UIColor+Interpolation

UIColor+Interpolation.m

+ (UIColor *)colorBetweenColor:(UIColor *)color1
                      andColor:(UIColor *)color2
                    atProgress:(CGFloat)progress
{
    CGFloat r1,g1,b1,a1,r2,g2,b2,a2;
    [color1 getRed:&r1 green:&g1 blue:&b1 alpha:&a1];
    [color2 getRed:&r2 green:&g2 blue:&b2 alpha:&a2];
    return [UIColor colorWithRed:r1+(r2-r1)*progress
                           green:g1+(g2-g1)*progress
                            blue:b1+(b2-b1)*progress
                           alpha:a1+(a2-a1)*progress];
}