Bring back iOS SetNeedsLayout propagation via inheritance

albyrock87 · albyrock87 · commit ec246acb9e9b · 2025-03-16T14:40:37.000+01:00
diff --git a/src/Controls/src/Core/Compatibility/Handlers/iOS/VisualElementRenderer.cs b/src/Controls/src/Core/Compatibility/Handlers/iOS/VisualElementRenderer.cs
@@ -99,7 +99,15 @@ void IPlatformMeasureInvalidationController.InvalidateAncestorsMeasuresWhenMoved
 			_invalidateParentWhenMovedToWindow = true;
 		}
 
-		void IPlatformMeasureInvalidationController.InvalidateMeasure(bool isPropagating) => SetNeedsLayout();
+		public override void SetNeedsLayout()
+		{
+			base.SetNeedsLayout();
+
+			if (IPlatformMeasureInvalidationController.IsInvalidating)
+			{
+				this.InvalidateParentMeasure();
+			}
+		}
 
 		public override void MovedToWindow()
 		{
diff --git a/src/Controls/src/Core/Handlers/Items/iOS/ItemsViewCell.cs b/src/Controls/src/Core/Handlers/Items/iOS/ItemsViewCell.cs
@@ -14,6 +14,7 @@ public abstract class ItemsViewCell : UICollectionViewCell
 		protected ItemsViewCell(CGRect frame) : base(frame)
 		{
 			ContentView.BackgroundColor = UIColor.Clear;
+			ContentView.Tag = IPlatformMeasureInvalidationController.PropagationProxyTag;
 
 			var selectedBackgroundView = new UIView
 			{
diff --git a/src/Controls/src/Core/Handlers/Items/iOS/MauiCollectionView.cs b/src/Controls/src/Core/Handlers/Items/iOS/MauiCollectionView.cs
@@ -25,11 +25,13 @@ void IPlatformMeasureInvalidationController.InvalidateAncestorsMeasuresWhenMoved
 		_invalidateParentWhenMovedToWindow = true;
 	}
 
-	void IPlatformMeasureInvalidationController.InvalidateMeasure(bool isPropagating)
+	public override void SetNeedsLayout()
 	{
-		if (!isPropagating)
+		base.SetNeedsLayout();
+
+		if (IPlatformMeasureInvalidationController.IsInvalidatingSelf)
 		{
-			SetNeedsLayout();
+			this.InvalidateParentMeasure();
 		}
 	}
 
diff --git a/src/Controls/src/Core/Handlers/Items2/iOS/ItemsViewCell2.cs b/src/Controls/src/Core/Handlers/Items2/iOS/ItemsViewCell2.cs
@@ -14,6 +14,7 @@ public abstract class ItemsViewCell2 : UICollectionViewCell
 		protected ItemsViewCell2(CGRect frame) : base(frame)
 		{
 			ContentView.BackgroundColor = UIColor.Clear;
+			ContentView.Tag = IPlatformMeasureInvalidationController.PropagationProxyTag;
 
