I want to do something like this, but I cannot get a cooperative syntax.
static const UIColor *colorNavbar = [UIColor colorWithRed: 197.0/255.0 green: 169.0/255.0 blue: 140.0/255.0 alpha: 1.0];
I suppose that I could define macros, but they are ugly.
I like to use categories to extend classes with new methods for this sort of thing. Here's an excerpt of code I just wrote today:
@implementation UIColor (Extensions)
+ (UIColor *)colorWithHueDegrees:(CGFloat)hue saturation:(CGFloat)saturation brightness:(CGFloat)brightness {
return [UIColor colorWithHue:(hue/360) saturation:saturation brightness:brightness alpha:1.0];
}
+ (UIColor *)aquaColor {
return [UIColor colorWithHueDegrees:210 saturation:1.0 brightness:1.0];
}
+ (UIColor *)paleYellowColor {
return [UIColor colorWithHueDegrees:60 saturation:0.2 brightness:1.0];
}
@end
Now in code I can do things like:
self.view.backgroundColor = highlight? [UIColor paleYellowColor] : [UIColor whitecolor];
and my own defined colors fit right in alongside the system-defined ones.
(Incidentally, I am starting to think more in terms of HSB than RGB as I pay more attention to colors.)
UPDATE regarding precomputing the value: My hunch is that it's not worth it. But if you really wanted, you could memoize the values with static variables:
+ (UIColor *)paleYellowColor {
static UIColor *color = nil;
if (!color) color = [UIColor colorWithHueDegrees:60 saturation:0.2 brightness:1.0];
return color;
}
You could make a macro do do the memoizing, too.