Personally I'd consider SongGenie a bad example of app skinning/theming.
The window's top gloss effect is way overdone and the overall theme contrast is way too harsh to be pleasant to the eyes.
Here are some simple rules of thumb for custom-theming OS X apps:
- Don't do it (unless there really is no way around it).
- Don't theme UIs for the sake of theming!
- If you have to do it, make it subtle! (don't force the the user to re-learn your UI)
- Make your theme match the system's overall style. (matte vs. glossy, etc.)
- See 1.)
Especially for point 4) SongGenie is kind of a worst case scenario: the app's style (apart from being utterly overdone) does not match the rather matte (vs. Windows 7's glossy) look os OS X. To give an example of properly style-conforming theming take Permute.app
So if you really, really want to (wait, if you really "must") do theming, then take a look at BGHUDAppKit for a technical starting point on how such thing can be done. But keep in mind that this project has some pretty bad performance optimizations. (massive method call redundancies and hardly any caching of such, or optimizations at all)
Again: Don't do it. Unless you're both a good dev and an even better UI designer.
And being a dev, odds are against you on the latter.
Alternatively to BGHUDAppKit, you might want to look at BWToolKit's (yet few) themed HUD controls.
UI design is to apps what typography is to print/writing:
»Good typography is what may have been a good servant, always at your service and yet not noticeable, inconspicuous, but a prerequisite of well-being, silent, smooth.«
Jan Tschichold
Original:
»Gute Typographie ist so, wie ein
guter Diener gewesen sein mag: da und
doch nicht bemerkbar; unauffällig,
aber eine Voraussetzung des
Wohlbefindens, lautlos, geschmeidig.«
Jan Tschichold