 			var selectedBackgroundView = new UIView
 			{
diff --git a/src/Controls/src/Core/PublicAPI/net-ios/PublicAPI.Unshipped.txt b/src/Controls/src/Core/PublicAPI/net-ios/PublicAPI.Unshipped.txt
@@ -1,5 +1,6 @@
 #nullable enable
 Microsoft.Maui.Controls.StyleableElement.Style.get -> Microsoft.Maui.Controls.Style?
+override Microsoft.Maui.Controls.Handlers.Compatibility.VisualElementRenderer<TElement>.SetNeedsLayout() -> void
 override Microsoft.Maui.Controls.Handlers.Items2.ItemsViewHandler2<TItemsView>.GetDesiredSize(double widthConstraint, double heightConstraint) -> Microsoft.Maui.Graphics.Size
 ~abstract Microsoft.Maui.Controls.Handlers.Items2.ItemsViewHandler2<TItemsView>.CreateController(TItemsView newElement, UIKit.UICollectionViewLayout layout) -> Microsoft.Maui.Controls.Handlers.Items2.ItemsViewController2<TItemsView>
 ~abstract Microsoft.Maui.Controls.Handlers.Items2.ItemsViewHandler2<TItemsView>.SelectLayout() -> UIKit.UICollectionViewLayout
diff --git a/src/Controls/src/Core/PublicAPI/net-maccatalyst/PublicAPI.Unshipped.txt b/src/Controls/src/Core/PublicAPI/net-maccatalyst/PublicAPI.Unshipped.txt
@@ -1,5 +1,6 @@
 #nullable enable
 Microsoft.Maui.Controls.StyleableElement.Style.get -> Microsoft.Maui.Controls.Style?
+override Microsoft.Maui.Controls.Handlers.Compatibility.VisualElementRenderer<TElement>.SetNeedsLayout() -> void
 override Microsoft.Maui.Controls.Handlers.Items2.ItemsViewHandler2<TItemsView>.GetDesiredSize(double widthConstraint, double heightConstraint) -> Microsoft.Maui.Graphics.Size
 ~abstract Microsoft.Maui.Controls.Handlers.Items2.ItemsViewHandler2<TItemsView>.CreateController(TItemsView newElement, UIKit.UICollectionViewLayout layout) -> Microsoft.Maui.Controls.Handlers.Items2.ItemsViewController2<TItemsView>
 ~abstract Microsoft.Maui.Controls.Handlers.Items2.ItemsViewHandler2<TItemsView>.SelectLayout() -> UIKit.UICollectionViewLayout
diff --git a/src/Core/src/Handlers/Page/PageHandler.iOS.cs b/src/Core/src/Handlers/Page/PageHandler.iOS.cs
@@ -25,8 +25,8 @@ public override void SetVirtualView(IView view)
 		{
 			base.SetVirtualView(view);
 
-			// Ensure we tag the ContentView as a Page so that InvalidateAncestorsMeasures can stop propagation here
-			PlatformView.IsPage = true;
+			// Ensure we mark this as root view so the invalidation propagation stops here
+			PlatformView.IsRootView = true;
 		}
 
 		public static void MapBackground(IPageHandler handler, IContentView page)
diff --git a/src/Core/src/Platform/iOS/ContentView.cs b/src/Core/src/Platform/iOS/ContentView.cs
@@ -16,8 +16,6 @@ public class ContentView : MauiView
 		// verify we're using the correct subview for masking (and any other purposes)
 		internal const nint ContentTag = 0x63D2A0;
 
-		internal bool IsPage { get; set; }
-
 		public ContentView()
 		{
 			if (OperatingSystem.IsIOSVersionAtLeast(13) || OperatingSystem.IsMacCatalystVersionAtLeast(13, 1))
diff --git a/src/Core/src/Platform/iOS/IPlatformMeasureInvalidationController.cs b/src/Core/src/Platform/iOS/IPlatformMeasureInvalidationController.cs
@@ -1,7 +1,41 @@
+using UIKit;
+
 namespace Microsoft.Maui.Platform;
 
 internal interface IPlatformMeasureInvalidationController
 {
+	/// <summary>
+	/// Marks a UIView with this tag when it's not possible to use inheritance to override SetNeedsLayout.
+	/// When this tag is found, the invalidation is automatically propagated to the parent.
+	/// </summary>
+	const nint PropagationProxyTag = 0x845fff;
+
+	static int _invalidationDepth;
+
+	/// <summary>
+	/// Gets whether we're currently running an invalidation pass.
+	/// </summary>
+	public static bool IsInvalidating => _invalidationDepth > 0;
+
+	/// <summary>
+	/// Gets whether the current invalidation pass is invalidating the view which triggered the invalidation.
+	/// </summary>
+	public static bool IsInvalidatingSelf => _invalidationDepth == 1;
+
+	/// <summary>
+	/// Gets whether the current invalidation pass is invalidating the ancestors of the view which triggered the invalidation.
+	/// </summary>
+	public static bool IsPropagatingInvalidation => _invalidationDepth > 1;
+
+	public static void BeginInvalidation() => _invalidationDepth = 0;
+	public static void BeginAncestorsInvalidation() => _invalidationDepth = 1;
+	public static void EndInvalidation() => _invalidationDepth = 0;
+
+	public static void SetNeedsLayout(UIView view)
+	{
+		++_invalidationDepth;
+		view.SetNeedsLayout();
+	}
+
 	void InvalidateAncestorsMeasuresWhenMovedToWindow();
-	void InvalidateMeasure(bool isPropagating = false);
 }
diff --git a/src/Core/src/Platform/iOS/MauiScrollView.cs b/src/Core/src/Platform/iOS/MauiScrollView.cs
@@ -87,10 +87,19 @@ void IPlatformMeasureInvalidationController.InvalidateAncestorsMeasuresWhenMoved
 			_invalidateParentWhenMovedToWindow = true;
 		}
 
