Merge pull request #3642 from MarchingCube/optimize-affects-render

Avoid IAffectsRender subscribe attempts on values that can't implement it

src/Avalonia.Visuals/AvaloniaPropertyExtensions.cs

@@ -0,0 +1,27 @@
+using Avalonia.Media;
+
+#nullable enable
+
+namespace Avalonia
+{
+    /// <summary>
+    /// Extensions for <see cref="AvaloniaProperty"/>.
+    /// </summary>
+    public static class AvaloniaPropertyExtensions
+    {
+        /// <summary>
+        /// Checks if values of given property can affect rendering (via <see cref="IAffectsRender"/>).
+        /// </summary>
+        /// <param name="property">Property to check.</param>
+        public static bool CanValueAffectRender(this AvaloniaProperty property)
+        {
+            var propertyType = property.PropertyType;
+
+            // Only case that we are sure that property value CAN'T affect render are sealed types that don't implement
+            // the interface.
+            var cannotAffectRender = propertyType.IsSealed && !typeof(IAffectsRender).IsAssignableFrom(propertyType);
+
+            return !cannotAffectRender;
+        }
+    }
+}

src/Avalonia.Visuals/Media/Brush.cs

@@ -69,14 +69,14 @@ namespace Avalonia.Media
         protected static void AffectsRender<T>(params AvaloniaProperty[] properties)
             where T : Brush
         {
-            void Invalidate(AvaloniaPropertyChangedEventArgs e)
+            static void Invalidate(AvaloniaPropertyChangedEventArgs e)
             {
                 (e.Sender as T)?.RaiseInvalidated(EventArgs.Empty);
             }
 
             foreach (var property in properties)
             {
-                property.Changed.Subscribe(Invalidate);
+                property.Changed.Subscribe(e => Invalidate(e));
             }
         }
 

src/Avalonia.Visuals/Media/Pen.cs

@@ -2,7 +2,6 @@
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
 using System;
-using System.Collections.Generic;
 using Avalonia.Media.Immutable;
 using Avalonia.Utilities;
 
@@ -197,7 +196,15 @@ namespace Avalonia.Media
         protected static void AffectsRender<T>(params AvaloniaProperty[] properties)
             where T : Pen
         {
-            void Invalidate(AvaloniaPropertyChangedEventArgs e)
+            static void Invalidate(AvaloniaPropertyChangedEventArgs e)
+            {
+                if (e.Sender is T sender)
+                {
+                    sender.RaiseInvalidated(EventArgs.Empty);
+                }
+            }
+
+            static void InvalidateAndSubscribe(AvaloniaPropertyChangedEventArgs e)
             {
                 if (e.Sender is T sender)
                 {
@@ -223,7 +230,14 @@ namespace Avalonia.Media
 
             foreach (var property in properties)
             {
-                property.Changed.Subscribe(Invalidate);
+                if (property.CanValueAffectRender())
+                {
+                    property.Changed.Subscribe(e => InvalidateAndSubscribe(e));
+                }
+                else
+                {
+                    property.Changed.Subscribe(e => Invalidate(e));
+                }
             }
         }
 

src/Avalonia.Visuals/Visual.cs

@@ -3,7 +3,6 @@
 
 using System;
 using System.Collections.Specialized;
-using System.Linq;
 using Avalonia.Collections;
 using Avalonia.Data;
 using Avalonia.Logging;
@@ -336,7 +335,15 @@ namespace Avalonia
         protected static void AffectsRender<T>(params AvaloniaProperty[] properties)
             where T : Visual
         {
-            void Invalidate(AvaloniaPropertyChangedEventArgs e)
+            static void Invalidate(AvaloniaPropertyChangedEventArgs e)
+            {
+                if (e.Sender is T sender)
+                {
+                    sender.InvalidateVisual();
+                }
+            }
+
+            static void InvalidateAndSubscribe(AvaloniaPropertyChangedEventArgs e)
             {
                 if (e.Sender is T sender)
                 {
@@ -347,7 +354,7 @@ namespace Avalonia
 
                     if (e.NewValue is IAffectsRender newValue)
                     {
-                        WeakEventHandlerManager.Subscribe<IAffectsRender, EventArgs, T>(newValue, nameof(newValue.Invalidated), sender.AffectsRenderInvalidated);                        
+                        WeakEventHandlerManager.Subscribe<IAffectsRender, EventArgs, T>(newValue, nameof(newValue.Invalidated), sender.AffectsRenderInvalidated);
                     }
 
                     sender.InvalidateVisual();
@@ -356,7 +363,14 @@ namespace Avalonia
 
             foreach (var property in properties)
             {
-                property.Changed.Subscribe(Invalidate);
+                if (property.CanValueAffectRender())
+                {
+                    property.Changed.Subscribe(e => InvalidateAndSubscribe(e));
+                }
+                else
+                {
+                    property.Changed.Subscribe(e => Invalidate(e));
+                }
             }
         }