As a developer it is impossible to clip a rotated gui.
Often in gui development you will have elements that are mirrored images of each other, such as page buttons. Right now you have to upload two images - one for each of these elements, but it is often the case that one image is just a rotated version of another image. So it would be much easier for developers and also lighter on loading times to be able to just rotate the image.
It actually used to be the case that guis rotated in multiples of 180 degrees would be clipped correctly, but that was changed at some point. Making guis rotated in multiples of 90 degrees shouldn’t be overly difficult because the guis would still be axis-aligned and therefore work with the current clipping system.
