Merge branch 'master' into colorpicker-updates-1

samples/RenderDemo/MainWindow.xaml

@@ -39,6 +39,9 @@
     <TabItem Header="Custom Animator">
       <pages:CustomAnimatorPage />
     </TabItem>
+    <TabItem Header="Spring Animation">
+      <pages:SpringAnimationsPage />
+    </TabItem>
     <TabItem Header="Clipping">
       <pages:ClippingPage />
     </TabItem>

samples/RenderDemo/Pages/SpringAnimationsPage.xaml

@@ -0,0 +1,35 @@
+<UserControl 
+  xmlns="https://github.com/avaloniaui" 
+  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
+  x:Class="RenderDemo.Pages.SpringAnimationsPage"
+  MaxWidth="600">
+  <UserControl.Resources>
+    <SpringEasing x:Key="SpringEasing" Mass="1" Stiffness="2000" Damping="20" InitialVelocity="0" />
+  </UserControl.Resources>
+  <UserControl.Styles>
+    <Style Selector="Border.spring">
+      <Style.Animations>
+        <Animation Duration="0:0:0.900" 
+                   IterationCount="Infinite" 
+                   PlaybackDirection="Normal" 
+                   Easing="{DynamicResource SpringEasing}">
+          <KeyFrame Cue="0%" KeySpline="">
+            <Setter Property="TranslateTransform.X" Value="-300"/>
+          </KeyFrame>
+          <KeyFrame Cue="100%">
+            <Setter Property="TranslateTransform.X" Value="0" />
+          </KeyFrame>
+        </Animation>
+      </Style.Animations>
+    </Style>
+  </UserControl.Styles>
+  <Grid>
+    <Border Classes="spring" Background="Red" Width="50" Height="50">
+      <Border.RenderTransform>
+        <TransformGroup>
+          <TranslateTransform />
+        </TransformGroup>
+      </Border.RenderTransform>
+    </Border>
+  </Grid>
+</UserControl>

samples/RenderDemo/Pages/SpringAnimationsPage.xaml.cs

@@ -0,0 +1,17 @@
+using Avalonia.Controls;
+using Avalonia.Markup.Xaml;
+
+namespace RenderDemo.Pages;
+
+public class SpringAnimationsPage : UserControl
+{
+    public SpringAnimationsPage()
+    {
+        InitializeComponent();
+    }
+
+    private void InitializeComponent()
+    {
+        AvaloniaXamlLoader.Load(this);
+    }
+}

src/Avalonia.Base/Animation/Easings/SpringEasing.cs

@@ -0,0 +1,80 @@
+namespace Avalonia.Animation.Easings;
+
+/// <summary>
+/// Eases a <see cref="double"/> value using a user-defined spring formula.
+/// </summary>
+public class SpringEasing : Easing
+{
+    private readonly Spring _internalSpring;
+
+    /// <summary>
+    /// The spring mass.
+    /// </summary>
+    public double Mass
+    {
+        get => _internalSpring.Mass;
+        set
+        {
+            _internalSpring.Mass = value;
+        }
+    }
+
+    /// <summary>
+    /// The spring stiffness.
+    /// </summary>
+    public double Stiffness
+    {
+        get => _internalSpring.Stiffness;
+        set
+        {
+            _internalSpring.Stiffness = value;
+        }
+    }
+
+    /// <summary>
+    /// The spring damping.
+    /// </summary> 
+    public double Damping
+    {
+        get => _internalSpring.Damping;
+        set
+        {
+            _internalSpring.Damping = value;
+        }
+    }
+
+    /// <summary>
+    /// The spring initial velocity.
+    /// </summary>
+    public double InitialVelocity
+    {
+        get => _internalSpring.InitialVelocity;
+        set
+        {
+            _internalSpring.InitialVelocity = value;
+        }
+    }
+
+    public SpringEasing(double mass = 0d, double stiffness = 0d, double damping = 0d, double initialVelocity = 0d)
+    {
+        _internalSpring = new Spring();
+
+        Mass = mass;
+        Stiffness = stiffness;
+        Damping = damping;
+        InitialVelocity = initialVelocity;
+    }
+
+    public SpringEasing(Spring keySpline)
+    {
+        _internalSpring = keySpline;
+    }
+    
+    public SpringEasing()
+    {
+        _internalSpring = new Spring();
+    }
+
+    /// <inheritdoc/>
+    public override double Ease(double progress) => _internalSpring.GetSpringProgress(progress);
+}

src/Avalonia.Base/Animation/Spring.cs

@@ -0,0 +1,143 @@
+using System;
+using System.ComponentModel;
+using System.Globalization;
+using Avalonia;
+using Avalonia.Utilities;
+
+namespace Avalonia.Animation;
+
+/// <summary>
+/// Determines how an animation is used based on spring formula.
+/// </summary>
+[TypeConverter(typeof(SpringTypeConverter))]
+public class Spring
+{
+    private SpringSolver _springSolver;
+    private double _mass;
+    private double _stiffness;
+    private double _damping;
+    private double _initialVelocity;
+    private bool _isDirty;
+
+    /// <summary>
+    /// Create a <see cref="Spring"/>.
+    /// </summary>
+    public Spring()
+    {
+        _mass = 0.0;
+        _stiffness = 0.0;
+        _damping = 0.0;
+        _initialVelocity = 0.0;
+        _isDirty = true;
+    }
+
+    /// <summary>
+    /// Create a <see cref="Spring"/> with the given parameters.
+    /// </summary>
+    /// <param name="mass">The spring mass.</param>
+    /// <param name="stiffness">The spring stiffness.</param>
+    /// <param name="damping">The spring damping.</param>
+    /// <param name="initialVelocity">The spring initial velocity.</param>
+    public Spring(double mass, double stiffness, double damping, double initialVelocity)
+    {
+        _mass = mass;
+        _stiffness = stiffness;
+        _damping = damping;
+        _initialVelocity = initialVelocity;
+        _isDirty = true;
+    }
+
+    /// <summary>
+    /// Parse a <see cref="Spring"/> from a string. The string needs to contain 4 values in it.
+    /// </summary>
+    /// <param name="value">string with 4 values in it</param>
+    /// <param name="culture">culture of the string</param>
+    /// <exception cref="FormatException">Thrown if the string does not have 4 values</exception>
+    /// <returns>A <see cref="Spring"/> with the appropriate values set</returns>
+    public static Spring Parse(string value, CultureInfo? culture)
+    {
+        if (culture is null)
+        {
+            culture = CultureInfo.InvariantCulture;
+        }
+
+        using var tokenizer = new StringTokenizer(value, culture, exceptionMessage: $"Invalid Spring string: \"{value}\".");
+        return new Spring(tokenizer.ReadDouble(), tokenizer.ReadDouble(), tokenizer.ReadDouble(), tokenizer.ReadDouble());
+    }
+
+    /// <summary>
+    /// The spring mass.
+    /// </summary>
+    public double Mass
+    {
+        get => _mass;
+        set
+        {
+            _mass = value;
+            _isDirty = true;
+        }
+    }
+
+    /// <summary>
+    /// The spring stiffness.
+    /// </summary>
+    public double Stiffness
+    {
+        get => _stiffness;
+        set
+        {
+            _stiffness = value;
+            _isDirty = true;
+        }
+    }
+
+    /// <summary>
+    /// The spring damping.
+    /// </summary>
+    public double Damping
+    {
+        get => _damping;
+        set
+        {
+            _damping = value;
+            _isDirty = true;
+        }
+    }
+
+    /// <summary>
+    /// The spring initial velocity.
+    /// </summary>
+    public double InitialVelocity
+    {
+        get => _initialVelocity;
+        set
+        {
+            _initialVelocity = value;
+            _isDirty = true;
+        }
+    }
+
+    /// <summary>
+    /// Calculates spring progress from a linear progress.
+    /// </summary>
+    /// <param name="linearProgress">the linear progress</param>
+    /// <returns>The spring progress</returns>
+    public double GetSpringProgress(double linearProgress)
+    {
+        if (_isDirty)
+        {
+            Build();
+        }
+
+        return _springSolver.Solve(linearProgress);
+    }
+
+    /// <summary>
+    /// Create cached spring solver.
+    /// </summary>
+    private void Build()
+    {
+        _springSolver = new SpringSolver(_mass, _stiffness, _damping, _initialVelocity);
+        _isDirty = false;
+    }
+}

src/Avalonia.Base/Animation/SpringTypeConverter.cs

@@ -0,0 +1,21 @@
+using System;
+using System.ComponentModel;
+using System.Globalization;
+
+namespace Avalonia.Animation;
+
+/// <summary>
+/// Converts string values to <see cref="Spring"/> values.
+/// </summary>
+public class SpringTypeConverter : TypeConverter
+{
+    public override bool CanConvertFrom(ITypeDescriptorContext? context, Type sourceType)
+    {
+        return sourceType == typeof(string);
+    }
+
+    public override object ConvertFrom(ITypeDescriptorContext? context, CultureInfo? culture, object value)
+    {
+        return Spring.Parse((string)value, CultureInfo.InvariantCulture);
+    }
+}

src/Avalonia.Base/Avalonia.Base.csproj

@@ -35,8 +35,10 @@
     <InternalsVisibleTo Include="Avalonia.Skia.RenderTests, PublicKey=$(AvaloniaPublicKey)" />
     <InternalsVisibleTo Include="Avalonia.Skia.UnitTests, PublicKey=$(AvaloniaPublicKey)" />
     <InternalsVisibleTo Include="Avalonia.UnitTests, PublicKey=$(AvaloniaPublicKey)" />
+    <InternalsVisibleTo Include="Avalonia.Win32, PublicKey=$(AvaloniaPublicKey)" />
     <InternalsVisibleTo Include="Avalonia.Web.Blazor, PublicKey=$(AvaloniaPublicKey)" />
     <InternalsVisibleTo Include="Avalonia.Dialogs, PublicKey=$(AvaloniaPublicKey)" />
+    <InternalsVisibleTo Include="Avalonia.Diagnostics, PublicKey=$(AvaloniaPublicKey)"/>
     <InternalsVisibleTo Include="DynamicProxyGenAssembly2, PublicKey=0024000004800000940000000602000000240000525341310004000001000100c547cac37abd99c8db225ef2f6c8a3602f3b3606cc9891605d02baa56104f4cfc0734aa39b93bf7852f7d9266654753cc297e7d2edfe0bac1cdcf9f717241550e0a7b191195b7667bb4f64bcb8e2121380fd1d9d46ad2d92d2d15605093924cceaf74c4861eff62abf69b9291ed0a340e113be11e6a7d3113e92484cf7045cc7" />
   </ItemGroup>
 

src/Avalonia.Base/Data/Core/Plugins/ObservableStreamPlugin.cs

@@ -42,7 +42,7 @@ namespace Avalonia.Data.Core.Plugins
             if (target is IObservable<object?> result)
             {
                 return result;
-            };
+            }
 
             // If the observable returns a value type then we need to call Observable.Select on it.
             // First get the type of T in `IObservable<T>`.

