Don't round size in TextBlock when UseLayoutRounding is false (#18456)

* Don't round size when UselayoutRounding is false for TextBlock. Fixes #18423

* Added back size rounding

* Removed rounding again for the text size and fixed padding rounding in RenderCore

src/Avalonia.Controls/TextBlock.cs

@@ -604,8 +604,13 @@ namespace Avalonia.Controls
                 context.FillRectangle(background, new Rect(Bounds.Size));
             }
 
-            var scale = LayoutHelper.GetLayoutScale(this);
-            var padding = LayoutHelper.RoundLayoutThickness(Padding, scale);
+            var padding = Padding;
+            if (UseLayoutRounding)
+            {
+                var scale = LayoutHelper.GetLayoutScale(this);
+                padding = LayoutHelper.RoundLayoutThickness(padding, scale);
+            }
+
             var top = padding.Top;
             var textHeight = TextLayout.Height;
 
@@ -708,8 +713,14 @@ namespace Avalonia.Controls
 
         protected override Size MeasureOverride(Size availableSize)
         {
-            var scale = LayoutHelper.GetLayoutScale(this);
-            var padding = LayoutHelper.RoundLayoutThickness(Padding, scale);
+            var padding = Padding;
+
+            if (UseLayoutRounding)
+            {
+                var scale = LayoutHelper.GetLayoutScale(this);
+                padding = LayoutHelper.RoundLayoutThickness(Padding, scale);
+            }
+
             var deflatedSize = availableSize.Deflate(padding);
 
             if (_constraint != deflatedSize)
@@ -741,15 +752,17 @@ namespace Avalonia.Controls
             var textLayout = TextLayout;
 
             // The textWidth used here is matching that TextPresenter uses to measure the text.
-            var size = LayoutHelper.RoundLayoutSizeUp(new Size(textLayout.WidthIncludingTrailingWhitespace, textLayout.Height).Inflate(padding), 1);
-
-            return size;
+            return new Size(textLayout.WidthIncludingTrailingWhitespace, textLayout.Height).Inflate(padding);
         }
 
         protected override Size ArrangeOverride(Size finalSize)
         {
-            var scale = LayoutHelper.GetLayoutScale(this);
-            var padding = LayoutHelper.RoundLayoutThickness(Padding, scale);
+            var padding = Padding;
+            if (UseLayoutRounding)
+            {
+                var scale = LayoutHelper.GetLayoutScale(this);
+                padding = LayoutHelper.RoundLayoutThickness(Padding, scale);
+            }
 
             var availableSize = finalSize.Deflate(padding);
 

tests/Avalonia.Controls.UnitTests/TextBlockTests.cs

@@ -458,6 +458,80 @@ namespace Avalonia.Controls.UnitTests
             Assert.True(target.DesiredSize.Height > 0);
         }
 
+        [Fact]
+        public void TextBlock_With_UseLayoutRounding_True_Should_Round_DesiredSize()
+        {
+            using var app = UnitTestApplication.Start(TestServices.MockPlatformRenderInterface);
+
+            var target = new TextBlock { Text = "1980" };
+
+            target.Measure(new Size(double.PositiveInfinity, double.PositiveInfinity));
+
+            Assert.Equal(target.DesiredSize, new Size(40, 10));
+        }
+
+        [Fact]
+        public void TextBlock_With_UseLayoutRounding_True_Should_Round_Padding_And_DesiredSize()
+        {
+            using var app = UnitTestApplication.Start(TestServices.MockPlatformRenderInterface);
+
+            var target = new TextBlock { Text = "1980", Padding = new(2.25) };
+
+            target.Measure(new Size(double.PositiveInfinity, double.PositiveInfinity));
+
+            Assert.Equal(target.DesiredSize, new Size(44, 14));
+        }
+
+        [Fact]
+        public void TextBlock_With_UseLayoutRounding_False_Should_Not_Round_DesiredSize()
+        {
+            using var app = UnitTestApplication.Start(TestServices.MockPlatformRenderInterface);
+
+            var target = new TextBlock { Text = "1980", UseLayoutRounding = false };
+
+            target.Measure(new Size(double.PositiveInfinity, double.PositiveInfinity));
+
+            Assert.Equal(target.DesiredSize, new Size(40, 9.6));
+        }
+
+        [Fact]
+        public void TextBlock_With_UseLayoutRounding_False_Should_Not_Round_Bounds()
+        {
+            using var app = UnitTestApplication.Start(TestServices.MockPlatformRenderInterface);
+
+            var target = new TextBlock { Text = "1980", UseLayoutRounding = false };
+
+            target.Measure(new Size(double.PositiveInfinity, double.PositiveInfinity));
+            target.Arrange(new Rect(default, target.DesiredSize));
+
+            Assert.Equal(target.Bounds, new Rect(0, 0, 40, 9.6));
+        }
+
+        [Fact]
+        public void TextBlock_With_UseLayoutRounding_False_Should_Not_Round_Padding_In_MeasureOverride()
+        {
+            using var app = UnitTestApplication.Start(TestServices.MockPlatformRenderInterface);
+
+            var target = new TextBlock { Text = "1980", UseLayoutRounding = false, Padding = new(2.25) };
+
+            target.Measure(new Size(double.PositiveInfinity, double.PositiveInfinity));
+
+            Assert.Equal(target.DesiredSize, new Size(44.5, 14.1));
+        }
+
+        [Fact]
+        public void TextBlock_With_UseLayoutRounding_False_Should_Not_Round_Padding_In_ArrangeOverride()
+        {
+            using var app = UnitTestApplication.Start(TestServices.MockPlatformRenderInterface);
+
+            var target = new TextBlock { Text = "1980", UseLayoutRounding = false, Padding = new(2.25) };
+
+            target.Measure(new Size(double.PositiveInfinity, double.PositiveInfinity));
+            target.Arrange(new Rect(default, target.DesiredSize));
+
+            Assert.Equal(target.Bounds, new Rect(0, 0, 44.5, 14.1));
+        }
+
         private class TestTextBlock : TextBlock
         {
             public Size Constraint => _constraint;