A XAML Radial Gauge Custom Control for UWP that is partially drawn by the Composition API.
A blog post that explains the code is right here: https://xamlbrewer.wordpress.com/2016/01/23/building-a-custom-uwp-control-with-xaml-and-the-composition-api/.
There's a newer version of this control in the UWP Community Toolkit: https://github.com/Microsoft/UWPCommunityToolkit.