Merge pull request #18707 from unoplatform/dev/xygu/20241104/ios-nega…

…tive-margin-clipping

fix(ios): negative margin clipped on device rotate

src/Uno.UI.RuntimeTests/Tests/Windows_UI_Xaml_Controls/Given_ListViewBase.Measure.cs

@@ -1,15 +1,18 @@
 using System;
 using System.Collections.Generic;
+using System.Collections.ObjectModel;
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using Microsoft.UI.Xaml;
 using Microsoft.UI.Xaml.Controls;
 using Microsoft.UI.Xaml.Controls.Primitives;
-using Uno.UI.RuntimeTests.Extensions;
-using System.Collections.ObjectModel;
 using Windows.Foundation;
+using Uno.UI.Helpers;
+using Uno.UI.RuntimeTests.Extensions;
+using Uno.UI.RuntimeTests.Helpers;
+
 #if WINAPPSDK
 using Uno.UI.Extensions;
 #elif __IOS__
@@ -442,6 +445,44 @@ public async Task When_ItemsSource_INCC_StartTwo_RemoveOne()
 			await WindowHelper.WaitFor(() => Math.Abs(SUT.ActualHeight - 29) <= Epsilon, message: $"ListView failed to shrink from removing item: (ActualHeight: {SUT.ActualHeight})");
 		}
 
+#if __IOS__ || __ANDROID__
+		[TestMethod]
+		[RunsOnUIThread]
+		public async Task When_Item_With_NegativeMargin_AsdAsd() // todo@xy: remove asdasd
+		{
+			const string PathData = "M 2 2 H 18 V 18 H 2 Z M 3 3 V 17 H 17 V 3 Z"; // 18x18 square with 1px border located at 2,2
+			var setup = new ListView
+			{
+				ItemsSource = Enumerable.Range(0, 1).ToArray(),
+				ItemTemplate = XamlHelper.LoadXaml<DataTemplate>($$"""
+					<DataTemplate>
+						<Grid Background="SkyBlue">
+							<Border x:Name="SutBorder" Background="Pink">
+								<PathIcon x:Name="SUT"
+									Data="{{PathData}}" Foreground="Red"
+									Width="20" Height="20"
+									Margin="0,-10,0,0"
+									HorizontalAlignment="Center" VerticalAlignment="Center" />
+							</Border>
+						</Grid>
+					</DataTemplate>
+				"""),
+			};
+
+			await UITestHelper.Load(setup);
+
+			// We can't really test rotating the device in the context of runtime tests. But still, this is a good repro.
+			// When loaded, we should see a red square, whose lower half is sitting in a pink background.
+			// When you rotate the device (portrait <-> landscape), the red square should still be fully visible.
+
+			// Previously, there is a bug where rotating could cause the view with negative padding to be clipped.
+			// The visual hierarchy needs a special setup, it is just the easiest to replicate with a ListView...
+
+			// It can be verified by checking `.Layer.Mask` remains consistent for the visual tree under ListView,
+			// before and after the device rotation. In this case, it was the SutBorder that magically had a `.Layer.Mask` assigned.
+		}
+#endif
+
 		// Works around ScrollIntoView() not implemented for all platforms
 		private static void ScrollTo(ListViewBase listViewBase, double vOffset)
 		{

src/Uno.UI/UI/Xaml/Controls/Border/BorderLayerRenderer.iOSmacOS.cs

@@ -427,13 +427,19 @@ GradientBrush gradientBorder when gradientBorder.CanApplyToBorder(cornerRadius)
 			sublayers.Add(backgroundLayer);
 			parent.InsertSublayer(backgroundLayer, insertionIndex);
 
-			parent.Mask = new CAShapeLayer()
+			// Normally, the parent.Mask (or owner.Layer.Mask) is usually cleared by ApplyNativeClip that follows.
+			// However, on device rotation (portrait <-> landscape), ApplyNativeClip happens before this method, causing the view to have an unwanted clipping.
+			// Here, we are reusing the logics of ApplyNativeClip to decide when to not apply the mask (as it would be cleared anyways).
+			if (owner.GetNativeClippedViewport().IsFinite)
 			{
-				Path = outerPath,
-				Frame = area,
-				// We only use the fill color to create the mask area
-				FillColor = _Color.White.CGColor,
-			};
+				parent.Mask = new CAShapeLayer()
+				{
+					Path = outerPath,
+					Frame = area,
+					// We only use the fill color to create the mask area
+					FillColor = _Color.White.CGColor,
+				};
+			}
 
 			updatedBoundsPath = outerPath;
 		}

src/Uno.UI/UI/Xaml/UIElement.cs

@@ -931,6 +931,16 @@ internal void ApplyClip()
 #elif __WASM__
 			InvalidateArrange();
 #else
+			var rect = GetNativeClippedViewport();
+
+			ApplyNativeClip(rect);
+			OnViewportUpdated(rect);
+#endif
+		}
+
+#if !(__SKIA__ || __WASM__)
+		internal Rect GetNativeClippedViewport()
+		{
 			Rect rect;
 
 			if (Clip == null)
@@ -957,10 +967,9 @@ internal void ApplyClip()
 				}
 			}
 
-			ApplyNativeClip(rect);
-			OnViewportUpdated(rect);
-#endif
+			return rect;
 		}
+#endif
 
 		partial void ApplyNativeClip(Rect rect
 #if __SKIA__

src/Uno.UI/UI/Xaml/UIElement.iOS.cs

@@ -63,12 +63,7 @@ internal bool IsArrangeDirtyPath
 
 		partial void ApplyNativeClip(Rect rect)
 		{
-			if (rect.IsEmpty
-				|| double.IsPositiveInfinity(rect.X)
-				|| double.IsPositiveInfinity(rect.Y)
-				|| double.IsPositiveInfinity(rect.Width)
-				|| double.IsPositiveInfinity(rect.Height)
-			)
+			if (!rect.IsFinite)
 			{
 				if (!ClippingIsSetByCornerRadius)
 				{