-		void IPlatformMeasureInvalidationController.InvalidateMeasure(bool isPropagating)
+		public override void SetNeedsLayout()
 		{
-			SetNeedsLayout();
-			InvalidateConstraintsCache();
+			base.SetNeedsLayout();
+
+			if (IPlatformMeasureInvalidationController.IsInvalidating)
+			{
+				InvalidateConstraintsCache();
+			}
+
+			if (IPlatformMeasureInvalidationController.IsInvalidatingSelf)
+			{
+				this.InvalidateParentMeasure();
+			}
 		}
 
 		bool IsMeasureValid(double widthConstraint, double heightConstraint)
diff --git a/src/Core/src/Platform/iOS/MauiView.cs b/src/Core/src/Platform/iOS/MauiView.cs
@@ -18,6 +18,8 @@ public abstract class MauiView : UIView, ICrossPlatformLayoutBacking, IVisualTre
 		WeakReference<IView>? _reference;
 		WeakReference<ICrossPlatformLayout>? _crossPlatformLayoutReference;
 
+		internal bool IsRootView { get; set; }
+
 		public IView? View
 		{
 			get => _reference != null && _reference.TryGetTarget(out var v) ? v : null;
@@ -163,10 +165,19 @@ void IPlatformMeasureInvalidationController.InvalidateAncestorsMeasuresWhenMoved
 			_invalidateParentWhenMovedToWindow = true;
 		}
 
-		void IPlatformMeasureInvalidationController.InvalidateMeasure(bool isPropagating)
+		public override void SetNeedsLayout()
 		{
-			InvalidateConstraintsCache();
-			SetNeedsLayout();
+			base.SetNeedsLayout();
+
+			if (IPlatformMeasureInvalidationController.IsInvalidating)
+			{
+				InvalidateConstraintsCache();
+
+				if (!IsRootView)
+				{
+					this.InvalidateParentMeasure();
+				}
+			}
 		}
 
 		[UnconditionalSuppressMessage("Memory", "MEM0002", Justification = IUIViewLifeCycleEvents.UnconditionalSuppressMessage)]
diff --git a/src/Core/src/Platform/iOS/ViewExtensions.cs b/src/Core/src/Platform/iOS/ViewExtensions.cs
@@ -282,62 +282,59 @@ static void UpdateBackgroundLayers(this CALayer[] layers, string layerName, CGRe
 		/// </remarks>
 		public static void InvalidateMeasure(this UIView platformView, IView view)
 		{
-			if (platformView is IPlatformMeasureInvalidationController mauiPlatformView)
-			{
-				mauiPlatformView.InvalidateMeasure();
-			}
-			else
+			// Since SetNeedsLayout can only be called on the main thread, there’s no risk of concurrent execution.
+			// We can safely use a static context to determine whether we're invalidating measures or not.
+			// This ensures that `SetNeedsLayout` propagation occurs only when invalidation is triggered by MAUI.
+			// We avoid propagation when `SetNeedsLayout` is triggered by iOS, such as during transformations
+			// (e.g., Translate, Scale, Rotate) that move the layer partially offscreen (see https://github.com/dotnet/maui/issues/24996).
+			// Unnecessary invalidations during animations can cause significant performance slowdowns.
+			IPlatformMeasureInvalidationController.BeginInvalidation();
+			IPlatformMeasureInvalidationController.SetNeedsLayout(platformView);
+
+			// If platformView is not implementing measure invalidation propagation, we need to manually invalidate the parent view
+			if (platformView is not IPlatformMeasureInvalidationController && platformView.Superview is { } superview)
 			{
-				platformView.SetNeedsLayout();
+				IPlatformMeasureInvalidationController.SetNeedsLayout(superview);
 			}
 
