Comment 5 for bug 669628

Okay, this should be working on all platforms. I changed the GUI positioning from manual "put it in the middle of the screen" to using a QHBoxLayout, which does the same thing automatically. This made the fullscreen code ridiculously simple. I was dragging the window size around (this has been possible since uglyduckling was merged) and realized I could now maximize mixxx and have it very much like fullscreen (skin-matching background, centered GUI) but with still having access to other windows and the taskbar. I decided I liked this enough that I coded a bit around it and now the whole operation works quite nicely. The only real problem that I've found is that on x11, we can't seem to know when we're maximized so we can't re-maximize the GUI after a skin change but that's hardly a deal breaker.

If I need extra justification for this mini-feature. it also solves a problem I have with fullscreen where, when compositing is enabled in kwin, the whole GUI flashes whenever I open a menu or a tooltip appears. Super annoying, but doesn't happen when maximized, so it gives me (and surely someone else out there using mixxx with compositing on linux with whatever highly popular Intel GPU I have) something very much like fullscreen.

I am going to leave this "in progress" till I boot over to Windows and make sure I haven't broken anything. Unfortunately, I don't have a Mac to test on so that platform has gone utterly neglected with this bugfix.