Merge pull request #8305 from AvaloniaUI/fixes/reduce-excessive-layout-passes

Fixes/reduce excessive layout passes

native/Avalonia.Native/src/OSX/WindowBaseImpl.mm

@@ -298,14 +298,15 @@ HRESULT WindowBaseImpl::Resize(double x, double y, AvnPlatformResizeReason reaso
         }
 
         @try {
-            lastSize = NSSize {x, y};
-
-            if (!_shown) {
-                BaseEvents->Resized(AvnSize{x, y}, reason);
-            }
-            else if(Window != nullptr) {
-                [Window setContentSize:lastSize];
-                [Window invalidateShadow];
+            if(x != lastSize.width || y != lastSize.height) {
+                lastSize = NSSize{x, y};
+
+                if (!_shown) {
+                    BaseEvents->Resized(AvnSize{x, y}, reason);
+                } else if (Window != nullptr) {
+                    [Window setContentSize:lastSize];
+                    [Window invalidateShadow];
+                }
             }
         }
         @finally {

src/Avalonia.Base/Layout/LayoutManager.cs

@@ -28,7 +28,7 @@ namespace Avalonia.Layout
         public LayoutManager(ILayoutRoot owner)
         {
             _owner = owner ?? throw new ArgumentNullException(nameof(owner));
-            _executeLayoutPass = ExecuteLayoutPass;
+            _executeLayoutPass = ExecuteQueuedLayoutPass;
         }
 
         public virtual event EventHandler? LayoutUpdated;
@@ -94,6 +94,16 @@ namespace Avalonia.Layout
             QueueLayoutPass();
         }
 
+        private void ExecuteQueuedLayoutPass()
+        {
+            if (!_queued)
+            {
+                return;
+            }
+            
+            ExecuteLayoutPass();
+        }
+
         /// <inheritdoc/>
         public virtual void ExecuteLayoutPass()
         {
@@ -319,8 +329,8 @@ namespace Avalonia.Layout
         {
             if (!_queued && !_running)
             {
-                Dispatcher.UIThread.Post(_executeLayoutPass, DispatcherPriority.Layout);
                 _queued = true;
+                Dispatcher.UIThread.Post(_executeLayoutPass, DispatcherPriority.Layout);
             }
         }
 

tests/Avalonia.Base.UnitTests/Layout/LayoutManagerTests.cs

@@ -2,6 +2,7 @@ using System.Collections.Generic;
 using System.Linq;
 using Avalonia.Controls;
 using Avalonia.Layout;
+using Avalonia.Threading;
 using Xunit;
 
 namespace Avalonia.Base.UnitTests.Layout
@@ -421,5 +422,22 @@ namespace Avalonia.Base.UnitTests.Layout
             Assert.Equal(new Size(200, 200), control.Bounds.Size);
             Assert.Equal(new Size(200, 200), control.DesiredSize);
         }
+        
+        [Fact]
+        public void LayoutManager_Execute_Layout_Pass_Should_Clear_Queued_LayoutPasses()
+        {
+            var control = new LayoutTestControl();
+            var root = new LayoutTestRoot { Child = control };
+
+            int layoutCount = 0;
+            root.LayoutUpdated += (_, _) => layoutCount++;
+
+            root.LayoutManager.InvalidateArrange(control);
+            root.LayoutManager.ExecuteInitialLayoutPass();
+            
+            Dispatcher.UIThread.RunJobs(DispatcherPriority.Layout);
+            
+            Assert.Equal(1, layoutCount);
+        }
     }
 }