-			platformView.InvalidateAncestorsMeasures();
+			IPlatformMeasureInvalidationController.EndInvalidation();
 		}
 
-		internal static void InvalidateAncestorsMeasures(this UIView child)
+		internal static void InvalidateAncestorsMeasures(this UIView platformView)
 		{
-			var childMauiPlatformLayout = child as IPlatformMeasureInvalidationController;
+			IPlatformMeasureInvalidationController.BeginAncestorsInvalidation();
+			InvalidateParentMeasure(platformView);
+			IPlatformMeasureInvalidationController.EndInvalidation();
+		}
 
-			while (true)
+		internal static void InvalidateParentMeasure(this UIView child)
+		{
+			// We verify the presence of a Window to prevent scenarios where an invalidate might propagate up the view hierarchy  
+			// to a SuperView that has already been disposed. Accessing such a disposed view would result in a crash (see #24032).  
+			// This validation is only possible using `IMauiPlatformView`, as it provides a way to schedule an invalidation when the view is moved to window.  
+			// For other cases, we accept the risk since avoiding it could lead to the layout not being updated properly.
+			if (child.Window is null && child is IPlatformMeasureInvalidationController childMauiPlatformLayout)
 			{
-				// We verify the presence of a Window to prevent scenarios where an invalidate might propagate up the view hierarchy  
-				// to a SuperView that has already been disposed. Accessing such a disposed view would result in a crash (see #24032).  
-				// This validation is only possible using `IMauiPlatformView`, as it provides a way to schedule an invalidation when the view is moved to window.  
-				// For other cases, we accept the risk since avoiding it could lead to the layout not being updated properly.
-				if (childMauiPlatformLayout is not null && child.Window is null)
-				{
-					childMauiPlatformLayout.InvalidateAncestorsMeasuresWhenMovedToWindow();
-					return;
-				}
+				childMauiPlatformLayout.InvalidateAncestorsMeasuresWhenMovedToWindow();
+				return;
+			}
 
-				var superview = child.Superview;
-				if (superview is null)
-				{
-					return;
-				}
+			var superview = child.Superview;
+			if (superview is null)
+			{
+				return;
+			}
 
-				// Now invalidate the parent view
-				var superviewMauiPlatformLayout = superview as IPlatformMeasureInvalidationController;
-				if (superviewMauiPlatformLayout is not null)
-				{
-					superviewMauiPlatformLayout.InvalidateMeasure(isPropagating: true);
-				}
-				else
-				{
-					superview.SetNeedsLayout();
-				}
+			IPlatformMeasureInvalidationController.SetNeedsLayout(superview);
 
-				// Potential improvement: if the MAUI view (superview here) is constrained to a fixed size, we could stop propagating
-				// when doing this, we must pay attention to a scenario where a non-fixed-size view becomes fixed-size
-				if (superview is ContentView { IsPage: true } or UIScrollView)
+			while (superview?.Tag == IPlatformMeasureInvalidationController.PropagationProxyTag)
+			{
+				superview = superview.Superview;
+
+				if (superview is not null)
 				{
-					// We reached the root view or a scrollable area (includes collection view), stop propagating
-					// The view will eventually watch its content size and invoke InvalidateAncestorsMeasures when needed
-					return;
+					IPlatformMeasureInvalidationController.SetNeedsLayout(superview);
 				}
-
-				child = superview;
-				childMauiPlatformLayout = superviewMauiPlatformLayout;
 			}
 		}
 
diff --git a/src/Core/src/Platform/iOS/WrapperView.cs b/src/Core/src/Platform/iOS/WrapperView.cs
@@ -319,10 +319,15 @@ void IPlatformMeasureInvalidationController.InvalidateAncestorsMeasuresWhenMoved
 			_invalidateParentWhenMovedToWindow = true;
 		}
 
