Don't run layout passes on hidden TopLevels.

To do this we need to pass the root to `LayoutManager`.

Fixes #4161

src/Avalonia.Controls/TopLevel.cs

@@ -315,7 +315,7 @@ namespace Avalonia.Controls
         /// <summary>
         /// Creates the layout manager for this <see cref="TopLevel" />.
         /// </summary>
-        protected virtual ILayoutManager CreateLayoutManager() => new LayoutManager();
+        protected virtual ILayoutManager CreateLayoutManager() => new LayoutManager(this);
 
         /// <summary>
         /// Handles a paint notification from <see cref="ITopLevelImpl.Resized"/>.

src/Avalonia.Layout/ILayoutManager.cs

@@ -35,6 +35,15 @@ namespace Avalonia.Layout
         /// </remarks>
         void ExecuteLayoutPass();
 
+        /// <summary>
+        /// Executes the initial layout pass on a layout root.
+        /// </summary>
+        /// <remarks>
+        /// You should not usually need to call this method explictly, the layout root will call
+        /// it to carry out the initial layout of the control.
+        /// </remarks>
+        void ExecuteInitialLayoutPass();
+
         /// <summary>
         /// Executes the initial layout pass on a layout root.
         /// </summary>
@@ -43,6 +52,7 @@ namespace Avalonia.Layout
         /// You should not usually need to call this method explictly, the layout root will call
         /// it to carry out the initial layout of the control.
         /// </remarks>
+        [Obsolete("Call ExecuteInitialLayoutPass without parameter")]
         void ExecuteInitialLayoutPass(ILayoutRoot root);
     }
 }

src/Avalonia.Layout/LayoutManager.cs

@@ -12,14 +12,16 @@ namespace Avalonia.Layout
     /// </summary>
     public class LayoutManager : ILayoutManager
     {
+        private readonly ILayoutRoot _owner;
         private readonly LayoutQueue<ILayoutable> _toMeasure = new LayoutQueue<ILayoutable>(v => !v.IsMeasureValid);
         private readonly LayoutQueue<ILayoutable> _toArrange = new LayoutQueue<ILayoutable>(v => !v.IsArrangeValid);
         private readonly Action _executeLayoutPass;
         private bool _queued;
         private bool _running;
 
-        public LayoutManager()
+        public LayoutManager(ILayoutRoot owner)
         {
+            _owner = owner ?? throw new ArgumentNullException(nameof(owner));
             _executeLayoutPass = ExecuteLayoutPass;
         }
 
@@ -73,6 +75,11 @@ namespace Avalonia.Layout
 
             Dispatcher.UIThread.VerifyAccess();
 
+            if (!_owner.IsVisible)
+            {
+                return;
+            }
+
             if (!_running)
             {
                 _running = true;
@@ -131,13 +138,13 @@ namespace Avalonia.Layout
         }
 
         /// <inheritdoc/>
-        public virtual void ExecuteInitialLayoutPass(ILayoutRoot root)
+        public virtual void ExecuteInitialLayoutPass()
         {
             try
             {
                 _running = true;
-                Measure(root);
+                Measure(_owner);
-                Arrange(root);
+                Arrange(_owner);
             }
             finally
             {
@@ -151,6 +158,17 @@ namespace Avalonia.Layout
             ExecuteLayoutPass();
         }
 
+        [Obsolete("Call ExecuteInitialLayoutPass without parameter")]
+        public void ExecuteInitialLayoutPass(ILayoutRoot root)
+        {
+            if (root != _owner)
+            {
+                throw new ArgumentException("ExecuteInitialLayoutPass called with incorrect root.");
+            }
+
+            ExecuteInitialLayoutPass();
+        }
+
         private void ExecuteMeasurePass()
         {
             while (_toMeasure.Count > 0)
@@ -228,7 +246,7 @@ namespace Avalonia.Layout
 
         private void QueueLayoutPass()
         {
-            if (!_queued && !_running)
+            if (!_queued && !_running && _owner.IsVisible)
             {
                 Dispatcher.UIThread.Post(_executeLayoutPass, DispatcherPriority.Layout);
                 _queued = true;

tests/Avalonia.Controls.UnitTests/Presenters/ItemsPresenterTests_Virtualization.cs