src/Avalonia.Base/Input/GestureRecognizers/ScrollGestureRecognizer.cs

@@ -71,7 +71,7 @@ namespace Avalonia.Input.GestureRecognizers
             {
                 EndGesture();
                 _tracking = e.Pointer;
-                _gestureId = ScrollGestureEventArgs.GetNextFreeId();;
+                _gestureId = ScrollGestureEventArgs.GetNextFreeId();
                 _trackedRootPoint = e.GetPosition(_target);
             }
         }

src/Avalonia.Base/Input/KeyGesture.cs

@@ -96,7 +96,7 @@ namespace Avalonia.Input
 
         public override string ToString()
         {
-            var s = new StringBuilder();
+            var s = StringBuilderCache.Acquire();
 
             static void Plus(StringBuilder s)
             {
@@ -132,7 +132,7 @@ namespace Avalonia.Input
             Plus(s);
             s.Append(Key);
 
-            return s.ToString();
+            return StringBuilderCache.GetStringAndRelease(s);
         }
 
         public bool Matches(KeyEventArgs keyEvent) =>

src/Avalonia.Base/Input/PointerEventArgs.cs

@@ -65,6 +65,7 @@ namespace Avalonia.Input
                 return default;
             if (relativeTo == null)
                 return pt;
+
             return pt * _rootVisual.TransformToVisual(relativeTo) ?? default;
         }
 

src/Avalonia.Base/Input/PointerOverPreProcessor.cs

@@ -68,27 +68,29 @@ namespace Avalonia.Input
 
                 if (dirtyRect.Contains(clientPoint))
                 {
-                    SetPointerOver(pointer, _inputRoot, _inputRoot.InputHitTest(clientPoint), 0, clientPoint, PointerPointProperties.None, KeyModifiers.None);
+                    var element = pointer.Captured ?? _inputRoot.InputHitTest(clientPoint);
+                    SetPointerOver(pointer, _inputRoot, element, 0, clientPoint, PointerPointProperties.None, KeyModifiers.None);
                 }
                 else if (!_inputRoot.Bounds.Contains(clientPoint))
                 {
-                    ClearPointerOver(pointer, _inputRoot, 0, new Point(-1, -1), PointerPointProperties.None, KeyModifiers.None);
+                    ClearPointerOver(pointer, _inputRoot, 0, clientPoint, PointerPointProperties.None, KeyModifiers.None);
                 }
             }
         }
 
         private void ClearPointerOver()
         {
-            if (_lastPointer is (var pointer, var _))
+            if (_lastPointer is (var pointer, var position))
             {
-                ClearPointerOver(pointer, _inputRoot, 0, new Point(-1, -1), PointerPointProperties.None, KeyModifiers.None);
+                var clientPoint = _inputRoot.PointToClient(position);
+                ClearPointerOver(pointer, _inputRoot, 0, clientPoint, PointerPointProperties.None, KeyModifiers.None);
             }
             _lastPointer = null;
             _lastActivePointerDevice = null;
         }
 
         private void ClearPointerOver(IPointer pointer, IInputRoot root,
-            ulong timestamp, Point position, PointerPointProperties properties, KeyModifiers inputModifiers)
+            ulong timestamp, Point? position, PointerPointProperties properties, KeyModifiers inputModifiers)
         {
             var element = root.PointerOverElement;
             if (element is null)
@@ -96,11 +98,10 @@ namespace Avalonia.Input
                 return;
             }
 
-            // Do not pass rootVisual, when we have unknown (negative) position,
+            // Do not pass rootVisual, when we have unknown position,
             // so GetPosition won't return invalid values.
-            var hasPosition = position.X >= 0 && position.Y >= 0;
             var e = new PointerEventArgs(InputElement.PointerExitedEvent, element, pointer,
-                hasPosition ? root : null, hasPosition ? position : default,
+                position.HasValue ? root : null, position.HasValue ? position.Value : default,
                 timestamp, properties, inputModifiers);
 
             if (element != null && !element.IsAttachedToVisualTree)

src/Avalonia.Base/Layout/FlowLayoutAlgorithm.cs

@@ -523,7 +523,7 @@ namespace Avalonia.Layout
             {
                 firstRealizedElement = _elementManager.GetAt(0);
                 firstBounds = _elementManager.GetLayoutBoundsForRealizedIndex(0);
-                firstDataIndex = _elementManager.GetDataIndexFromRealizedRangeIndex(0);;
+                firstDataIndex = _elementManager.GetDataIndexFromRealizedRangeIndex(0);
 
                 int last = _elementManager.GetRealizedElementCount() - 1;
                 lastRealizedElement = _elementManager.GetAt(last);

src/Avalonia.Base/Logging/TraceLogSink.cs

@@ -46,7 +46,7 @@ namespace Avalonia.Logging
             object? source,
             object?[]? values)
         {
-            var result = new StringBuilder(template.Length);
+            var result = StringBuilderCache.Acquire(template.Length);
             var r = new CharacterReader(template.AsSpan());
             var i = 0;
 
@@ -89,7 +89,7 @@ namespace Avalonia.Logging
                 result.Append(')');
             }
 
-            return result.ToString();
+            return StringBuilderCache.GetStringAndRelease(result);
         }
 
         private static string Format(
@@ -98,7 +98,7 @@ namespace Avalonia.Logging
             object? source,
             object?[] v)
         {
-            var result = new StringBuilder(template.Length);
+            var result = StringBuilderCache.Acquire(template.Length);
             var r = new CharacterReader(template.AsSpan());
             var i = 0;
 

src/Avalonia.Base/Media/BoxShadow.cs

@@ -80,7 +80,7 @@ namespace Avalonia.Media
 
         public override string ToString()
         {
-            var sb = new StringBuilder();
+            var sb = StringBuilderCache.Acquire();
 
             if (IsEmpty)
             {
@@ -114,7 +114,7 @@ namespace Avalonia.Media
 
             sb.AppendFormat(" {0}", Color.ToString());
 
-            return sb.ToString();
+            return StringBuilderCache.GetStringAndRelease(sb);
         }
 
         public static unsafe BoxShadow Parse(string s)

src/Avalonia.Base/Media/BoxShadows.cs

@@ -1,7 +1,7 @@
 using System;
 using System.ComponentModel;
-using System.Text;
 using Avalonia.Animation.Animators;
+using Avalonia.Utilities;
 
 namespace Avalonia.Media
 {
@@ -45,7 +45,7 @@ namespace Avalonia.Media
 
         public override string ToString()
         {
-            var sb = new StringBuilder();
+            var sb = StringBuilderCache.Acquire();
 
             if (Count == 0)
             {
@@ -57,7 +57,7 @@ namespace Avalonia.Media
                 sb.AppendFormat("{0} ", boxShadow.ToString());
             }
 
-            return sb.ToString();
+            return StringBuilderCache.GetStringAndRelease(sb);
 
         }
 

src/Avalonia.Base/Media/Fonts/FamilyNameCollection.cs

@@ -77,7 +77,7 @@ namespace Avalonia.Media.Fonts
         /// </returns>
         public override string ToString()
         {
-            var builder = new StringBuilder();
+            var builder = StringBuilderCache.Acquire();
 
             for (var index = 0; index < Names.Count; index++)
             {
@@ -91,7 +91,7 @@ namespace Avalonia.Media.Fonts
                 builder.Append(", ");
             }
 
-            return builder.ToString();
+            return StringBuilderCache.GetStringAndRelease(builder);
         }
 
         /// <summary>

src/Avalonia.Base/Media/HslColor.cs

@@ -202,7 +202,7 @@ namespace Avalonia.Media
         /// <inheritdoc/>
         public override string ToString()
         {
-            var sb = new StringBuilder();
+            var sb = StringBuilderCache.Acquire();
 
             // Use a format similar to CSS. However:
             //   - To ensure precision is never lost, allow decimal places.
@@ -225,7 +225,7 @@ namespace Avalonia.Media
             sb.Append(A.ToString(CultureInfo.InvariantCulture));
             sb.Append(')');
 
-            return sb.ToString();
+            return StringBuilderCache.GetStringAndRelease(sb);
         }
 
         /// <summary>

src/Avalonia.Base/Media/HsvColor.cs

@@ -202,7 +202,7 @@ namespace Avalonia.Media
         /// <inheritdoc/>
         public override string ToString()
         {
-            var sb = new StringBuilder();
+            var sb = StringBuilderCache.Acquire();
 
             // Use a format similar to CSS. However:
             //   - To ensure precision is never lost, allow decimal places.
@@ -225,7 +225,7 @@ namespace Avalonia.Media
             sb.Append(A.ToString(CultureInfo.InvariantCulture));
             sb.Append(')');
 
-            return sb.ToString();
+            return StringBuilderCache.GetStringAndRelease(sb);
         }
 
         /// <summary>

src/Avalonia.Base/Media/TextTrimming.cs

@@ -8,7 +8,7 @@ namespace Avalonia.Media
     /// </summary>
     public abstract class TextTrimming
     {
-        public static char s_defaultEllipsisChar = '\u2026';
+        internal const char DefaultEllipsisChar = '\u2026';
 
         /// <summary>
         /// Text is not trimmed.
@@ -18,22 +18,22 @@ namespace Avalonia.Media
         /// <summary>
         /// Text is trimmed at a character boundary. An ellipsis (...) is drawn in place of remaining text.
         /// </summary>
-        public static TextTrimming CharacterEllipsis { get; } = new TextTrailingTrimming(s_defaultEllipsisChar, false);
+        public static TextTrimming CharacterEllipsis { get; } = new TextTrailingTrimming(DefaultEllipsisChar, false);
 
         /// <summary>
         /// Text is trimmed at a word boundary. An ellipsis (...) is drawn in place of remaining text.
         /// </summary>
-        public static TextTrimming WordEllipsis { get; } = new TextTrailingTrimming(s_defaultEllipsisChar, true);
+        public static TextTrimming WordEllipsis { get; } = new TextTrailingTrimming(DefaultEllipsisChar, true);
 
         /// <summary>
         /// Text is trimmed after a given prefix length. An ellipsis (...) is drawn in between prefix and suffix and represents remaining text.
         /// </summary>
-        public static TextTrimming PrefixCharacterEllipsis { get; } = new TextLeadingPrefixTrimming(s_defaultEllipsisChar, 8);
+        public static TextTrimming PrefixCharacterEllipsis { get; } = new TextLeadingPrefixTrimming(DefaultEllipsisChar, 8);
 
         /// <summary>
         /// Text is trimmed at a character boundary starting from the beginning. An ellipsis (...) is drawn in place of remaining text.
         /// </summary>
-        public static TextTrimming LeadingCharacterEllipsis { get; } = new TextLeadingPrefixTrimming(s_defaultEllipsisChar, 0);
+        public static TextTrimming LeadingCharacterEllipsis { get; } = new TextLeadingPrefixTrimming(DefaultEllipsisChar, 0);
 
         /// <summary>
         /// Creates properties that will be used for collapsing lines of text.

