Somewhat related, bitmap files (.bmp) store the image lines in bottom-to-top order, effectively putting (0,0) at the bottom-left.

It's the only image format I've ever seen that does that -- everyone else stores lines in top-to-bottom order, consistent with putting (0,0) at the top-left.

What do bitmap and excel have in common? :D

E.g. OpenGL normalized device coordinates have x=0,y=0 at screen center, with top left being x=-1,y=1. It's easier to reason with in many cases.

> I don't think I've ever seen a graphical system of any kind that didn't have 0,0 at the top-left corner of the monitor or viewport either, with positive x going right and positive y going down.

Is that because the electron beam in cathode ray tubes scanned from top left to bottom right?

OS/2's Presentation Manager had 0,0 at the bottom-left corner of the monitor.