-		void IPlatformMeasureInvalidationController.InvalidateMeasure(bool isPropagating)
+		public override void SetNeedsLayout()
 		{
-			InvalidateConstraintsCache();
-			SetNeedsLayout();
+			base.SetNeedsLayout();
+
+			if (IPlatformMeasureInvalidationController.IsInvalidating)
+			{
+				InvalidateConstraintsCache();
+				this.InvalidateParentMeasure();
+			}
 		}
 
 		[UnconditionalSuppressMessage("Memory", "MEM0002", Justification = IUIViewLifeCycleEvents.UnconditionalSuppressMessage)]
diff --git a/src/Core/src/PublicAPI/net-ios/PublicAPI.Unshipped.txt b/src/Core/src/PublicAPI/net-ios/PublicAPI.Unshipped.txt
@@ -54,6 +54,7 @@ override Microsoft.Maui.Handlers.HybridWebViewHandler.ConnectHandler(WebKit.WKWe
 override Microsoft.Maui.Handlers.HybridWebViewHandler.CreatePlatformView() -> WebKit.WKWebView!
 override Microsoft.Maui.Handlers.HybridWebViewHandler.DisconnectHandler(WebKit.WKWebView! platformView) -> void
 override Microsoft.Maui.Platform.MauiScrollView.LayoutSubviews() -> void
+override Microsoft.Maui.Platform.MauiScrollView.SetNeedsLayout() -> void
 override Microsoft.Maui.Platform.MauiScrollView.SizeThatFits(CoreGraphics.CGSize size) -> CoreGraphics.CGSize
 *REMOVED*override Microsoft.Maui.Handlers.ScrollViewHandler.GetDesiredSize(double widthConstraint, double heightConstraint) -> Microsoft.Maui.Graphics.Size
 *REMOVED*override Microsoft.Maui.Handlers.ScrollViewHandler.PlatformArrange(Microsoft.Maui.Graphics.Rect rect) -> void
@@ -88,5 +89,3 @@ override Microsoft.Maui.Handlers.WindowHandler.DisconnectHandler(UIKit.UIWindow!
 *REMOVED*override Microsoft.Maui.Handlers.ScrollViewHandler.NeedsContainer.get -> bool
 override Microsoft.Maui.Handlers.ImageButtonHandler.SetupContainer() -> void
 override Microsoft.Maui.Handlers.PageHandler.SetVirtualView(Microsoft.Maui.IView! view) -> void
-*REMOVED*override Microsoft.Maui.Platform.WrapperView.SetNeedsLayout() -> void
-*REMOVED*override Microsoft.Maui.Platform.MauiView.SetNeedsLayout() -> void
diff --git a/src/Core/src/PublicAPI/net-maccatalyst/PublicAPI.Unshipped.txt b/src/Core/src/PublicAPI/net-maccatalyst/PublicAPI.Unshipped.txt
@@ -55,6 +55,7 @@ override Microsoft.Maui.Handlers.HybridWebViewHandler.ConnectHandler(WebKit.WKWe
 override Microsoft.Maui.Handlers.HybridWebViewHandler.CreatePlatformView() -> WebKit.WKWebView!
 override Microsoft.Maui.Handlers.HybridWebViewHandler.DisconnectHandler(WebKit.WKWebView! platformView) -> void
 override Microsoft.Maui.Platform.MauiScrollView.LayoutSubviews() -> void
+override Microsoft.Maui.Platform.MauiScrollView.SetNeedsLayout() -> void
 override Microsoft.Maui.Platform.MauiScrollView.SizeThatFits(CoreGraphics.CGSize size) -> CoreGraphics.CGSize
 *REMOVED*override Microsoft.Maui.Handlers.ScrollViewHandler.GetDesiredSize(double widthConstraint, double heightConstraint) -> Microsoft.Maui.Graphics.Size
 *REMOVED*override Microsoft.Maui.Handlers.ScrollViewHandler.PlatformArrange(Microsoft.Maui.Graphics.Rect rect) -> void
@@ -89,5 +90,4 @@ override Microsoft.Maui.Handlers.WindowHandler.DisconnectHandler(UIKit.UIWindow!
 *REMOVED*override Microsoft.Maui.Handlers.ScrollViewHandler.NeedsContainer.get -> bool
 override Microsoft.Maui.Handlers.ImageButtonHandler.SetupContainer() -> void
 override Microsoft.Maui.Handlers.PageHandler.SetVirtualView(Microsoft.Maui.IView! view) -> void
-*REMOVED*override Microsoft.Maui.Platform.WrapperView.SetNeedsLayout() -> void
-*REMOVED*override Microsoft.Maui.Platform.MauiView.SetNeedsLayout() -> void
+