src/Avalonia.Base/Media/UnicodeRange.cs

@@ -9,7 +9,7 @@ namespace Avalonia.Media
     /// </summary>
     public readonly struct UnicodeRange
     {
-        public static UnicodeRange Default = Parse("0-10FFFD");
+        public readonly static UnicodeRange Default = Parse("0-10FFFD");
 
         private readonly UnicodeRangeSegment _single;
         private readonly IReadOnlyList<UnicodeRangeSegment>? _segments = null;

src/Avalonia.Base/Rendering/Composition/CompositingRenderer.cs

@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Numerics;
 using System.Runtime.InteropServices;
+using System.Threading.Tasks;
 using Avalonia.Collections;
 using Avalonia.Collections.Pooled;
 using Avalonia.Media;
@@ -27,8 +28,7 @@ public class CompositingRenderer : IRendererWithCompositor
     private HashSet<Visual> _dirty = new();
     private HashSet<Visual> _recalculateChildren = new();
     private bool _queuedUpdate;
-    private Action _update;
+    private Action<Task> _update;
-    private Action _invalidateScene;
     private bool _updating;
 
     internal CompositionTarget CompositionTarget;
@@ -47,7 +47,6 @@ public class CompositingRenderer : IRendererWithCompositor
         CompositionTarget = compositor.CreateCompositionTarget(root.CreateRenderTarget);
         CompositionTarget.Root = ((Visual)root!.VisualRoot!).AttachToCompositor(compositor);
         _update = Update;
-        _invalidateScene = InvalidateScene;
     }
 
     /// <inheritdoc/>
@@ -72,7 +71,7 @@ public class CompositingRenderer : IRendererWithCompositor
         if(_queuedUpdate)
             return;
         _queuedUpdate = true;
-        _compositor.InvokeWhenReadyForNextCommit(_update);
+        _compositor.InvokeBeforeNextCommit(_update);
     }
     
     /// <inheritdoc/>
@@ -151,12 +150,6 @@ public class CompositingRenderer : IRendererWithCompositor
         if (compositionChildren.Count == visualChildren.Count)
         {
             bool mismatch = false;
-            if (v.HasNonUniformZIndexChildren)
-            {
-                
-                
-            }
-
             if (sortedChildren != null)
                 for (var c = 0; c < visualChildren.Count; c++)
                 {
@@ -202,9 +195,6 @@ public class CompositingRenderer : IRendererWithCompositor
             }
     }
 
-    private void InvalidateScene() =>
-        SceneInvalidated?.Invoke(this, new SceneInvalidatedEventArgs(_root, new Rect(_root.ClientSize)));
-
     private void UpdateCore()
     {
         _queuedUpdate = false;
@@ -252,10 +242,15 @@ public class CompositingRenderer : IRendererWithCompositor
         _recalculateChildren.Clear();
         CompositionTarget.Size = _root.ClientSize;
         CompositionTarget.Scaling = _root.RenderScaling;
-        Compositor.InvokeOnNextCommit(_invalidateScene);
     }
 
-    private void Update()
+    private async void TriggerSceneInvalidatedOnBatchCompletion(Task batchCompletion)
+    {
+        await batchCompletion;
+        SceneInvalidated?.Invoke(this, new SceneInvalidatedEventArgs(_root, new Rect(_root.ClientSize)));
+    }
+    
+    private void Update(Task batchCompletion)
     {
         if(_updating)
             return;
@@ -276,10 +271,10 @@ public class CompositingRenderer : IRendererWithCompositor
 
     public void Paint(Rect rect)
     {
-        Update();
+        QueueUpdate();
         CompositionTarget.RequestRedraw();
         if(RenderOnlyOnRenderThread && Compositor.Loop.RunsInBackground)
-            Compositor.RequestCommitAsync().Wait();
+            Compositor.Commit().Wait();
         else
             CompositionTarget.ImmediateUIThreadRender();
     }
@@ -299,7 +294,7 @@ public class CompositingRenderer : IRendererWithCompositor
         // Wait for the composition batch to be applied and rendered to guarantee that
         // render target is not used anymore and can be safely disposed
         if (Compositor.Loop.RunsInBackground)
-            _compositor.RequestCommitAsync().Wait();
+            _compositor.Commit().Wait();
     }
 
     /// <summary>

src/Avalonia.Base/Rendering/Composition/CompositionTarget.cs

@@ -129,7 +129,7 @@ namespace Avalonia.Rendering.Composition
         /// </summary>
         internal void ImmediateUIThreadRender()
         {
-            Compositor.RequestCommitAsync();
+            Compositor.Commit();
             Compositor.Server.Render();
         }
     }

src/Avalonia.Base/Rendering/Composition/Compositor.Factories.cs

@@ -0,0 +1,32 @@
+using System;
+using Avalonia.Platform;
+using Avalonia.Rendering.Composition.Animations;
+using Avalonia.Rendering.Composition.Server;
+
+namespace Avalonia.Rendering.Composition;
+
+public partial class Compositor
+{
+    /// <summary>
+    /// Creates a new CompositionTarget
+    /// </summary>
+    /// <param name="renderTargetFactory">A factory method to create IRenderTarget to be called from the render thread</param>
+    /// <returns></returns>
+    public CompositionTarget CreateCompositionTarget(Func<IRenderTarget> renderTargetFactory)
+    {
+        return new CompositionTarget(this, new ServerCompositionTarget(_server, renderTargetFactory));
+    }
+    
+    public CompositionContainerVisual CreateContainerVisual() => new(this, new ServerCompositionContainerVisual(_server));
+        
+    public ExpressionAnimation CreateExpressionAnimation() => new ExpressionAnimation(this);
+
+    public ExpressionAnimation CreateExpressionAnimation(string expression) => new ExpressionAnimation(this)
+    {
+        Expression = expression
+    };
+
+    public ImplicitAnimationCollection CreateImplicitAnimationCollection() => new ImplicitAnimationCollection(this);
+
+    public CompositionAnimationGroup CreateAnimationGroup() => new CompositionAnimationGroup(this);
+}

src/Avalonia.Base/Rendering/Composition/Compositor.cs

@@ -10,6 +10,7 @@ using Avalonia.Rendering.Composition.Animations;
 using Avalonia.Rendering.Composition.Server;
 using Avalonia.Rendering.Composition.Transport;
 using Avalonia.Threading;
+using Avalonia.Utilities;
 
 
 // Special license applies <see href="https://raw.githubusercontent.com/AvaloniaUI/Avalonia/master/src/Avalonia.Base/Rendering/Composition/License.md">License.md</see>
@@ -24,16 +25,18 @@ namespace Avalonia.Rendering.Composition
     {
         internal IRenderLoop Loop { get; }
         private ServerCompositor _server;
-        private bool _implicitBatchCommitQueued;
+        private TaskCompletionSource<int>? _nextCommit;
-        private Action _implicitBatchCommit;
+        private Action _commit;
         private BatchStreamObjectPool<object?> _batchObjectPool = new();
         private BatchStreamMemoryPool _batchMemoryPool = new();
         private List<CompositionObject> _objectsForSerialization = new();
+        private Queue<Action<Task>> _invokeBeforeCommit = new();
         internal ServerCompositor Server => _server;
+        private Task? _pendingBatch;
+        private readonly object _pendingBatchLock = new();
+
         internal IEasing DefaultEasing { get; }
-        private List<Action>? _invokeOnNextCommit;
+        
-        private readonly Stack<List<Action>> _invokeListPool = new();
-        private Task? _lastBatchCompleted;
 
         /// <summary>
         /// Creates a new compositor on a specified render loop that would use a particular GPU
@@ -44,21 +47,15 @@ namespace Avalonia.Rendering.Composition
         {
             Loop = loop;
             _server = new ServerCompositor(loop, gpu, _batchObjectPool, _batchMemoryPool);
-            _implicitBatchCommit = ImplicitBatchCommit;
+            _commit = () =>
+            {
+                Console.WriteLine("Dispatcher:Commit");
+                Commit();
+            };
 
             DefaultEasing = new CubicBezierEasing(new Point(0.25f, 0.1f), new Point(0.25f, 1f));
         }
 
-        /// <summary>
-        /// Creates a new CompositionTarget
-        /// </summary>
-        /// <param name="renderTargetFactory">A factory method to create IRenderTarget to be called from the render thread</param>
-        /// <returns></returns>
-        public CompositionTarget CreateCompositionTarget(Func<IRenderTarget> renderTargetFactory)
-        {
-            return new CompositionTarget(this, new ServerCompositionTarget(_server, renderTargetFactory));
-        }
-
         /// <summary>
         /// Requests pending changes in the composition objects to be serialized and sent to the render thread
         /// </summary>
@@ -66,7 +63,35 @@ namespace Avalonia.Rendering.Composition
         public Task RequestCommitAsync()
         {
             Dispatcher.UIThread.VerifyAccess();
-            var batch = new Batch();
+            if (_nextCommit == null)
+            {
+                _nextCommit = new TaskCompletionSource<int>();
+                var pending = _pendingBatch;
+                if (pending != null)
+                {
+                    pending.ContinueWith(_ =>
+                    {
+                        Dispatcher.UIThread.Post(_commit, DispatcherPriority.Composition);
+                    });
+                }
+                else
+                    Dispatcher.UIThread.Post(_commit, DispatcherPriority.Composition);
+            }
+
+            return _nextCommit.Task;
+        }
+        
+        internal Task Commit()
+        {
+            Dispatcher.UIThread.VerifyAccess();
+            using var noPump = NonPumpingLockHelper.Use();
+            
+            _nextCommit ??= new TaskCompletionSource<int>();
+
+            while (_invokeBeforeCommit.Count > 0)
+                _invokeBeforeCommit.Dequeue()(_nextCommit.Task);
+            
+            var batch = new Batch(_nextCommit);
             
             using (var writer = new BatchStreamWriter(batch.Changes, _batchMemoryPool, _batchObjectPool))
             {
@@ -84,71 +109,36 @@ namespace Avalonia.Rendering.Composition
             
             batch.CommitedAt = Server.Clock.Elapsed;
             _server.EnqueueBatch(batch);
-            if (_invokeOnNextCommit != null) 
-                ScheduleCommitCallbacks(batch.Completed);
             
