iOS实现点击微信头像(放大、缩放、保存)效果

- (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];
}

- (void)previewFromImageView:(UIImageView *)fromImageViewinContainer:(UIView *)container {
 _fromImageView = fromImageView;
 fromImageView.hidden = YES;
 [containeraddSubview:self]; // 将 CYPhotoPreviewer 添加到 container 上
 
 self.containerView.origin = CGPointZero;
 self.containerView.width = self.width; // containerView 的宽度是屏幕的宽度
 
 UIImage *image = fromImageView.image;
 
 // 计算 containerView 的高度
 if (image.size.height / image.size.height > self.height / self.width) {
 self.containerView.height = floor(image.size.height / (image.size.width / self.width));
 } else {
 CGFloatheight = image.size.height / image.size.width * self.width;
 if (height self.height && self.containerView.height - self.height

- (void)dismiss {
 [UIViewanimateWithDuration:0.18 delay:0.0 options:UIViewAnimationOptionCurveEaseInOutanimations:^{
 CGRectfromRect = [self.fromImageViewconvertRect:self.fromImageView.boundstoView:self.containerView];
 self.imageView.contentMode = self.fromImageView.contentMode;
 self.imageView.frame = fromRect;
 self.blurBackground.alpha = 0.01;
 } completion:^(BOOL finished) {
 [UIViewanimateWithDuration:0.10 delay:0 options:UIViewAnimationOptionCurveEaseInOutanimations:^{
 self.fromImageView.hidden = NO;
 self.alpha = 0;
 } completion:^(BOOL finished) {
 [self removeFromSuperview];
 }];
 }];
}

- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView{
 return self.containerView;
}
 
- (void)scrollViewDidZoom:(UIScrollView *)scrollView {
 UIView *subView = self.containerView;
 
 CGFloatoffsetX = (scrollView.bounds.size.width > scrollView.contentSize.width)?
 (scrollView.bounds.size.width - scrollView.contentSize.width) * 0.5 : 0.0;
 
 CGFloatoffsetY = (scrollView.bounds.size.height > scrollView.contentSize.height)?
 (scrollView.bounds.size.height - scrollView.contentSize.height) * 0.5 : 0.0;
 
 subView.center = CGPointMake(scrollView.contentSize.width * 0.5 + offsetX,
  scrollView.contentSize.height * 0.5 + offsetY);
}
 
- (void)doubleTap:(UITapGestureRecognizer *)recognizer {
 if (self.scrollView.zoomScale > 1.0) {
 [self.scrollViewsetZoomScale:1.0 animated:YES];
 } else {
 CGPointtouchPoint = [recognizerlocationInView:self.imageView];
 CGFloatnewZoomScale = self.scrollView.maximumZoomScale;
 CGFloatxSize = self.width / newZoomScale;
 CGFloatySize = self.height / newZoomScale;
 [self.scrollViewzoomToRect:CGRectMake(touchPoint.x - xSize / 2, touchPoint.y - ySize / 2, xSize, ySize) animated:YES];
 }
}

- (void)longPress:(UILongPressGestureRecognizer *)recognizer {
 
 // 为了避免弹警告：Warning: Attempt to present on which is already presenting ，最好加入状态判断
 if (recognizer.state == UIGestureRecognizerStateBegan) {
 UIAlertController *alertController = [UIAlertControlleralertControllerWithTitle:@"QuoraDots" message:nilpreferredStyle:UIAlertControllerStyleActionSheet];
 
 [alertControlleraddAction:[UIAlertActionactionWithTitle:@"保存" style:UIAlertActionStyleDefaulthandler:nil]];
 [alertControlleraddAction:[UIAlertActionactionWithTitle:@"取消" style:UIAlertActionStyleCancelhandler:nil]];
 
 UIViewController *vc = self.viewController;
 [vcpresentViewController:alertControlleranimated:YEScompletion:nil];
 }
}