iOS实现点击微信头像(放大、缩放、保存)效果

先来看看实现效果（GIF）：

实现思路：

直接自定义 UIView（CYPhotoPreviewer），为了实现双击缩放，可以实现 UIScrollViewDelegate 对应的方法。如果需要模糊背景，可以在自定义的 UIView 中先添加模糊背景，再添加 UIScrollView，继而在 UIScrollView 中添加图片容器，这个容器就是要显示的图片的 superView，代码一目了然：

- (void)setup {
 
 self.frame = [UIScreenmainScreen].bounds;
 self.backgroundColor = [UIColorclearColor];
 
 UITapGestureRecognizer *singleTap = [[UITapGestureRecognizeralloc] initWithTarget:selfaction:@selector(singleTap:)];
 [self addGestureRecognizer:singleTap];
 
 UITapGestureRecognizer *doubleTap = [[UITapGestureRecognizeralloc] initWithTarget:selfaction:@selector(doubleTap:)];
 doubleTap.numberOfTapsRequired = 2;
 [singleTaprequireGestureRecognizerToFail:doubleTap];
 [self addGestureRecognizer:doubleTap];
 
 UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizeralloc] initWithTarget:selfaction:@selector(longPress:)];
 [self addGestureRecognizer:longPress];
 
 // 设置模糊背景
 self.blurBackground = [[UIVisualEffectViewalloc] initWithEffect:[UIBlurEffecteffectWithStyle:UIBlurEffectStyleExtraLight]];
 self.blurBackground.frame = self.frame;
 [self addSubview:self.blurBackground];
 
 // 设置 UIScrollView 相关属性
 self.scrollView = [[UIScrollViewalloc] initWithFrame:[UIScreenmainScreen].bounds];
 self.scrollView.delegate = self;
 self.scrollView.bouncesZoom = YES;
 self.scrollView.maximumZoomScale = 3.0;
 self.scrollView.multipleTouchEnabled = YES;
 self.scrollView.alwaysBounceVertical = NO;
 self.scrollView.showsVerticalScrollIndicator = NO;
 self.scrollView.showsHorizontalScrollIndicator = NO;
 [self addSubview:self.scrollView];
 
 // containerView
 self.containerView = [[UIViewalloc] init];
 [self.scrollViewaddSubview:self.containerView];
 
 // imageView
 self.imageView = [[UIImageViewalloc] init];
 self.imageView.clipsToBounds = YES;
 self.imageView.backgroundColor = [UIColorcolorWithWhite:1.0 alpha:0.5];
 [self.containerViewaddSubview:self.imageView];
}