-            return _lastBatchCompleted = batch.Completed;
+            lock (_pendingBatchLock)
-        }
+            {
-
+                _pendingBatch = _nextCommit.Task;
-        async void ScheduleCommitCallbacks(Task task)
+                _pendingBatch.ContinueWith(t =>
-        {
+                {
-            var list = _invokeOnNextCommit;
+                    lock (_pendingBatchLock)
-            _invokeOnNextCommit = null;
+                    {
-            await task;
+                        if (_pendingBatch == t)
-            foreach (var i in list!)
+                            _pendingBatch = null;
-                i();
+                    }
-            list.Clear();
+                }, TaskContinuationOptions.ExecuteSynchronously);
-            _invokeListPool.Push(list);
+                _nextCommit = null;
-        }
+                
-
+                return _pendingBatch;
-        public CompositionContainerVisual CreateContainerVisual() => new(this, new ServerCompositionContainerVisual(_server));
+            }
-        
-        public ExpressionAnimation CreateExpressionAnimation() => new ExpressionAnimation(this);
-
-        public ExpressionAnimation CreateExpressionAnimation(string expression) => new ExpressionAnimation(this)
-        {
-            Expression = expression
-        };
-
-        public ImplicitAnimationCollection CreateImplicitAnimationCollection() => new ImplicitAnimationCollection(this);
-
-        public CompositionAnimationGroup CreateAnimationGroup() => new CompositionAnimationGroup(this);
-        
-        private void QueueImplicitBatchCommit()
-        {
-            if(_implicitBatchCommitQueued)
-                return;
-            _implicitBatchCommitQueued = true;
-            Dispatcher.UIThread.Post(_implicitBatchCommit, DispatcherPriority.CompositionBatch);
-        }
-
-        private void ImplicitBatchCommit()
-        {
-            _implicitBatchCommitQueued = false;
-            RequestCommitAsync();
         }
 
         internal void RegisterForSerialization(CompositionObject compositionObject)
         {
             Dispatcher.UIThread.VerifyAccess();
             _objectsForSerialization.Add(compositionObject);
-            QueueImplicitBatchCommit();
+            RequestCommitAsync();
-        }
-
-        internal void InvokeOnNextCommit(Action action)
-        {
-            _invokeOnNextCommit ??= _invokeListPool.Count > 0 ? _invokeListPool.Pop() : new();
-            _invokeOnNextCommit.Add(action);
         }
 
-        public void InvokeWhenReadyForNextCommit(Action action)
+        internal void InvokeBeforeNextCommit(Action<Task> action)
         {
-            if (_lastBatchCompleted == null || _lastBatchCompleted.IsCompleted)
+            Dispatcher.UIThread.VerifyAccess();
-                Dispatcher.UIThread.Post(action, DispatcherPriority.Composition);
+            _invokeBeforeCommit.Enqueue(action);
-            else
+            RequestCommitAsync();
-                _lastBatchCompleted.ContinueWith(
-                    static (_, state) => Dispatcher.UIThread.Post((Action)state!, DispatcherPriority.Composition),
-                    action);
         }
     }
 }

src/Avalonia.Base/Rendering/Composition/Transport/Batch.cs

@@ -15,16 +15,19 @@ namespace Avalonia.Rendering.Composition.Transport
     {
         private static long _nextSequenceId = 1;
         private static ConcurrentBag<BatchStreamData> _pool = new();
+        private readonly TaskCompletionSource<int>? _tcs;
         public long SequenceId { get; }
         
-        public Batch()
+        public Batch(TaskCompletionSource<int>? tcs)
         {
+            _tcs = tcs;
             SequenceId = Interlocked.Increment(ref _nextSequenceId);
             if (!_pool.TryTake(out var lst))
                 lst = new BatchStreamData();
             Changes = lst;
         }
-        private TaskCompletionSource<int> _tcs = new TaskCompletionSource<int>();
+
+        
         public BatchStreamData Changes { get; private set; }
         public TimeSpan CommitedAt { get; set; }
         
@@ -33,9 +36,8 @@ namespace Avalonia.Rendering.Composition.Transport
             _pool.Add(Changes);
             Changes = null!;
 
-            _tcs.TrySetResult(0);
+            _tcs?.TrySetResult(0);
         }
 
-        public Task Completed => _tcs.Task;
     }
 }

src/Avalonia.Base/Styling/NthChildSelector.cs

@@ -1,8 +1,8 @@
 #nullable enable
 using System;
-using System.Text;
 using Avalonia.LogicalTree;
 using Avalonia.Styling.Activators;
+using Avalonia.Utilities;
 
 namespace Avalonia.Styling
 {
@@ -110,7 +110,8 @@ namespace Avalonia.Styling
         public override string ToString()
         {
             var expectedCapacity = NthLastChildSelectorName.Length + 8;
-            var stringBuilder = new StringBuilder(_previous?.ToString(), expectedCapacity);
+            var stringBuilder =  StringBuilderCache.Acquire(expectedCapacity);
+            stringBuilder.Append(_previous?.ToString());
             
             stringBuilder.Append(':');
             stringBuilder.Append(_reversed ? NthLastChildSelectorName : NthChildSelectorName);
@@ -140,7 +141,7 @@ namespace Avalonia.Styling
 
             stringBuilder.Append(')');
 
-            return stringBuilder.ToString();
+            return StringBuilderCache.GetStringAndRelease(stringBuilder);
         }
     }
 }

src/Avalonia.Base/Styling/PropertyEqualsSelector.cs

@@ -1,8 +1,8 @@
 using System;
 using System.ComponentModel;
 using System.Globalization;
-using System.Text;
 using Avalonia.Styling.Activators;
+using Avalonia.Utilities;
 
 #nullable enable
 
@@ -42,7 +42,7 @@ namespace Avalonia.Styling
         {
             if (_selectorString == null)
             {
-                var builder = new StringBuilder();
+                var builder = StringBuilderCache.Acquire();
 
                 if (_previous != null)
                 {
@@ -67,7 +67,7 @@ namespace Avalonia.Styling
                 builder.Append(_value ?? string.Empty);
                 builder.Append(']');
 
-                _selectorString = builder.ToString();
+                _selectorString = StringBuilderCache.GetStringAndRelease(builder);
             }
 
             return _selectorString;

src/Avalonia.Base/Styling/TypeNameAndClassSelector.cs

@@ -1,8 +1,8 @@
 using System;
 using System.Collections.Generic;
-using System.Text;
 using Avalonia.Controls;
 using Avalonia.Styling.Activators;
+using Avalonia.Utilities;
 
 #nullable enable
 
@@ -145,7 +145,7 @@ namespace Avalonia.Styling
 
         private string BuildSelectorString()
         {
-            var builder = new StringBuilder();
+            var builder = StringBuilderCache.Acquire();
 
             if (_previous != null)
             {
@@ -185,7 +185,7 @@ namespace Avalonia.Styling
                 }
             }
 
-            return builder.ToString();
+            return StringBuilderCache.GetStringAndRelease(builder);
         }
     }
 }

src/Avalonia.Base/Threading/DispatcherPriority.cs

@@ -61,21 +61,16 @@ namespace Avalonia.Threading
         /// The job will be processed with the same priority as render.
         /// </summary>
         public static readonly DispatcherPriority Render = new(5);
-
-        /// <summary>
-        /// The job will be processed with the same priority as composition batch commit.
-        /// </summary>
-        public static readonly DispatcherPriority CompositionBatch = new(6);
         
         /// <summary>
         /// The job will be processed with the same priority as composition updates.
         /// </summary>
-        public static readonly DispatcherPriority Composition = new(7);
+        public static readonly DispatcherPriority Composition = new(6);
         
         /// <summary>
         /// The job will be processed with the same priority as render.
         /// </summary>
-        public static readonly DispatcherPriority Layout = new(8);
+        public static readonly DispatcherPriority Layout = new(7);
 
         /// <summary>
         /// The job will be processed with the same priority as data binding.
@@ -85,7 +80,7 @@ namespace Avalonia.Threading
         /// <summary>
         /// The job will be processed before other asynchronous operations.
         /// </summary>
-        public static readonly DispatcherPriority Send = new(9);
+        public static readonly DispatcherPriority Send = new(8);
 
         /// <summary>
         /// Maximum possible priority

src/Avalonia.Base/Utilities/IWeakSubscriber.cs

@@ -3,7 +3,7 @@ using System;
 namespace Avalonia.Utilities
 {
     /// <summary>
-    /// Defines a listener to a event subscribed vis the <see cref="WeakSubscriptionManager"/>.
+    /// Defines a listener to a event subscribed vis the <see cref="WeakObservable"/>.
     /// </summary>
     /// <typeparam name="T">The type of the event arguments.</typeparam>
     public interface IWeakSubscriber<T> where T : EventArgs

src/Avalonia.Base/Utilities/SpringSolver.cs

@@ -0,0 +1,121 @@
+// Ported from:
+// https://svn.webkit.org/repository/webkit/trunk/Source/WebCore/platform/graphics/SpringSolver.h
+/*
+ * Copyright (C) 2016 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
+ * THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+using System;
+
+namespace Avalonia.Utilities;
+
+internal struct SpringSolver 
+{
+    private double m_w0;
+    private double m_zeta;
+    private double m_wd;
+    private double m_A;
+    private double m_B;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="period">The time period.</param>
+    /// <param name="zeta">The damping ratio.</param>
+    /// <param name="initialVelocity"></param>
+    public SpringSolver(TimeSpan period, double zeta, double initialVelocity) 
+        : this(
+            2 * Math.PI / period.TotalSeconds, 
+            zeta, 
+            initialVelocity)
+    {
+        // T is time period [s]
+        // T = (2*PI / sqrt(k)) * sqrt(m)
+
+        // ωn is natural frequency of the system [Hz] [1/s]
+        // ωn = 2*PI / T
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="m">The mass of the oscillating body.</param>
+    /// <param name="k">The stiffness of the oscillated body (spring constant).</param>
+    /// <param name="c">The actual damping.</param>
+    /// <param name="initialVelocity">The initial velocity.</param>
+    public SpringSolver(double m, double k, double c, double initialVelocity)
+        : this(
+            Math.Sqrt(k / m), // ωn
+            c / (2 * Math.Sqrt(k * m)), // c / Cc
+            initialVelocity)
+    {
+        // ωn is natural frequency of the system [Hz] [1/s]
+        // ωn = sqrt(k / m)
+
+        // Cc is critical damping coefficient
+        // Cc = 2 * Sqrt(k * m)
+        // Cc = 2 * m * wn
+        // Cc = 2 * m * Sqrt(k / m)
+
+        // ζ is damping ratio (Greek letter zeta)
+        // ζ = m_zeta = c / Cc
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="ωn">The the natural frequency of the system [rad/s].</param>
+    /// <param name="zeta">The damping ratio.</param>
+    /// <param name="initialVelocity"></param>
+    public SpringSolver(double ωn, double zeta, double initialVelocity)
+    {
+        m_w0 = ωn;
+        m_zeta = zeta;
+
+        if (m_zeta < 1) {
+            // Under-damped.
+            m_wd = m_w0 * Math.Sqrt(1 - m_zeta * m_zeta);
+            m_A = 1;
+            m_B = (m_zeta * m_w0 + -initialVelocity) / m_wd;
+        } else {
+            // Critically damped (ignoring over-damped case for now).
+            m_A = 1;
+            m_B = -initialVelocity + m_w0;
+            m_wd = 0;
+        }
+    }
+
+    public readonly double Solve(double t)
+    {
+        if (m_zeta < 1) {
+            // Under-damped
+            t = Math.Exp(-t * m_zeta * m_w0) * (m_A * Math.Cos(m_wd * t) + m_B * Math.Sin(m_wd * t));
+        } else {
+            // Critically damped (ignoring over-damped case for now).
+            t = (m_A + m_B * t) * Math.Exp(-t * m_w0);
+        }
+
+        // Map range from [1..0] to [0..1].
+        return 1 - t;
+    }
+}

