UIColor Linear Interpolation (lerp)

UIColor+Lerp.m

+ (UIColor *)colorLerpFrom:(UIColor *)start to:(UIColor *)end withProgress:(CGFloat)t
{
    // TODO: Interpolate in HSB space instead of RGB
    t = MAX(0, MIN(1, t));
    
    CGFloat redA, greenA, blueA, alphaA;
    [start getRed:&redA green:&greenA blue:&blueA alpha:&alphaA];
    
    CGFloat redB, greenB, blueB, alphaB;
    [end getRed:&redB green:&greenB blue:&blueB alpha:&alphaB];
    
    CGFloat r = lerp(redA, redB, t);
    CGFloat g = lerp(greenA, greenB, t);
    CGFloat b = lerp(blueA, blueB, t);
    CGFloat a = lerp(alphaA, alphaB, t);
    
    return [UIColor colorWithRed:r green:g blue:b alpha:a];
}