WinUI3: Rotation in Manipulation events is wrong

[dotMorten]

Describe the bug
When using the ManipulationDelta event to track rotation changes, the values reported are way too large. Rotating your fingers reports a value exactly 180/Pi too large.

Steps to reproduce the bug

1. Add the following XAML to the view:

        <Border Background="Red" Width="300" Height="300" 
                ManipulationMode="All"
                ManipulationStarted="Border_ManipulationStarted"
                ManipulationDelta="Border_ManipulationDelta"
                ManipulationCompleted="Border_ManipulationCompleted">
            <TextBlock Text="Rotate me" x:Name="status" Foreground="White" HorizontalAlignment="Center" VerticalAlignment="Center" />
        </Border>

2. Add the following code-behind:

        private double angle = 0;
        private void Border_ManipulationStarted(object sender, ManipulationStartedRoutedEventArgs e)
        {
            angle = 0;
            status.Text = "Begin";
        }

        private void Border_ManipulationDelta(object sender, ManipulationDeltaRoutedEventArgs e)
        {
            angle += e.Delta.Rotation;
            status.Text = $"Cumulative (sum of deltas): {angle}\nDelta: {e.Delta.Rotation}\nCumulative: {e.Cumulative.Rotation}";
        }

        private void Border_ManipulationCompleted(object sender, ManipulationCompletedRoutedEventArgs e)
        {
            status.Text += "\nCompleted!";
        }

3. Run the application on a touch screen, and rotate with two fingers over the red box.
4. Observe the values reported doesn't match what you're doing (all 3 values written are wrong of about 17-18 times larger than expected).

Expected behavior
Rotation values reported matches actual user input

Screenshots

Version Info

NuGet package version:
[Microsoft.WinUI 3.0.0-preview3.201113.0]

Windows app type:

UWP	Win32
Yes	Yes

Windows 10 version	Saw the problem?
Insider Build (xxxxx)
May 2020 Update (19041)	Yes
November 2019 Update (18363)	Yes
May 2019 Update (18362)
October 2018 Update (17763)
April 2018 Update (17134)
Fall Creators Update (16299)
Creators Update (15063)

Device form factor	Saw the problem?
Desktop	Yes (Surface Book 2 & Surface Go 1
Xbox
Surface Hub
IoT

Additional context

[StephenLPeters]

@codendone FYI

[codendone]

Thanks for reporting. As you found, there is a place where we're incorrectly converting radians to degrees when the value was already in degrees.

[dotMorten]

@codendone Any update on this? Sounds like an easy fix, and some might consider this a breaking behavior down the line once it's v1.0

[codendone]

I agree, and I had hoped we'd get to this sooner. This is scheduled to be fixed for 0.8, and hopefully will be completed around the end of April.

[anawishnoff]

This has been fixed in the most recent release of WinUI 3 (Windows App SDK 0.8), so I'm closing this issue. Feel free to re-open if the issue still persists.

[dotMorten]

sorry forgot to close this when I confirmed the fix last week. Thank you!