How to know if a NSWindow is fullscreen in Mac OS X Lion?

Question

I guess I should check if [NSApplication presentationOptions] contains NSFullScreenModeApplicationPresentationOptions, but how do I achieve that?

Answer 1

The way I handled it in pre-10.7 (where neither NSApplicationPresentationFullScreen nor NSFullScreenWindowMask was available) was to check

if ([mainWindow frame].size.height == [[mainWindow screen] frame].size.height)
{
    // window is fullscreen
}

and this piece of really old code seem to still work not only on "Lion" but also on today's - at the time of writing 10.14.x - OS.