UIColor转RGB值的方法

 UIColor *redColor = [UIColor redColor];
 const CGFloat *redRGB = [self RGBFromColor:redColor];
 NSLog(@"red: %f,green: %f,blue: %f",redRGB[0],redRGB[1],redRGB[2]);
 //上行代码将会输出:red: 1.000000,green: 0.000000,blue: 0.000000

- (CGFloat *)RGBFromColor:(UIColor *)color{
    return  (CGFloat *)CGColorGetComponents(color.CGColor);
}