#import "UIView+Bounce.h"
@implementation UIView (Bounce)
+ (CAKeyframeAnimation *)dockBounceAnimationWithViewHeight:(CGFloat)viewHeight {
    NSUInteger const kNumFactors    = 23;
    CGFloat const kFactorsPerSec    = 120.0f;
    CGFloat const kFactorsMaxValue  = 128.0f;

    CGFloat factors[kNumFactors]    = { 0,  83, 100, 114, 124, 138, 156, 184, 156, 138, 124, 114, 100, 83, 32, 0, 0, 18, 28, 32, 28, 18, 0 };

    NSMutableArray *transforms = [NSMutableArray array];

    for (NSUInteger i = 0; i < kNumFactors; i++) {
        CGFloat positionOffset  = factors[i] / kFactorsMaxValue * viewHeight;
        CATransform3D transform = CATransform3DMakeTranslation(0.0f, -positionOffset, 0.0f);

        [transforms addObject:[NSValue valueWithCATransform3D:transform]];
    }

    CAKeyframeAnimation *animation = [CAKeyframeAnimation animationWithKeyPath:@"transform"];
    animation.repeatCount           = 1;
    animation.duration              = kNumFactors * 1.0f / kFactorsPerSec;
    animation.fillMode              = kCAFillModeForwards;
    animation.values                = transforms;
    animation.removedOnCompletion   = YES; // final stage is equal to starting stage
    animation.autoreverses          = NO;

    return animation;
}
- (void)bounce:(float)bounceFactor {
    CGFloat midHeight = self.frame.size.height * bounceFactor;
    CAKeyframeAnimation *animation = [[self class] dockBounceAnimationWithViewHeight:midHeight];
    [self.layer addAnimation:animation forKey:@"bouncing"];
}
@end