- Account for the render target transform when snapping, so images drawn under
translated or scaled content (TextBox, Menu, EmojiPanel) still land on the
device pixel grid; skip snapping for non-axis-aligned transforms or invalid DPI.
- Move the clip together with the snapped image so None/UniformToFill no longer
shave half a pixel off an edge.
- With ImageStretch::None, crop to the bounds via a source rect instead of
squeezing the whole bitmap in.
- Make the test fixture exception-safe, tolerate an existing MTA apartment, give
the test image an opaque border, and cover transforms, clipping and cropping.
fanlusky