src/Avalonia.Base/Utilities/StringBuilderCache.cs

@@ -0,0 +1,68 @@
+// This file is imported from dotnet/runtime
+// Source Link: https://github.com/dotnet/runtime/blob/e63d21947e734db2da5093510a6636b5b7fb45b5/src/libraries/Common/src/System/Text/StringBuilderCache.cs
+// Commit: a9c5ead on Feb 10, 2021, https://github.com/dotnet/runtime/commit/a9c5eadd951dcba73167f72cc624eb790573663a
+// 
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.Text;
+
+namespace Avalonia.Utilities;
+
+// <summary>Provide a cached reusable instance of stringbuilder per thread.</summary>
+internal static class StringBuilderCache
+{
+    // The value 360 was chosen in discussion with performance experts as a compromise between using
+    // as little memory per thread as possible and still covering a large part of short-lived
+    // StringBuilder creations on the startup path of VS designers.
+    internal const int MaxBuilderSize = 360;
+    private const int DefaultCapacity = 16; // == StringBuilder.DefaultCapacity
+
+    // WARNING: We allow diagnostic tools to directly inspect this member (t_cachedInstance).
+    // See https://github.com/dotnet/corert/blob/master/Documentation/design-docs/diagnostics/diagnostics-tools-contract.md for more details.
+    // Please do not change the type, the name, or the semantic usage of this member without understanding the implication for tools.
+    // Get in touch with the diagnostics team if you have questions.
+    [ThreadStatic]
+    private static StringBuilder? t_cachedInstance;
+
+    /// <summary>Get a StringBuilder for the specified capacity.</summary>
+    /// <remarks>If a StringBuilder of an appropriate size is cached, it will be returned and the cache emptied.</remarks>
+    public static StringBuilder Acquire(int capacity = DefaultCapacity)
+    {
+        if (capacity <= MaxBuilderSize)
+        {
+            StringBuilder? sb = t_cachedInstance;
+            if (sb != null)
+            {
+                // Avoid stringbuilder block fragmentation by getting a new StringBuilder
+                // when the requested size is larger than the current capacity
+                if (capacity <= sb.Capacity)
+                {
+                    t_cachedInstance = null;
+                    sb.Clear();
+                    return sb;
+                }
+            }
+        }
+
+        return new StringBuilder(capacity);
+    }
+
+    /// <summary>Place the specified builder in the cache if it is not too big.</summary>
+    public static void Release(StringBuilder sb)
+    {
+        if (sb.Capacity <= MaxBuilderSize)
+        {
+            t_cachedInstance = sb;
+        }
+    }
+
+    /// <summary>ToString() the stringbuilder, Release it to the cache, and return the resulting string.</summary>
+    public static string GetStringAndRelease(StringBuilder sb)
+    {
+        string result = sb.ToString();
+        Release(sb);
+        return result;
+    }
+}

src/Avalonia.Build.Tasks/Avalonia.Build.Tasks.csproj

@@ -50,6 +50,7 @@
       <Compile Include="../Avalonia.Base/Utilities/MathUtilities.cs">
         <Link>Markup/%(RecursiveDir)%(FileName)%(Extension)</Link>
       </Compile>
+      <Compile Include="..\Avalonia.Base\Utilities\StringBuilderCache.cs" Link="Utilities\StringBuilderCache.cs" />
       <Compile Include="..\Markup\Avalonia.Markup\Markup\Parsers\ArgumentListParser.cs">
         <Link>Markup/%(RecursiveDir)%(FileName)%(Extension)</Link>
       </Compile>

src/Avalonia.Controls.ColorPicker/Helpers/ColorHelper.cs

@@ -2,7 +2,7 @@
 using System.Globalization;
 using System.Collections.Generic;
 using Avalonia.Media;
-using System.Text;
+using Avalonia.Utilities;
 
 namespace Avalonia.Controls.Primitives
 {
@@ -113,7 +113,7 @@ namespace Avalonia.Controls.Primitives
             // Cache results for next time as well
             if (closestKnownColor != KnownColor.None)
             {
-                StringBuilder sb = new StringBuilder(); 
+                var sb = StringBuilderCache.Acquire();
                 string name = closestKnownColor.ToString();
 
                 // Add spaces converting PascalCase to human-readable names
@@ -128,7 +128,7 @@ namespace Avalonia.Controls.Primitives
                     sb.Append(name[i]);
                 }
 
-                string displayName = sb.ToString();
+                string displayName = StringBuilderCache.GetStringAndRelease(sb);
 
                 lock (cacheMutex)
                 {

src/Avalonia.Controls.DataGrid/DataGrid.cs

@@ -6020,7 +6020,7 @@ namespace Avalonia.Controls
         /// <returns>The formatted string.</returns>
         private string FormatClipboardContent(DataGridRowClipboardEventArgs e)
         {
-            var text = new StringBuilder();
+            var text = StringBuilderCache.Acquire();
             var clipboardRowContent = e.ClipboardRowContent;
             var numberOfItem = clipboardRowContent.Count;
             for (int cellIndex = 0; cellIndex < numberOfItem; cellIndex++)
@@ -6037,7 +6037,7 @@ namespace Avalonia.Controls
                     text.Append('\n');
                 }
             }
-            return text.ToString();
+            return StringBuilderCache.GetStringAndRelease(text);
         }
 
         /// <summary>
@@ -6052,7 +6052,7 @@ namespace Avalonia.Controls
 
             if (ctrl && !shift && !alt && ClipboardCopyMode != DataGridClipboardCopyMode.None && SelectedItems.Count > 0)
             {
-                StringBuilder textBuilder = new StringBuilder();
+                var textBuilder = StringBuilderCache.Acquire();
 
                 if (ClipboardCopyMode == DataGridClipboardCopyMode.IncludeHeader)
                 {
@@ -6078,7 +6078,7 @@ namespace Avalonia.Controls
                     textBuilder.Append(FormatClipboardContent(itemArgs));
                 }
 
-                string text = textBuilder.ToString();
+                string text = StringBuilderCache.GetStringAndRelease(textBuilder);
 
                 if (!string.IsNullOrEmpty(text))
                 {

src/Avalonia.Controls/Converters/PlatformKeyGestureConverter.cs

@@ -4,6 +4,7 @@ using System.Runtime.InteropServices;
 using System.Text;
 using Avalonia.Data.Converters;
 using Avalonia.Input;
+using Avalonia.Utilities;
 
 namespace Avalonia.Controls.Converters
 {
@@ -62,7 +63,7 @@ namespace Avalonia.Controls.Converters
 
         private static string ToString(KeyGesture gesture, string meta)
         {
-            var s = new StringBuilder();
+            var s = StringBuilderCache.Acquire();
 
             static void Plus(StringBuilder s)
             {
@@ -98,12 +99,12 @@ namespace Avalonia.Controls.Converters
             Plus(s);
             s.Append(ToString(gesture.Key));
 
-            return s.ToString();
+            return StringBuilderCache.GetStringAndRelease(s);
         }
 
         private static string ToOSXString(KeyGesture gesture)
         {
-            var s = new StringBuilder();
+            var s = StringBuilderCache.Acquire();
 
             if (gesture.KeyModifiers.HasAllFlags(KeyModifiers.Control))
             {
@@ -127,7 +128,7 @@ namespace Avalonia.Controls.Converters
 
             s.Append(ToOSXString(gesture.Key));
 
-            return s.ToString();
+            return StringBuilderCache.GetStringAndRelease(s);
         }
 
         private static string ToString(Key key)

src/Avalonia.Controls/Documents/InlineCollection.cs

@@ -1,8 +1,8 @@
 using System;
-using System.Text;
 using Avalonia.Collections;
 using Avalonia.LogicalTree;
 using Avalonia.Metadata;
+using Avalonia.Utilities;
 
 namespace Avalonia.Controls.Documents
 {
@@ -70,14 +70,14 @@ namespace Avalonia.Controls.Documents
         {
             get
             {
-                var builder = new StringBuilder();
+                var builder = StringBuilderCache.Acquire();
 
                 foreach (var inline in this)
                 {
                     inline.AppendText(builder);
                 }
 
-                return builder.ToString();
+                return StringBuilderCache.GetStringAndRelease(builder);
             }
 
         }

src/Avalonia.Controls/Window.cs

@@ -378,8 +378,6 @@ namespace Avalonia.Controls
 
         /// <summary>
         /// Enables or disables resizing of the window.
-        /// Note that if <see cref="HasSystemDecorations"/> is set to False then this property
-        /// has no effect and should be treated as a recommendation for the user setting HasSystemDecorations.
         /// </summary>
         public bool CanResize
         {

src/Avalonia.DesignerSupport/Remote/HtmlTransport/webapp/build.js

@@ -0,0 +1,28 @@
+import { build } from 'esbuild';
+import htmlPlugin from '@chialab/esbuild-plugin-html';
+import { compress } from 'esbuild-plugin-compress';
+
+build({
+    entryPoints: ['src/index.html'],
+    chunkNames: '[name]-[hash]',
+    logLevel: "warning",
+    outdir: "./build",
+    bundle: true,
+    treeShaking: true,
+    minify: true,
+    write: false,
+    format: "esm",
+    target: "es6",
+    platform: "browser",
+    sourcemap: "linked",
+    loader: {".ts": "tsx"},
+    plugins: [
+        htmlPlugin(),
+        compress({
+            brotli: false,
+            gzip: true
+        })
+    ]
+  })
+  .then(() => console.log("⚡ Done"))
+  .catch(() => process.exit(1));

src/Avalonia.DesignerSupport/Remote/HtmlTransport/webapp/package.json

@@ -1,34 +1,16 @@
 {
-  "name": "simple",
+  "name": "previewer",
-  "version": "1.0.0",
-  "description": "",
-  "main": "index.js",
   "scripts": {
-    "webpack-ver": "cross-env NODE_ENV=production webpack --version",
+    "predist": "tsc -noEmit",
-    "dist": "cross-env NODE_ENV=production webpack",
+    "dist": "node build.js"
-    "watch": "cross-env NODE_ENV=development webpack --watch"
   },
-  "author": "",
-  "license": "ISC",
   "devDependencies": {
-    "clean-webpack-plugin": "^4.0.0",
+    "@chialab/esbuild-plugin-html": "^0.17.0",
-    "compression-webpack-plugin": "^9.2.0",
+    "esbuild": "^0.14.54",
-    "cross-env": "^7.0.3",
+    "esbuild-plugin-compress": "^0.4.0",
-    "css-loader": "^6.5.1",
+    "typescript": "^4.7.4"
-    "file-loader": "^6.2.0",
-    "html-webpack-plugin": "^5.5.0",
-    "mini-css-extract-plugin": "^2.5.3",
-    "source-map-loader": "^3.0.1",
-    "style-loader": "^3.3.1",
-    "to-string-loader": "^1.2.0",
-    "ts-loader": "^9.2.6",
-    "tsconfig-paths-webpack-plugin": "^3.5.2",
-    "typescript": "^4.5.5",
-    "url-loader": "^4.1.1",
-    "webpack": "^5.68.0",
-    "webpack-cli": "^4.9.2",
-    "webpack-livereload-plugin": "^3.0.2"
   },
+  "type": "module",
   "dependencies": {
     "@types/react": "^17.0.38",
     "@types/react-dom": "^17.0.11",

