This PR updates the test image to be more usable on non rectangular displays. The previous version of the test image did only draw white markers in the corners of this display, which weren't visible on round and rounded rectangle displays. The new version draws a solid 1 px white border and leaves some space between the border and the color bars to make the border more visible.
I've also added some docs that describe the expected output and what settings need to be changed if the image isn't displayed correctly.
This PR updates the test image to be more usable on non rectangular displays. The previous version of the test image did only draw white markers in the corners of this display, which weren't visible on round and rounded rectangle displays. The new version draws a solid 1 px white border and leaves some space between the border and the color bars to make the border more visible.
I've also added some docs that describe the expected output and what settings need to be changed if the image isn't displayed correctly.