iPhone生成颜色
CGColorSpaceRef rgb = CGColorSpaceCreateDeviceRGB();
const CGFloat myColor[] = {0.90625, 0.80, 0.80, 1.0};
//CGColorCreate(rgb, myColor) to return a CGColorRef.
label.backgroundColor = [[UIColor alloc] initWithCGColor:CGColorCreate(rgb, myColor)];
label.textColor = [[UIColor alloc] initWithRed:0.33 green:0.33 blue:0.33 alpha:1.0];