src/Avalonia.DesignerSupport/Remote/HtmlTransport/webapp/src/index.html

@@ -1,14 +1,15 @@
 <!DOCTYPE html>
 <html>
+
 <head>
     <meta charset="UTF-8">
     <title>Avalonia XAML previewer web edition</title>
 </head>
-
 <body>
-<div id="app">
+    <div id="app">
-    <center>Loading...</center>
+        <center>Loading...</center>
-</div>
+    </div>
-<noscript>JavaScript is required</noscript>
+    <noscript>JavaScript is required</noscript>
+    <script src="index.tsx"></script>
 </body>
-</html>
+</html>

src/Avalonia.DesignerSupport/Remote/HtmlTransport/webapp/tsconfig.json

@@ -2,7 +2,7 @@
   "compilerOptions": {
     "outDir": "build/dist",
     "module": "esnext",
-    "target": "es5",
+    "target": "es6",
     "lib": ["es6", "dom"],
     "sourceMap": true,
     "allowJs": true,
@@ -25,11 +25,6 @@
   "include": ["./src/**/*"],
   "exclude": [
     "node_modules",
-    "build",
+    "build"
-    "scripts",
-    "acceptance-tests",
-    "webpack",
-    "jest",
-    "src/setupTests.ts"
   ]
 }

src/Avalonia.DesignerSupport/Remote/HtmlTransport/webapp/webpack.config.js

@@ -1,116 +0,0 @@
-const webpack = require('webpack');
-const path = require('path');
-const LiveReloadPlugin = require('webpack-livereload-plugin');
-const HtmlWebpackPlugin = require('html-webpack-plugin');
-const CompressionPlugin = require('compression-webpack-plugin');
-const { CleanWebpackPlugin } = require('clean-webpack-plugin');
-const MiniCssExtractPlugin = require("mini-css-extract-plugin");
-const TsconfigPathsPlugin = require('tsconfig-paths-webpack-plugin');
-const prod = process.env.NODE_ENV == 'production';
-
-class Printer {
-    apply(compiler) {
-        compiler.hooks.afterEmit.tap("Printer", ()=> console.log("Build completed at " + new Date().toString()));
-        compiler.hooks.watchRun.tap("Printer", ()=> console.log("Watch triggered at " + new Date().toString()));
-    }
-}
-
-const config = {
-    stats: {
-        errorDetails: true
-    },
-    entry: {
-            bundle: './src/index.tsx'
-        },
-    output: {
-        path: path.resolve(__dirname, 'build'),
-        publicPath: '/',
-        filename: '[name].[chunkhash].js'
-    },
-    performance: { hints: false },
-    mode: prod ? "production" : "development",
-    module: {
-        rules: [
-            {
-                enforce: "pre",
-                test: /\.js$/,
-                loader: "source-map-loader",
-                exclude: [
-                    path.resolve(__dirname, 'node_modules/mobx-state-router')
-                ]
-            },
-            {
-                "oneOf": [
-                    {
-                        test: /\.(ts|tsx)$/,
-                        exclude: /node_modules/,
-                        use: 'ts-loader'
-                    },
-                    {
-                        test: /\.css$/,
-                        use: [
-                            MiniCssExtractPlugin.loader,
-                            'css-loader'
-                        ]
-                    },
-                    {
-                        test: /\.(jpg|png)$/,
-                        use: {
-                            loader: "url-loader",
-                            options: {
-                                limit: 25000,
-                            },
-                        },
-                    },
-                    {
-                        test: /.(ttf|otf|eot|svg|woff(2)?)(\?[a-z0-9]+)?$/,
-                        use: [{
-                            loader: 'file-loader',
-                            options: {
-                                name: '[name].[ext]',
-                                outputPath: 'fonts/',    // where the fonts will go
-                            }
-                        }]
-                    },
-                    {
-                        loader: require.resolve('file-loader'),
-                        exclude: [/\.(js|jsx|mjs|tsx|ts)$/, /\.html$/, /\.json$/],
-                        options: {
-                            name: 'assets/[name].[hash:8].[ext]',
-                        },
-                    }]
-            },
-
-        ]
-    },
-    devtool: "source-map",
-    resolve: {
-        modules: [path.resolve(__dirname, 'node_modules')],
-        plugins: [new TsconfigPathsPlugin({ configFile: "./tsconfig.json", logLevel: 'info' })],
-        extensions: ['.ts', '.tsx', '.js', '.json'],
-        alias: {
-            'src': path.resolve(__dirname, 'src')
-        }
-    },
-    plugins:
-        [
-        new Printer(),
-        new CleanWebpackPlugin({
-            cleanAfterEveryBuildPatterns: ['dist']
-        }),
-        new MiniCssExtractPlugin({
-            filename: "[name].[chunkhash]h" +
-            ".css",
-            chunkFilename: "[id].[chunkhash].css"
-        }),
-        new LiveReloadPlugin({appendScriptTag: !prod}),
-        new HtmlWebpackPlugin({
-            template: path.resolve(__dirname, './src/index.html'),
-            filename: 'index.html' //relative to root of the application
-        }),
-        new CompressionPlugin({
-            test: /(\?.*)?$/i
-        })
-    ]
-};
-module.exports = config;

src/Avalonia.Diagnostics/Diagnostics/VisualTreeDebug.cs

@@ -2,6 +2,7 @@ using System;
 using System.Text;
 using Avalonia.Controls;
 using Avalonia.Data;
+using Avalonia.Utilities;
 using Avalonia.VisualTree;
 
 namespace Avalonia.Diagnostics
@@ -10,9 +11,9 @@ namespace Avalonia.Diagnostics
     {
         public static string PrintVisualTree(IVisual visual)
         {
-            StringBuilder result = new StringBuilder();
+            var result = StringBuilderCache.Acquire();
             PrintVisualTree(visual, result, 0);
-            return result.ToString();
+            return StringBuilderCache.GetStringAndRelease(result);
         }
 
         private static void PrintVisualTree(IVisual visual, StringBuilder builder, int indent)

src/Avalonia.MicroCom/MicroComProxyBase.cs

@@ -65,7 +65,7 @@ namespace Avalonia.MicroCom
 
         protected virtual void Dispose(bool disposing)
         {
-            if(_nativePointer == null)
+            if(_nativePointer == IntPtr.Zero)
                 return;
             if (_ownsHandle)
             {

src/Linux/Avalonia.LinuxFramebuffer/Input/LibInput/LibInputBackend.cs

@@ -1,11 +1,9 @@
 using System;
 using System.Collections.Generic;
-using System.ComponentModel;
 using System.IO;
 using System.Threading;
 using Avalonia.Input;
 using Avalonia.Input.Raw;
-using Avalonia.Threading;
 using static Avalonia.LinuxFramebuffer.Input.LibInput.LibInputNativeUnsafeMethods; 
 namespace Avalonia.LinuxFramebuffer.Input.LibInput
 {
@@ -29,8 +27,6 @@ namespace Avalonia.LinuxFramebuffer.Input.LibInput
             new Thread(()=>InputThread(ctx)).Start();
         }
 
-        
-        
         private unsafe void InputThread(IntPtr ctx)
         {
             var fd = libinput_get_fd(ctx);
@@ -143,8 +139,6 @@ namespace Avalonia.LinuxFramebuffer.Input.LibInput
             }
             
         }
-            
-        
 
         public void Initialize(IScreenInfoProvider screen, Action<RawInputEventArgs> onInput)
         {

src/Linux/Avalonia.LinuxFramebuffer/Input/NullInput/NullInputBackend.cs

@@ -0,0 +1,16 @@
+using System;
+using Avalonia.Input;
+using Avalonia.Input.Raw;
+
+namespace Avalonia.LinuxFramebuffer.Input.NullInput;
+
+public class NullInputBackend : IInputBackend
+{
+    public void Initialize(IScreenInfoProvider screen, Action<RawInputEventArgs> onInput)
+    {
+    }
+
+    public void SetInputRoot(IInputRoot root)
+    {
+    }
+}

src/Linux/Avalonia.LinuxFramebuffer/LinuxFramebufferPlatform.cs

@@ -42,9 +42,9 @@ namespace Avalonia.LinuxFramebuffer
             Threading = new InternalPlatformThreadingInterface();
             if (_fb is IGlOutputBackend gl)
                 AvaloniaLocator.CurrentMutable.Bind<IPlatformOpenGlInterface>().ToConstant(gl.PlatformOpenGlInterface);
-            
+
             var opts = AvaloniaLocator.Current.GetService<LinuxFramebufferPlatformOptions>() ?? new LinuxFramebufferPlatformOptions();
-            
+
             AvaloniaLocator.CurrentMutable
                 .Bind<IPlatformThreadingInterface>().ToConstant(Threading)
                 .Bind<IRenderTimer>().ToConstant(new DefaultRenderTimer(opts.Fps))
@@ -59,12 +59,12 @@ namespace Avalonia.LinuxFramebuffer
                 AvaloniaLocator.Current.GetService<IPlatformOpenGlInterface>());
         }
 
-       
+
-        internal static LinuxFramebufferLifetime Initialize<T>(T builder, IOutputBackend outputBackend) where T : AppBuilderBase<T>, new()
+        internal static LinuxFramebufferLifetime Initialize<T>(T builder, IOutputBackend outputBackend, IInputBackend inputBackend) where T : AppBuilderBase<T>, new()
         {
             var platform = new LinuxFramebufferPlatform(outputBackend);
             builder.UseSkia().UseWindowingSubsystem(platform.Initialize, "fbdev");
-            return new LinuxFramebufferLifetime(platform._fb);
+            return new LinuxFramebufferLifetime(platform._fb, inputBackend);
         }
     }
 
