Merge pull request #19004 from unoplatform/dev/mazi/translate-load

src/Uno.UI.RuntimeTests/Tests/Windows_UI_Xaml/Given_UIElement.cs

@@ -1566,6 +1566,32 @@ public async Task When_Element_Has_Translation_And_Visual_Has_Offset()
 		}
 #endif
 
+		[TestMethod]
+		[RunsOnUIThread]
+#if !__SKIA__
+		[Ignore("Translation X and Y axis is currently supported on Skia only")]
+#endif
+		public async Task When_Translation_On_Load()
+		{
+			var sut = new Rectangle()
+			{
+				Width = 100,
+				Height = 100,
+				Fill = new SolidColorBrush(Microsoft.UI.Colors.Blue),
+			};
+			var canvas = new Canvas();
+			canvas.Width = 200;
+			canvas.Height = 200;
+			canvas.Children.Add(sut);
+			TestServices.WindowHelper.WindowContent = canvas;
+			await TestServices.WindowHelper.WaitForLoaded(sut);
+			sut.Translation += new Vector3(100, 100, 128);
+			await TestServices.WindowHelper.WaitForIdle();
+			var bitmap = await UITestHelper.ScreenShot(canvas);
+			ImageAssert.DoesNotHaveColorAt(bitmap, new Windows.Foundation.Point(50, 50), Microsoft.UI.Colors.Blue);
+			ImageAssert.HasColorAt(bitmap, new Windows.Foundation.Point(150, 150), Microsoft.UI.Colors.Blue);
+		}
+
 #if HAS_UNO
 		[TestMethod]
 		[RunsOnUIThread]

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

@@ -47,6 +47,9 @@ namespace Microsoft.UI.Xaml
 	public partial class UIElement : DependencyObject, IXUidProvider
 	{
 		private protected static bool _traceLayoutCycle;
+#if !__SKIA__
+		private bool _warnedAboutTranslation;
+#endif
 
 		private static readonly TypedEventHandler<UIElement, BringIntoViewRequestedEventArgs> OnBringIntoViewRequestedHandler =
 			(UIElement sender, BringIntoViewRequestedEventArgs args) => sender.OnBringIntoViewRequested(args);
@@ -265,6 +268,19 @@ public Vector3 Translation
 				if (_translation != value)
 				{
 					_translation = value;
+
+#if !__SKIA__
+					if (!_warnedAboutTranslation &&
+						(_translation.X != 0 || _translation.Y != 0))
+					{
+						_warnedAboutTranslation = true;
+						if (this.Log().IsEnabled(LogLevel.Warning))
+						{
+							this.Log().LogWarning("Translation supports only Z-axis on this target.");
+						}
+					}
+#endif
+
 					UpdateShadow();
 					InvalidateArrange();
 				}

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

@@ -36,6 +36,7 @@ public partial class UIElement : DependencyObject, IVisualElement, IVisualElemen
 		private protected ContainerVisual _visual;
 		private Rect _lastFinalRect;
 		private Rect? _lastClippedFrame;
+		private Vector3 _lastTranslation;
 
 		public UIElement()
 		{
@@ -278,16 +279,21 @@ internal void ArrangeVisual(Rect finalRect, Rect? clippedFrame = default)
 
 			var oldFinalRect = _lastFinalRect;
 			var oldClippedFrame = _lastClippedFrame;
+			var oldTranslation = _lastTranslation;
 			_lastFinalRect = finalRect;
 			_lastClippedFrame = clippedFrame;
+			_lastTranslation = _translation;
 
 			var oldRect = oldFinalRect;
 			var newRect = finalRect;
 
 			var oldClip = oldClippedFrame;
 			var newClip = clippedFrame;
 
-			if (oldRect != newRect || oldClip != newClip || (_renderTransform?.FlowDirectionTransform ?? Matrix3x2.Identity) != GetFlowDirectionTransform())
+			if (oldRect != newRect ||
+				oldClip != newClip ||
+				oldTranslation != _translation ||
+				(_renderTransform?.FlowDirectionTransform ?? Matrix3x2.Identity) != GetFlowDirectionTransform())
 			{
 				if (
 					newRect.Width < 0