ref height);
 
                 previousLine = textLine;
 

src/Avalonia.Visuals/Media/TextFormatting/TextLineImpl.cs

@@ -553,7 +553,7 @@ namespace Avalonia.Media.TextFormatting
                         out _);
 
                 var isAtEnd = foundCharacterHit.FirstCharacterIndex + foundCharacterHit.TrailingLength ==
-                              TextRange.Length;
+                              TextRange.Start + TextRange.Length;
 
                 if (isAtEnd && !run.GlyphRun.IsLeftToRight)
                 {

src/Avalonia.Visuals/Utilities/ReadOnlySlice.cs

@@ -13,7 +13,7 @@ namespace Avalonia.Utilities
     [DebuggerTypeProxy(typeof(ReadOnlySlice<>.ReadOnlySliceDebugView))]
     public readonly struct ReadOnlySlice<T> : IReadOnlyList<T> where T : struct
     {
-        private readonly int _offset;
+        private readonly int _bufferOffset;
         
         /// <summary>
         /// Gets an empty <see cref="ReadOnlySlice{T}"/>
@@ -24,7 +24,7 @@ namespace Avalonia.Utilities
 
         public ReadOnlySlice(ReadOnlyMemory<T> buffer) : this(buffer, 0, buffer.Length) { }
 
-        public ReadOnlySlice(ReadOnlyMemory<T> buffer, int start, int length, int offset = 0)
+        public ReadOnlySlice(ReadOnlyMemory<T> buffer, int start, int length, int bufferOffset = 0)
         {
 #if DEBUG
             if (start.CompareTo(0) < 0)
@@ -41,7 +41,7 @@ namespace Avalonia.Utilities
             _buffer = buffer;
             Start = start;
             Length = length;
-            _offset = offset;
+            _bufferOffset = bufferOffset;
         }
 
         /// <summary>
@@ -74,12 +74,17 @@ namespace Avalonia.Utilities
         public bool IsEmpty => Length == 0;
 
         /// <summary>
-        ///     The underlying span.
+        ///     Get the underlying span.
         /// </summary>
-        public ReadOnlySpan<T> Span => _buffer.Span.Slice(_offset, Length);
+        public ReadOnlySpan<T> Span => _buffer.Span.Slice(_bufferOffset, Length);
 
         /// <summary>
-        ///     The underlying buffer.
+        ///     Get the buffer offset.
+        /// </summary>
+        public int BufferOffset => _bufferOffset;
+        
+        /// <summary>
+        ///     Get the underlying buffer.
         /// </summary>
         public ReadOnlyMemory<T> Buffer => _buffer;
 
@@ -124,17 +129,17 @@ namespace Avalonia.Utilities
                 return Empty;
             }
 
-            if (start < 0 || _offset + start > _buffer.Length - 1)
+            if (start < 0 || _bufferOffset + start > _buffer.Length - 1)
             {
                 throw new ArgumentOutOfRangeException(nameof(start));
             }
 
-            if (_offset + start + length > _buffer.Length)
+            if (_bufferOffset + start + length > _buffer.Length)
             {
                 throw new ArgumentOutOfRangeException(nameof(length));
             }
 
-            return new ReadOnlySlice<T>(_buffer, start, length, _offset);
+            return new ReadOnlySlice<T>(_buffer, start, length, _bufferOffset);
         }
 
         /// <summary>
@@ -154,7 +159,7 @@ namespace Avalonia.Utilities
                 throw new ArgumentOutOfRangeException(nameof(length));
             }
 
-            return new ReadOnlySlice<T>(_buffer, Start, length, _offset);
+            return new ReadOnlySlice<T>(_buffer, Start, length, _bufferOffset);
         }
 
         /// <summary>
@@ -174,7 +179,7 @@ namespace Avalonia.Utilities
                 throw new ArgumentOutOfRangeException(nameof(length));
             }
 
-            return new ReadOnlySlice<T>(_buffer, Start + length, Length - length, _offset + length);
+            return new ReadOnlySlice<T>(_buffer, Start + length, Length - length, _bufferOffset + length);
         }
 
         /// <summary>