@@ -80,13 +80,13 @@ namespace Avalonia.LinuxFramebuffer
         {
             _fb = fb;
         }
-        
+
         public LinuxFramebufferLifetime(IOutputBackend fb, IInputBackend input)
         {
             _fb = fb;
             _inputBackend = input;
         }
-        
+
         public Control MainView
         {
             get => (Control)_topLevel?.Content;
@@ -126,7 +126,7 @@ namespace Avalonia.LinuxFramebuffer
         {
             Startup?.Invoke(this, new ControlledApplicationLifetimeStartupEventArgs(args));
         }
-        
+
         public void Shutdown(int exitCode)
         {
             ExitCode = exitCode;
@@ -140,22 +140,22 @@ namespace Avalonia.LinuxFramebuffer
 
 public static class LinuxFramebufferPlatformExtensions
 {
-    public static int StartLinuxFbDev<T>(this T builder, string[] args, string fbdev = null, double scaling = 1)
+    public static int StartLinuxFbDev<T>(this T builder, string[] args, string fbdev = null, double scaling = 1, IInputBackend inputBackend = default)
         where T : AppBuilderBase<T>, new() =>
-        StartLinuxDirect(builder, args, new FbdevOutput(fileName: fbdev, format: null) { Scaling = scaling });
+        StartLinuxDirect(builder, args, new FbdevOutput(fileName: fbdev, format: null) { Scaling = scaling }, inputBackend);
-    public static int StartLinuxFbDev<T>(this T builder, string[] args, string fbdev, PixelFormat? format, double scaling)
+    public static int StartLinuxFbDev<T>(this T builder, string[] args, string fbdev, PixelFormat? format, double scaling, IInputBackend inputBackend = default)
         where T : AppBuilderBase<T>, new() =>
-        StartLinuxDirect(builder, args, new FbdevOutput(fileName: fbdev, format: format) { Scaling = scaling });
+        StartLinuxDirect(builder, args, new FbdevOutput(fileName: fbdev, format: format) { Scaling = scaling }, inputBackend);
-
+
-    public static int StartLinuxDrm<T>(this T builder, string[] args, string card = null, double scaling = 1)
+    public static int StartLinuxDrm<T>(this T builder, string[] args, string card = null, double scaling = 1, IInputBackend inputBackend = default)
-        where T : AppBuilderBase<T>, new() => StartLinuxDirect(builder, args, new DrmOutput(card) {Scaling = scaling});
+        where T : AppBuilderBase<T>, new() => StartLinuxDirect(builder, args, new DrmOutput(card) { Scaling = scaling }, inputBackend);
-    public static int StartLinuxDrm<T>(this T builder, string[] args, string card = null, bool connectorsForceProbe = false, [CanBeNull] DrmOutputOptions options = null)
+    public static int StartLinuxDrm<T>(this T builder, string[] args, string card = null, bool connectorsForceProbe = false, [CanBeNull] DrmOutputOptions options = null, IInputBackend inputBackend = default)
-        where T : AppBuilderBase<T>, new() => StartLinuxDirect(builder, args, new DrmOutput(card, connectorsForceProbe, options));
+        where T : AppBuilderBase<T>, new() => StartLinuxDirect(builder, args, new DrmOutput(card, connectorsForceProbe, options), inputBackend);
-    
+
-    public static int StartLinuxDirect<T>(this T builder, string[] args, IOutputBackend backend)
+    public static int StartLinuxDirect<T>(this T builder, string[] args, IOutputBackend outputBackend, IInputBackend inputBackend = default)
         where T : AppBuilderBase<T>, new()
     {
-        var lifetime = LinuxFramebufferPlatform.Initialize(builder, backend);
+        var lifetime = LinuxFramebufferPlatform.Initialize(builder, outputBackend, inputBackend);
         builder.SetupWithLifetime(lifetime);
         lifetime.Start(args);
         builder.Instance.Run(lifetime.Token);

src/Markup/Avalonia.Markup.Xaml.Loader/Avalonia.Markup.Xaml.Loader.csproj

@@ -7,6 +7,9 @@
     <DefineConstants>$(DefineConstants);XAMLX_INTERNAL</DefineConstants>
   </PropertyGroup>
   <Import Project="IncludeXamlIlSre.props" />
+  <ItemGroup>
+    <Compile Include="..\..\Avalonia.Base\Utilities\StringBuilderCache.cs" Link="Utilities\StringBuilderCache.cs" />
+  </ItemGroup>
   <ItemGroup>
     <PackageReference Include="System.Reflection.Emit" Version="4.3.0" />
   </ItemGroup>

src/Web/Avalonia.Web.Blazor/Avalonia.Web.Blazor.csproj

@@ -31,8 +31,6 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.AspNetCore.Components.Web" Version="6.0.8" />
-    <PackageReference Include="Microsoft.TypeScript.MSBuild" Version="4.7.4" PrivateAssets="all" />
-    <PackageReference Include="Microsoft.AspNetCore.Components.Web" Version="6.0.0" />
   </ItemGroup>
 
   <ItemGroup>

src/Web/Avalonia.Web.Blazor/Interop/AvaloniaModule.cs

@@ -4,7 +4,7 @@ namespace Avalonia.Web.Blazor.Interop
 {
     internal class AvaloniaModule : JSModuleInterop
     {
-        private AvaloniaModule(IJSRuntime js) : base(js, "./_content/Avalonia.Web.Blazor/avalonia.js")
+        private AvaloniaModule(IJSRuntime js) : base(js, "./_content/Avalonia.Web.Blazor/Avalonia.js")
         {
         }
 

src/Web/Avalonia.Web.Blazor/Interop/Storage/StorageProviderInterop.cs

@@ -12,7 +12,7 @@ namespace Avalonia.Web.Blazor.Interop.Storage
 
     internal class StorageProviderInterop : JSModuleInterop, IStorageProvider
     {
-        private const string JsFilename = "./_content/Avalonia.Web.Blazor/avaloniaStorage.js";
+        private const string JsFilename = "./_content/Avalonia.Web.Blazor/Storage.js";
         private const string PickerCancelMessage = "The user aborted a request";
 
         public static async Task<StorageProviderInterop> ImportAsync(IJSRuntime js)

src/Web/Avalonia.Web.Blazor/webapp/build.js

@@ -0,0 +1,16 @@
+require("esbuild").build({
+    entryPoints: [
+        "./modules/Avalonia.ts",
+        "./modules/Storage.ts"
+    ],
+    outdir: "../wwwroot",
+    bundle: true,
+    minify: true,
+    format: "esm",
+    target: "es2016",
+    platform: "browser",
+    sourcemap: "linked",
+    loader: {".ts": "ts"}
+  })
+  .then(() => console.log("⚡ Done"))
+  .catch(() => process.exit(1));

src/Web/Avalonia.Web.Blazor/webapp/modules/Avalonia.ts

@@ -0,0 +1,5 @@
+export { DpiWatcher } from "./Avalonia/DpiWatcher"
+export { InputHelper } from "./Avalonia/InputHelper"
+export { NativeControlHost } from "./Avalonia/NativeControlHost"
+export { SizeWatcher } from "./Avalonia/SizeWatcher"
+export { SKHtmlCanvas } from "./Avalonia/SKHtmlCanvas"

src/Web/Avalonia.Web.Blazor/webapp/modules/Avalonia/Avalonia.ts

@@ -1,5 +0,0 @@
-export { DpiWatcher } from "./DpiWatcher"
-export { InputHelper } from "./InputHelper"
-export { NativeControlHost } from "./NativeControlHost"
-export { SizeWatcher } from "./SizeWatcher"
-export { SKHtmlCanvas } from "./SKHtmlCanvas"

src/Web/Avalonia.Web.Blazor/webapp/modules/Storage.ts

@@ -0,0 +1 @@
+export { StorageProvider } from "./Storage/StorageProvider"

src/Web/Avalonia.Web.Blazor/webapp/package.json

@@ -1,16 +1,13 @@
 {
   "name": "avalonia.web",
   "scripts": {
-    "dist": "cross-env NODE_ENV=production webpack",
+    "prebuild": "tsc -noEmit",
-    "build": "cross-env NODE_ENV=development webpack"
+    "build": "node build.js"
   },
   "devDependencies": {
     "@types/emscripten": "^1.39.6",
     "@types/wicg-file-system-access": "^2020.9.5",
-    "cross-env": "^7.0.3",
-    "ts-loader": "^9.3.1",
     "typescript": "^4.7.4",
-    "webpack": "^5.73.0",
+    "esbuild": "^0.15.7"
-    "webpack-cli": "^4.10.0"
   }
 }

src/Web/Avalonia.Web.Blazor/webapp/tsconfig.json

@@ -1,14 +1,14 @@
 {
   "compilerOptions": {
-    "target": "ES6",
+    "target": "es2016",
     "strict": true,
     "sourceMap": true,
     "outDir": "../wwwroot",
-    "removeComments": true,
     "noEmitOnError": true,
+    "isolatedModules": true, // we need it for esbuild
     "lib": [
       "dom",
-      "ES6",
+      "es2016",
       "esnext.asynciterable"
     ]
   },

src/Web/Avalonia.Web.Blazor/webapp/webpack.config.js

@@ -1,40 +0,0 @@
-const path = require('path');
-const prod = process.env.NODE_ENV == 'production';
-
-module.exports = {
-    mode: prod ? "production" : "development",
-    devtool: 'source-map',
-    target: ["web", "es2020"],
-    entry: {
-        avalonia: './modules/Avalonia/Avalonia.ts',
-        avaloniaStorage: {
-            import: './modules/Storage/StorageProvider.ts',
-            dependOn: 'avalonia',
-        }
-    },
-    output: {
-        filename: '[name].js',
-        path: path.resolve(__dirname, '../wwwroot'),
-        library: {
-            type: 'module',
-        },
-    },
-    module: {
-        rules: [
-            {
-                test: /\.tsx?$/,
-                use: 'ts-loader',
-                exclude: /node_modules/,
-            },
-        ],
-    },
-    resolve: {
-        extensions: ['.ts', '.js'],
-    },
-    optimization: {
-        minimize: false
-    },
-    experiments: {
-        outputModule: true,
-    }
-};

src/Windows/Avalonia.Win32/ClipboardFormats.cs

@@ -2,9 +2,9 @@
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Linq;
-using System.Text;
 using Avalonia.Input;
 using Avalonia.Win32.Interop;
+using Avalonia.Utilities;
 
 namespace Avalonia.Win32
 {
@@ -35,9 +35,9 @@ namespace Avalonia.Win32
 
         private static string QueryFormatName(ushort format)
         {
-            StringBuilder sb = new StringBuilder(MAX_FORMAT_NAME_LENGTH);
+            var sb = StringBuilderCache.Acquire(MAX_FORMAT_NAME_LENGTH);
             if (UnmanagedMethods.GetClipboardFormatName(format, sb, sb.Capacity) > 0)
-                return sb.ToString();
+                return StringBuilderCache.GetStringAndRelease(sb);
             return null;
         }
 

src/Windows/Avalonia.Win32/Input/WindowsKeyboardDevice.cs

@@ -1,6 +1,6 @@
-using System.Text;
 using Avalonia.Controls;
 using Avalonia.Input;
+using Avalonia.Utilities;
 using Avalonia.Win32.Interop;
 
 namespace Avalonia.Win32.Input
@@ -49,7 +49,7 @@ namespace Avalonia.Win32.Input
 
         public string StringFromVirtualKey(uint virtualKey)
         {
-            StringBuilder result = new StringBuilder(256);
+            var result = StringBuilderCache.Acquire(256);
             int length = UnmanagedMethods.ToUnicode(
                 virtualKey,
                 0,
@@ -57,7 +57,7 @@ namespace Avalonia.Win32.Input
                 result,
                 256,
                 0);
-            return result.ToString();
+            return StringBuilderCache.GetStringAndRelease(result);
         }
 
         private void UpdateKeyStates()

src/Windows/Avalonia.Win32/OleDataObject.cs

@@ -6,9 +6,9 @@ using System.Linq;
 using System.Runtime.InteropServices;
 using System.Runtime.InteropServices.ComTypes;
 using System.Runtime.Serialization.Formatters.Binary;
-using System.Text;
 using Avalonia.Input;
 using Avalonia.MicroCom;
+using Avalonia.Utilities;
 using Avalonia.Win32.Interop;
 
