This hackery, by the way, was all inspired by John (or, Special, as he's more commonly known). He started blabbing on about how wonderful Windows 7 is (yet again), and I wondered whether KDE had this particular part of wonderfulness: 'aero snap'. I quickly discovered that it had parts of it ('pack window to X' direction shortcuts), but I also found out that they basically sucked, so I started researching how best to implement it that night. I didn't make a lot of progress - I'm still very new to kwin.
The next day, I talked to Martin - who has been most helpful in making me feel welcome to the kwin (and more widely, the KDE) family -- hi!
He happened to tell me that he'd already written a lot of the snap stuff, so hooray, it was there. The bit that he *hadn't* done, however, was the very bit that I wanted: hotkeys.
So after he committed his work, I got down and dirty and started hacking, and in short order, I had hotkeys.
I then took it a step further, and added in geometry saving, so that windows also get restored back to their original size after no longer being snapped (or 'quick tiled' as we call it in kwin land).
Night drew to a close, and it was still rather buggy and annoying in places, so when I got home from work the following day, I hacked some more, and that's where I am right now: kwin now has hotkey support *and* screen edge support for quick tiling ("aero snap") that works with maximized windows, saves geometry and restores it when un-tiled/maximized correctly, and much, much more.
All in all, I'm quite proud of what I've managed to achieve given my (so far) limited exposure to the kwin codebase, and also thanks to the rather ..unique.. way some of the geometry code is structured.
Hopefully I'll be useful in helping make some more sense out of all this as time goes by. ;)