clearPicture
Takes the picture off (#530): the frame waiting for the worker goes, a frame the worker is converting is not drawn, and the worker blanks the Surface. Nothing here waits, because the engine calls this from its own loop.
Takes the picture off (#530): the frame waiting for the worker goes, a frame the worker is converting is not drawn, and the worker blanks the Surface. Nothing here waits, because the engine calls this from its own loop.