 using IDataObject = Avalonia.Input.IDataObject;
@@ -103,11 +103,11 @@ namespace Avalonia.Win32
                 for (int i = 0; i < fileCount; i++)
                 {
                     int pathLen = UnmanagedMethods.DragQueryFile(hGlobal, i, null, 0);
-                    StringBuilder sb = new StringBuilder(pathLen+1);
+                    var sb = StringBuilderCache.Acquire(pathLen+1);
 
                     if (UnmanagedMethods.DragQueryFile(hGlobal, i, sb, sb.Capacity) == pathLen)
                     {
-                        files.Add(sb.ToString());
+                        files.Add(StringBuilderCache.GetStringAndRelease(sb));
                     }
                 }
             }

src/tools/Avalonia.Designer.HostApp/Avalonia.Designer.HostApp.csproj

@@ -16,6 +16,7 @@
   <ItemGroup>
     <Compile Include="..\..\..\src\Markup\Avalonia.Markup.Xaml.Loader\CompilerExtensions\**\*.cs" />
     <Compile Include="..\..\..\src\Markup\Avalonia.Markup.Xaml.Loader\AvaloniaXamlIlRuntimeCompiler.cs" />
+    <Compile Include="..\..\Avalonia.Base\Utilities\StringBuilderCache.cs" Link="Utilities\StringBuilderCache.cs" />
   </ItemGroup>
   <ItemGroup>
     <PackageReference Include="Avalonia.Angle.Windows.Natives" Version="2.1.0.2020091801" />

src/tools/DevGenerators/CompositionGenerator/Generator.cs

@@ -133,10 +133,6 @@ namespace Avalonia.SourceGenerator.CompositionGenerator
                 MethodDeclaration(ParseTypeName("void"), "Initialize")
                     .AddModifiers(SyntaxKind.PartialKeyword).WithSemicolonToken(Semicolon()));
 
-
-            var changesVarName = "c";
-            var changesVar = IdentifierName(changesVarName);
-
             server = server.AddMembers(
                 MethodDeclaration(ParseTypeName("void"), "DeserializeChangesExtra")
                     .AddParameterListParameters(Parameter(Identifier("c")).WithType(ParseTypeName("BatchStreamReader")))

tests/Avalonia.Base.UnitTests/Animation/SpringTests.cs

@@ -0,0 +1,118 @@
+using System;
+using Avalonia.Animation;
+using Avalonia.Animation.Easings;
+using Avalonia.Controls.Shapes;
+using Avalonia.Media;
+using Avalonia.Styling;
+using Xunit;
+
+namespace Avalonia.Base.UnitTests.Animation;
+
+public class SpringTests
+{
+    [Theory]
+    [InlineData("1,2 3,4")]
+    public void Can_Parse_Spring_Via_TypeConverter(string input)
+    {
+        var conv = new SpringTypeConverter();
+
+        var spring = (Spring)conv.ConvertFrom(input);
+
+        Assert.Equal(1, spring.Mass);
+        Assert.Equal(2, spring.Stiffness);
+        Assert.Equal(3, spring.Damping);
+        Assert.Equal(4, spring.InitialVelocity);
+    }
+
+    [Theory]
+    [InlineData("1,2F,3,4")] 
+    [InlineData("Foo,Bar,Fee,Buzz")] 
+    public void Can_Handle_Invalid_String_Via_TypeConverter(string input)
+    {
+        var conv = new SpringTypeConverter();
+
+        Assert.ThrowsAny<Exception>(() => (Spring)conv.ConvertFrom(input));
+    }
+
+    [Fact]
+    public void SplineEasing_Can_Be_Mutated()
+    {
+        var easing = new SpringEasing(1, 1, 1, 0);
+
+        Assert.Equal(0, easing.Ease(0));
+        Assert.Equal(0.34029984660829826, easing.Ease(1));
+
+        easing.Mass = 2;
+        easing.Stiffness = 2;
+        easing.Damping = 2;
+        easing.InitialVelocity = 1;
+
+        Assert.NotEqual(0.05136985716812037, easing.Ease(0.5));
+    }
+
+    [Fact]
+    public void Check_SpringEasing_Handled_properly()
+    {
+        var keyframe1 = new KeyFrame()
+        {
+            Setters =
+            {
+                new Setter(RotateTransform.AngleProperty, -2.5d),
+            },
+            KeyTime = TimeSpan.FromSeconds(0)
+        };
+
+        var keyframe2 = new KeyFrame()
+        {
+            Setters =
+            {
+                new Setter(RotateTransform.AngleProperty, 2.5d),
+            },
+            KeyTime = TimeSpan.FromSeconds(5)
+        };
+
+        var animation = new Avalonia.Animation.Animation()
+        {
+            Duration = TimeSpan.FromSeconds(5),
+            Children =
+            {
+                keyframe1,
+                keyframe2
+            },
+            IterationCount = new IterationCount(5),
+            PlaybackDirection = PlaybackDirection.Alternate,
+            Easing = new SpringEasing(1, 10, 1, 0)
+        };
+
+        var rotateTransform = new RotateTransform(-2.5);
+        var rect = new Rectangle()
+        {
+            RenderTransform = rotateTransform
+        };
+
+        var clock = new TestClock();
+        var animationRun = animation.RunAsync(rect, clock);
+
+        clock.Step(TimeSpan.Zero);
+        Assert.Equal(rotateTransform.Angle, -2.5);
+        clock.Step(TimeSpan.FromSeconds(5));
+        Assert.Equal(rotateTransform.Angle, 5.522828945000075);
+
+        var tolerance = 0.01;
+        clock.Step(TimeSpan.Parse("00:00:10.0153932"));
+        var expected = -2.499763294237805;
+        Assert.True(Math.Abs(rotateTransform.Angle - expected) <= tolerance);
+
+        clock.Step(TimeSpan.Parse("00:00:11.2655407"));
+        expected = -1.1011448950348934;
+        Assert.True(Math.Abs(rotateTransform.Angle - expected) <= tolerance);
+
+        clock.Step(TimeSpan.Parse("00:00:12.6158773"));
+        expected = 2.1264981706749007;
+        Assert.True(Math.Abs(rotateTransform.Angle - expected) <= tolerance);
+
+        clock.Step(TimeSpan.Parse("00:00:14.6495256"));
+        expected = 5.4337608446234782;
+        Assert.True(Math.Abs(rotateTransform.Angle - expected) <= tolerance);
+    }
+}

tests/Avalonia.Base.UnitTests/Input/PointerOverTests.cs

@@ -356,20 +356,28 @@ namespace Avalonia.Base.UnitTests.Input
             var impl = CreateTopLevelImplMock(renderer.Object);
 
             var invalidateRect = new Rect(0, 0, 15, 15);
+            var lastClientPosition = new Point(1, 5);
+
+            var result = new List<(object?, string, Point)>();
+            void HandleEvent(object? sender, PointerEventArgs e)
+            {
+                result.Add((sender, e.RoutedEvent!.Name, e.GetPosition(null)));
+            }
 
             Canvas canvas;
 
-            var root = CreateInputRoot(impl.Object, new Panel
+            var root = (Window)CreateInputRoot(impl.Object, new Panel
             {
                 Children =
                 {
                     (canvas = new Canvas())
                 }
             });
+            AddEnteredExitedHandlers(HandleEvent, root, canvas);
 
             // Let input know about latest device.
             SetHit(renderer, canvas);
-            impl.Object.Input!(CreateRawPointerMovedArgs(deviceMock.Object, root));
+            impl.Object.Input!(CreateRawPointerMovedArgs(deviceMock.Object, root, lastClientPosition));
             Assert.True(canvas.IsPointerOver);
 
             SetHit(renderer, canvas);
@@ -380,6 +388,52 @@ namespace Avalonia.Base.UnitTests.Input
             SetHit(renderer, null);
             renderer.Raise(r => r.SceneInvalidated += null, new SceneInvalidatedEventArgs((IRenderRoot)root, invalidateRect));
             Assert.False(canvas.IsPointerOver);
+
+            Assert.Equal(
+                new[]
+                {
+                    ((object?)canvas, nameof(InputElement.PointerEntered), lastClientPosition),
+                    (root, nameof(InputElement.PointerEntered), lastClientPosition),
+                    (canvas, nameof(InputElement.PointerExited), lastClientPosition),
+                    (root, nameof(InputElement.PointerExited), lastClientPosition),
+                },
+                result);
+        }
+
+        [Fact]
+        public void PointerOver_Invalidation_Should_Use_Previously_Captured_Element()
+        {
+            using var app = UnitTestApplication.Start(new TestServices(inputManager: new InputManager()));
+
+            var renderer = new Mock<IRenderer>();
+            var deviceMock = CreatePointerDeviceMock();
+            var impl = CreateTopLevelImplMock(renderer.Object);
+
+            var invalidateRect = new Rect(0, 0, 15, 15);
+
+            Canvas canvas1, canvas2;
+
+            var root = CreateInputRoot(impl.Object, new Panel
+            {
+                Children =
+                {
+                    (canvas1 = new Canvas()),
+                    (canvas2 = new Canvas())
+                }
+            });
+
+            canvas1.PointerMoved += (s, a) => a.Pointer.Capture(canvas1);
+
+            // Let input know about latest device.
+            SetHit(renderer, canvas1);
+            impl.Object.Input!(CreateRawPointerMovedArgs(deviceMock.Object, root));
+            Assert.True(canvas1.IsPointerOver);
+            Assert.False(canvas2.IsPointerOver);
+
+            SetHit(renderer, canvas2);
+            renderer.Raise(r => r.SceneInvalidated += null, new SceneInvalidatedEventArgs((IRenderRoot)root, invalidateRect));
+            Assert.False(canvas1.IsPointerOver);
+            Assert.True(canvas2.IsPointerOver);
         }
 
         // https://github.com/AvaloniaUI/Avalonia/issues/7748

tests/Avalonia.Base.UnitTests/Input/PointerTests.cs

@@ -8,7 +8,7 @@ using Xunit;
 
 namespace Avalonia.Base.UnitTests.Input
 {
-    public class PointerTests
+    public class PointerTests : PointerTestsBase
     {
         [Fact]
         public void On_Capture_Transfer_PointerCaptureLost_Should_Propagate_Up_To_The_Common_Parent()

tests/Avalonia.Skia.UnitTests/Media/TextFormatting/TextFormatterTests.cs

@@ -389,7 +389,7 @@ namespace Avalonia.Skia.UnitTests.Media.TextFormatting
 
                     if (textLine.Width > 300 || currentHeight + textLine.Height > 240)
                     {
-                        textLine = textLine.Collapse(new TextTrailingWordEllipsis(new ReadOnlySlice<char>(new[] { TextTrimming.s_defaultEllipsisChar }), 300, defaultProperties));
+                        textLine = textLine.Collapse(new TextTrailingWordEllipsis(new ReadOnlySlice<char>(new[] { TextTrimming.DefaultEllipsisChar }), 300, defaultProperties));
                     }
 
                     currentHeight += textLine.Height;