Merge remote-tracking branch 'origin/ShapedBufferPooling' into ShapedBufferPooling

src/Avalonia.Base/Media/TextFormatting/ShapedBuffer.cs

@@ -8,7 +8,7 @@ namespace Avalonia.Media.TextFormatting
     public sealed class ShapedBuffer : IList<GlyphInfo>, IDisposable
     {
         private static readonly IComparer<GlyphInfo> s_clusterComparer = new CompareClusters();
-        private bool _rented;
+        private bool _bufferRented;
         
         public ShapedBuffer(CharacterBufferRange characterBufferRange, int bufferLength, IGlyphTypeface glyphTypeface, double fontRenderingEmSize, sbyte bidiLevel) : 
             this(characterBufferRange, 
@@ -17,7 +17,7 @@ namespace Avalonia.Media.TextFormatting
                 fontRenderingEmSize,  
                 bidiLevel)
         {
-            _rented = true;
+            _bufferRented = true;
             Length = bufferLength;
         }
 
@@ -272,7 +272,7 @@ namespace Avalonia.Media.TextFormatting
         public void Dispose()
         {
             GC.SuppressFinalize(this);
-            if (_rented)
+            if (_bufferRented)
             {
                 GlyphInfos.ReturnRent();
             }
@@ -280,7 +280,7 @@ namespace Avalonia.Media.TextFormatting
 
         ~ShapedBuffer()
         {
-            if (_rented)
+            if (_bufferRented)
             {
                 GlyphInfos.ReturnRent();
             }

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

@@ -981,9 +981,12 @@ namespace Avalonia.Media.TextFormatting
 
         public override void Dispose()
         {
-            foreach (var run in _textRuns.OfType<ShapedTextRun>())
+            for (int i = 0; i < _textRuns.Count; i++)
             {
-                run.Dispose();
+                if (_textRuns[i] is ShapedTextRun shapedTextRun)
+                {
+                    shapedTextRun.Dispose();
+                }
             }
         }
 

src/Avalonia.Controls/Presenters/TextPresenter.cs

@@ -588,6 +588,7 @@ namespace Avalonia.Controls.Presenters
 
         protected virtual void InvalidateTextLayout()
         {
+            _textLayout?.Dispose();
             _textLayout = null;
 
             InvalidateMeasure();
@@ -597,6 +598,7 @@ namespace Avalonia.Controls.Presenters
         {
             _constraint = availableSize;
 
+            _textLayout?.Dispose();
             _textLayout = null;
 
             InvalidateArrange();
@@ -622,6 +624,7 @@ namespace Avalonia.Controls.Presenters
 
             _constraint = new Size(Math.Ceiling(finalSize.Width), double.PositiveInfinity);
 
+            _textLayout?.Dispose();
             _textLayout = null;
 
             return finalSize;

src/Avalonia.Controls/TextBlock.cs

@@ -173,13 +173,7 @@ namespace Avalonia.Controls
         /// <summary>
         /// Gets the <see cref="TextLayout"/> used to render the text.
         /// </summary>
-        public TextLayout TextLayout
-        {
-            get
-            {
-                return _textLayout ??= CreateTextLayout(_text);
-            }
-        }
+        public TextLayout TextLayout => _textLayout ??= CreateTextLayout(_text);
 
         /// <summary>
         /// Gets or sets the padding to place around the <see cref="Text"/>.
@@ -648,6 +642,7 @@ namespace Avalonia.Controls
         /// </summary>
         protected void InvalidateTextLayout()
         {
+            _textLayout?.Dispose();
             _textLayout = null;
 
             InvalidateVisual();
@@ -663,6 +658,7 @@ namespace Avalonia.Controls
 
             _constraint = availableSize.Deflate(padding);
 
+            _textLayout?.Dispose();
             _textLayout = null;
 
             var inlines = Inlines;
@@ -726,6 +722,7 @@ namespace Avalonia.Controls
 
             _constraint = new Size(Math.Ceiling(finalSize.Deflate(padding).Width), double.PositiveInfinity);
 
+            _textLayout?.Dispose();
             _textLayout = null;
 
             if (HasComplexContent)

tests/Avalonia.Benchmarks/Text/HugeTextLayout.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Linq;
+using Avalonia.Controls;
 using Avalonia.Media;
 using Avalonia.Media.TextFormatting;
 using Avalonia.UnitTests;
@@ -70,6 +71,26 @@ In respect that the structure of the sufficient amount poses problems and challe
     [Benchmark]
     public TextLayout[] BuildManySmallTexts() => _manySmallStrings.Select(MakeLayout).ToArray();
 
+    [Benchmark]
+    public void VirtualizeTextBlocks()
+    {
+        var blocks = new TextBlock[10];
+        for (var i = 0; i < blocks.Length; i++)
+        {
+            blocks[i] = new TextBlock
+            {
+                Width = 120,
+                Height = 32,
+            };
+        }
+
+        for (int i = 0, j = 0; i < _manySmallStrings.Length; i++, j = j < blocks.Length - 1 ? j + 1 : 0)
+        {
+            blocks[j].Text = _manySmallStrings[i];
+            blocks[j].Measure(new Size(200, 200));
+        }
+    }
+
     private static TextLayout MakeLayout(string str)
     {
         var layout = new TextLayout(str, Typeface.Default, 12d, Brushes.Black, maxWidth: 120);