Fixes geometry render bounds when curves are present

[MrJul]

What does the pull request do?

This PR fixes the render bounds of geometries containing curves.

What is the current behavior?

The render bounds are too large, containing the curve control points.

Example:

At the top is DrawingImage with incorrect bounds, having the height almost twice as high as necessary.
At the bottom is a Path with correct bounds (Path has its own bounds calculation).

Show code

<StackPanel Orientation="Vertical" Spacing="20" Margin="20">

  <Border HorizontalAlignment="Left" Background="Blue">
    <Image Width="128">
      <DrawingImage>
        <DrawingImage.Drawing>
          <GeometryDrawing Brush="Yellow" Geometry="{StaticResource Geometry}" />
        </DrawingImage.Drawing>
      </DrawingImage>
    </Image>
  </Border>

  <Border HorizontalAlignment="Left" Background="Blue">
    <Path Width="128" Fill="Yellow" Data="{StaticResource Geometry}" />
  </Border>

</StackPanel>

Geometry:

<Geometry x:Key="Geometry">M0,0 A128,128 0 0 0 128,0</Geometry>

What is the updated/expected behavior with this PR?

The bounds are correctly computed.

Result:

How was the solution implemented (if it's not obvious)?

SKPath.TightBounds is used instead of SKPath.Bounds.
(These were the only two usages of Bounds, other types using SKPath were already using TightBounds.)

A unit test has been added.
Note that an existing unit test has been modified, because it used round line caps, which caused the same problem.

[MrJul]

The new test was passing on Windows but failing on Linux and macOS due to a floating point rounding error at the 6th decimal (17.14875030517578 vs 17.148752212524414).

The tests were already using a tolerance of 0.001, but still checked for a perfect Equals match right after. This has been changed to use xUnit's Assert.Equal(x, y, tolerance) instead.

[avaloniaui-bot]

You can test this PR using the following package version. 11.2.999-cibuild0051418-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

[avaloniaui-bot]

You can test this PR using the following package version. 11.2.999-cibuild0051777-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]