I have zero experience with multiple displays & cocoa. Feel free to share any handy links, tutorials. What I need is this : I'm trying to fill all displays with a full screen, transparent window. What I'm afraid for, though, is that all the displays together don't necessarily form a rectangle, but have to touch somewhere.
What are your thoughts about this?
You would set up a window for each display that is not mirrored. The API you are looking for is "Quartz Display Services".
CGGetActiveDisplayList gives you a list of non-sleeping, non-mirrored, drawable displays.