@@ -324,6 +324,11 @@ namespace Avalonia.Controls.UnitTests.Presenters
 
         private class TestScroller : ScrollContentPresenter, IRenderRoot, ILayoutRoot
         {
+            public TestScroller()
+            {
+                LayoutManager = new LayoutManager(this);
+            }
+
             public IRenderer Renderer { get; }
             public Size ClientSize { get; }
             public double RenderScaling => 1;
@@ -332,7 +337,7 @@ namespace Avalonia.Controls.UnitTests.Presenters
 
             public double LayoutScaling => 1;
 
-            public ILayoutManager LayoutManager { get; } = new LayoutManager();
+            public ILayoutManager LayoutManager { get; }
 
             public IRenderTarget CreateRenderTarget() => throw new NotImplementedException();
             public void Invalidate(Rect rect) => throw new NotImplementedException();

tests/Avalonia.Controls.UnitTests/Presenters/ItemsPresenterTests_Virtualization_Simple.cs

@@ -1062,6 +1062,11 @@ namespace Avalonia.Controls.UnitTests.Presenters
 
         private class TestScroller : ScrollContentPresenter, IRenderRoot, ILayoutRoot, ILogicalRoot
         {
+            public TestScroller()
+            {
+                LayoutManager = new LayoutManager(this);
+            }
+
             public IRenderer Renderer { get; }
             public Size ClientSize { get; }
             public double RenderScaling => 1;
@@ -1070,7 +1075,7 @@ namespace Avalonia.Controls.UnitTests.Presenters
 
             public double LayoutScaling => 1;
 
-            public ILayoutManager LayoutManager { get; } = new LayoutManager();
+            public ILayoutManager LayoutManager { get; }
 
             public IRenderTarget CreateRenderTarget() => throw new NotImplementedException();
             public void Invalidate(Rect rect) => throw new NotImplementedException();

tests/Avalonia.Controls.UnitTests/TopLevelTests.cs

@@ -323,7 +323,7 @@ namespace Avalonia.Controls.UnitTests
             public TestTopLevel(ITopLevelImpl impl, ILayoutManager layoutManager = null)
                 : base(impl)
             {
-                _layoutManager = layoutManager ?? new LayoutManager();
+                _layoutManager = layoutManager ?? new LayoutManager(this);
             }
 
             protected override ILayoutManager CreateLayoutManager() => _layoutManager;

tests/Avalonia.Layout.UnitTests/LayoutableTests.cs

@@ -208,14 +208,12 @@ namespace Avalonia.Layout.UnitTests
         {
             Border border1;
             Border border2;
-            var layoutManager = new LayoutManager();
             var root = new TestRoot
             {
                 Child = border1 = new Border
                 {
                     Child = border2 = new Border(),
                 },
-                LayoutManager = layoutManager,
             };
             var raised = 0;
 
@@ -233,7 +231,7 @@ namespace Avalonia.Layout.UnitTests
             root.Measure(new Size(100, 100));
             root.Arrange(new Rect(0, 0, 100, 100));
             
-            layoutManager.ExecuteLayoutPass();
+            root.LayoutManager.ExecuteLayoutPass();
 
             Assert.Equal(3, raised);
             Assert.Equal(new Rect(0, 0, 100, 100), border1.Bounds);

tests/Avalonia.UnitTests/TestRoot.cs

@@ -19,6 +19,8 @@ namespace Avalonia.UnitTests
         public TestRoot()
         {
             Renderer = Mock.Of<IRenderer>();
+            LayoutManager = new LayoutManager(this);
+            IsVisible = true;
         }
 
         public TestRoot(IControl child)
@@ -44,7 +46,7 @@ namespace Avalonia.UnitTests
 
         public double LayoutScaling { get; set; } = 1;
 
-        public ILayoutManager LayoutManager { get; set; } = new LayoutManager();
+        public ILayoutManager LayoutManager { get; set; }
 
         public double RenderScaling => 1;
 

tests/Avalonia.UnitTests/TestTemplatedRoot.cs

@@ -16,6 +16,7 @@ namespace Avalonia.UnitTests
 
         public TestTemplatedRoot()
         {
+            LayoutManager = new LayoutManager(this);
             Template = new FuncControlTemplate<TestTemplatedRoot>((x, scope) => new ContentPresenter
             {
                 Name = "PART_ContentPresenter",
@@ -28,7 +29,7 @@ namespace Avalonia.UnitTests
 
         public double LayoutScaling => 1;
 
-        public ILayoutManager LayoutManager { get; set; } = new LayoutManager();
+        public ILayoutManager LayoutManager { get; set; }
 
         public double RenderScaling => 1;