Comment by jefftk

It all depends on how much context the reader has. For some audiences a comment explaining bounding boxes would be helpful; for others your example comment adds nothing that isn't immediately apparent from the code.

Part of figuring out a reasonable level of commenting (and even variable naming) is a solid understanding of your audience. When in doubt aiming low is good practice, but keep in mind that this was 2D graphics software written at a 2D graphics software company.