Original file line number	Diff line number	Diff line change
`@@ -14,6 +14,7 @@ public abstract class ItemsViewCell : UICollectionViewCell`
`14`	`14`	`protected ItemsViewCell(CGRect frame) : base(frame)`
`15`	`15`	`{`
`16`	`16`	`ContentView.BackgroundColor = UIColor.Clear;`
	`17`	`+ ContentView.Tag = IPlatformMeasureInvalidationController.PropagationProxyTag;`
`17`	`18`
`18`	`19`	`var selectedBackgroundView = new UIView`
`19`	`20`	`{`
Original file line number	Diff line number	Diff line change
`@@ -25,11 +25,13 @@ void IPlatformMeasureInvalidationController.InvalidateAncestorsMeasuresWhenMoved`
`25`	`25`	`_invalidateParentWhenMovedToWindow = true;`
`26`	`26`	`}`
`27`	`27`
`28`		`- void IPlatformMeasureInvalidationController.InvalidateMeasure(bool isPropagating)`
	`28`	`+ public override void SetNeedsLayout()`
`29`	`29`	`{`
`30`		`- if (!isPropagating)`
	`30`	`+ base.SetNeedsLayout();`
	`31`	`+`
	`32`	`+ if (IPlatformMeasureInvalidationController.IsInvalidatingSelf)`
`31`	`33`	`{`
`32`		`- SetNeedsLayout();`
	`34`	`+ this.InvalidateParentMeasure();`
`33`	`35`	`}`
`34`	`36`	`}`
`35`	`37`
Original file line number	Diff line number	Diff line change
`@@ -25,8 +25,8 @@ public override void SetVirtualView(IView view)`
`25`	`25`	`{`
`26`	`26`	`base.SetVirtualView(view);`
`27`	`27`
`28`		`- // Ensure we tag the ContentView as a Page so that InvalidateAncestorsMeasures can stop propagation here`
`29`		`- PlatformView.IsPage = true;`
	`28`	`+ // Ensure we mark this as root view so the invalidation propagation stops here`
	`29`	`+ PlatformView.IsRootView = true;`
`30`	`30`	`}`
`31`	`31`
`32`	`32`	`public static void MapBackground(IPageHandler handler, IContentView page)`
Original file line number	Diff line number	Diff line change
`@@ -16,8 +16,6 @@ public class ContentView : MauiView`
`16`	`16`	`// verify we're using the correct subview for masking (and any other purposes)`
`17`	`17`	`internal const nint ContentTag = 0x63D2A0;`
`18`	`18`
`19`		`- internal bool IsPage { get; set; }`
`20`		`-`
`21`	`19`	`public ContentView()`
`22`	`20`	`{`
`23`	`21`	`if (OperatingSystem.IsIOSVersionAtLeast(13) \|\| OperatingSystem.IsMacCatalystVersionAtLeast(13, 1))`