Hacker News Reader

Have you gone down the rabbit hole of why the y coordinate is inverted in many computer graphics? :D

My first programming language was Ti-BASIC where screen coordinates worked with y=0 at the top. A natural choice given how the OS worked. I used it to cheat on math tests, so the two never felt like separate worlds to me and I understood the reason for both.

As for phi and theta, it just seems so arbitrary.

It's because CRT displays draw from top to bottom, right?

Largely that seems to be the consensus, yes.

I think it's more because printers (used to) print going down. I don;t see why it would matter in the least that crts draw the top first, if that is indeed the case. But for old printers where the paper is continuous, down is "forward" and there is no going back.

I think the printers and the old monitors reason are basically the same? Scanlines used to be a "you have now to set this pixel, if you missed it, you get next scan." It is an oddly accurate mental model to think of the screen as printing an image every scan.

Reply on news.ycombinator.com