[BUG] [Windows] UniformItemsLayout item positioning not correct #1553 (…

…#1566)

Co-authored-by: Brandon Minnick <[email protected]>

src/CommunityToolkit.Maui.Core/Layouts/UniformItemsLayoutManager.shared.cs

@@ -30,10 +30,15 @@ public override Size ArrangeChildren(Rect rectangle)
 		var width = rectangle.Width - uniformItemsLayout.Padding.HorizontalThickness;
 		var visibleChildren = uniformItemsLayout.Where(x => x.Visibility == Visibility.Visible).ToArray();
 
+		if (visibleChildren.Length == 0 || width == 0)
+		{
+			return rectangle.Size;
+		}
+
 		var columns = GetColumnsCount(visibleChildren.Length, width);
 		var rows = GetRowsCount(visibleChildren.Length, columns);
 
-		var boundsWidth = columns == 0 ? 0 : width / columns;
+		var boundsWidth = width / columns;
 		var boundsHeight = childHeight;
 		var bounds = new Rect(0, 0, boundsWidth, boundsHeight);
 		var count = 0;
@@ -51,7 +56,7 @@ public override Size ArrangeChildren(Rect rectangle)
 			}
 		}
 
-		return bounds.Size;
+		return rectangle.Size;
 	}
 
 	/// <summary>

src/CommunityToolkit.Maui.UnitTests/Layouts/UniformItemsLayoutTests.cs

@@ -99,14 +99,14 @@ public void MaxRowsArrangeChildrenUniformItemsLayout()
 	[Fact]
 	public void ArrangeChildrenUniformItemsLayout()
 	{
-		var expectedSize = new Size(childWidth, childHeight);
-		uniformChild = new TestView(expectedSize);
+		var childSize = new Size(childWidth, childHeight);
+		uniformChild = new TestView(childSize);
 		uniformItemsLayout.CrossPlatformMeasure(double.PositiveInfinity, double.PositiveInfinity);
 		var rect = new Rect(0, 0, childWidth * childCount, childHeight * childCount);
 		uniformItemsLayout.Layout(rect);
 		var actualSize = uniformItemsLayout.CrossPlatformArrange(rect);
 
-		Assert.Equal(expectedSize, actualSize);
+		Assert.Equal(childSize * childCount, actualSize);
 	}
 
 	class TestView : View