#import <UIKit/UIKit.h>
 
@interface ViewController : UIViewController
 
@end
 
#import "ViewController.h"
#import "HWButton.h"
 
#define mainW [UIScreen mainScreen].bounds.size.width
#define mainH [UIScreen mainScreen].bounds.size.height
 
@interface ViewController ()
 
@end
 
@implementation ViewController
 
- (void)viewDidLoad {
  [super viewDidLoad];
 
  self.view.backgroundColor = [UIColor blackColor];
 
  //創建控件
  [self creatButton];
}
 
- (void)creatButton
{
  HWButton *button = [[HWButton alloc] initWithFrame:CGRectMake(mainW * 0.5 - 60, mainH - 100, 120, 72) maxLeft:100 maxRight:100 maxHeight:300];
  [button setImage:[UIImage imageNamed:@"button"] forState:UIControlStateNormal];
  button.images = @[[UIImage imageNamed:@"Circle 1"], [UIImage imageNamed:@"Circle 2"], [UIImage imageNamed:@"Circle 3"], [UIImage imageNamed:@"Hero"]];
  button.duration = 10;
  [button addTarget:self action:@selector(buttonOnClick:) forControlEvents:UIControlEventTouchUpInside];
  [self.view addSubview:button];
}
 
- (void)buttonOnClick:(HWButton *)btn
{
  [btn generateBubbleInRandom];
}
 
@end

#import <UIKit/UIKit.h>
 
@interface HWButton : UIButton
 
@property (nonatomic, assign) CGFloat maxLeft;
@property (nonatomic, assign) CGFloat maxRight;
@property (nonatomic, assign) CGFloat maxHeight;
@property (nonatomic, assign) CGFloat duration;
@property (nonatomic, strong) NSArray *images;
 
- (instancetype)initWithFrame:(CGRect)frame maxLeft:(CGFloat)maxLeft maxRight:(CGFloat)maxRight maxHeight:(CGFloat)maxHeight;
 
- (void)generateBubbleWithImage:(UIImage *)image;
 
- (void)generateBubbleInRandom;
 
@end
 
#import "HWButton.h"
 
@implementation HWButton
{
  CGPoint _startPoint;
  CGFloat _maxWidth;
  NSMutableSet *_recyclePool;
  NSMutableArray *_array;
}
 
- (instancetype)initWithFrame:(CGRect)frame maxLeft:(CGFloat)maxLeft maxRight:(CGFloat)maxRight maxHeight:(CGFloat)maxHeight
{
  self = [super initWithFrame:frame];
  if (self) {
    _maxHeight = maxHeight;
    _maxLeft  = maxLeft;
    _maxRight = maxRight;
    
    [self initData];
  }
  return self;
}
 
- (id)initWithCoder:(NSCoder *)aDecoder
{
  self = [super initWithCoder:aDecoder];
  if (self) {
    [self initData];
  }
  return self;
}
 
- (void)initData
{
  _array = @[].mutableCopy;
  _recyclePool = [NSMutableSet set];
}
 
- (void)generateBubbleInRandom
{
  CALayer *layer;
  
  if (_recyclePool.count > 0) {
    layer = [_recyclePool anyObject];
    
    [_recyclePool removeObject:layer];
    
  }else {
    UIImage *image = self.images[arc4random() % self.images.count];
    
    layer = [self createLayerWithImage:image];
  }
  
  [self.layer addSublayer:layer];
  [self generateBubbleWithCAlayer:layer];
}
 
- (void)generateBubbleWithImage:(UIImage *)image
{
  CALayer *layer = [self createLayerWithImage:image];
  
  [self.layer addSublayer:layer];
  [self generateBubbleWithCAlayer:layer];
}
 
- (void)generateBubbleWithCAlayer:(CALayer *)layer
{
  _maxWidth = _maxLeft + _maxRight + self.bounds.size.width;
  
  _startPoint = CGPointMake(self.frame.size.width / 2, 0);
  
  CGPoint endPoint = CGPointMake(_maxWidth * [self randomFloat] - _maxLeft, -_maxHeight);
  CGPoint controlPoint1 = CGPointMake(_maxWidth * [self randomFloat] - _maxLeft, -_maxHeight * 0.2);
  CGPoint controlPoint2 = CGPointMake(_maxWidth * [self randomFloat] - _maxLeft, -_maxHeight * 0.6);
  
  CGMutablePathRef curvedPath = CGPathCreateMutable();
  CGPathMoveToPoint(curvedPath, NULL, _startPoint.x, _startPoint.y);
  CGPathAddCurveToPoint(curvedPath, NULL, controlPoint1.x, controlPoint1.y, controlPoint2.x, controlPoint2.y, endPoint.x, endPoint.y);
  
  CAKeyframeAnimation *keyFrame = [CAKeyframeAnimation animation];
  keyFrame.keyPath = @"position";
  keyFrame.path = CFAutorelease(curvedPath);
  keyFrame.duration = self.duration;
  keyFrame.calculationMode = kCAAnimationPaced;
  
  [layer addAnimation:keyFrame forKey:@"keyframe"];
  
  CABasicAnimation *scale = [CABasicAnimation animation];
  scale.keyPath = @"transform.scale";
  scale.toValue = @1;
  scale.fromValue = [NSValue valueWithCATransform3D:CATransform3DMakeScale(0.1, 0.1, 0.1)];
  scale.duration = 0.5;
  
  CABasicAnimation *alpha = [CABasicAnimation animation];
  alpha.keyPath = @"opacity";
  alpha.fromValue = @1;
  alpha.toValue = @0.1;
  alpha.duration = self.duration * 0.4;
  alpha.beginTime = self.duration - alpha.duration;
  
  CAAnimationGroup *group = [CAAnimationGroup animation];
  group.animations = @[keyFrame, scale, alpha];
  group.duration = self.duration;
  group.delegate = self;
  group.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut];
  group.fillMode = kCAFillModeForwards;
  group.removedOnCompletion = NO;
  [layer addAnimation:group forKey:@"group"];
  
  [_array addObject:layer];
}
 
- (CGFloat)randomFloat
{
  return (arc4random() % 100)/100.0f;
}
 
- (CALayer *)createLayerWithImage:(UIImage *)image
{
  CGFloat scale = [UIScreen mainScreen].scale;
  CALayer *layer = [CALayer layer];
  layer.frame  = CGRectMake(0, 0, image.size.width / scale, image.size.height / scale);
  layer.contents = (__bridge id)image.CGImage;;
  return layer;
}
 
- (void)animationDidStop:(CAAnimation *)anim finished:(BOOL)flag
{
  if (flag) {
    CALayer *layer = [_array firstObject];
    [layer removeAllAnimations];
    [layer removeFromSuperlayer];
    [_array removeObject:layer];
    [_recyclePool addObject:layer];
  }
}
 
@end