> What is the "01" in the upper byte for? > > I did not know that was used for anything. >
The color format is xxrrggbb where xx means the uppers are reserved. If xx is 00, then the lowers form the 24 bit rgb value. If nonzero, then something else is going on and either the color is invalid or it has a symbolic meaning, which is what the 01 indicates. And the other upper byte values are still reserved for future use, like alpha channel for example. Anyway, 01yyyyyy means we can have 2^24 symbolic colors, and so far Apple and MS have used about fifty and the most common six are in the color picker. Greg Mckaskle
