Xcode- iOS Animation RBBCustomAnimation

RBBCustomAnimation

Use RBBCustomAnimation to create arbitrary animations by passing in an RBBAnimationBlock:

RBBCustomAnimation *rainbow = [RBBCustomAnimation animationWithKeyPath:@"backgroundColor"];

rainbow.animationBlock = ^(CGFloat elapsed, CGFloat duration) {
    UIColor *color = [UIColor colorWithHue:elapsed / duration
                                saturation:1
                                brightness:1
                                     alpha:1];

    return (id)color.CGColor;
};

The arguments of the block are the current position of the animation as well as its total duration.