@hhedberg:

Thanks, I will look into that as soon as I get a chance. If I find something that works along those lines, it might make the first question obsolete, although I'd still like to find an answer for that for when I'm not running fullscreen.

@kwotski:

You are right, in a real application you would probably just read out the window size when you get a resize event, but I consider this test app as just a hacky playground to learn about Xlib and EGL, both of which I haven't used before.