单击图片放大，浏览图片细节，之后再单击回到原始页面，

如果在浏览细节时候，双击图片 会局部放大，也可以双手拖拽放大，

newImage.gif

代码参考

#import "TransImageTool.h"

#define kSCREEN_WIDTH ([UIScreen mainScreen].bounds.size.width)

#define kSCREEN_HEIGHT ([UIScreen mainScreen].bounds.size.height)

#define kMaxZoom 3

@interface TransImageTool ()

@property (nonatomic, assign) CGFloat width;

@property (nonatomic, assign) CGFloat height;

@property (nonatomic, assign) BOOL isTwiceTaping;

@property (nonatomic, assign) BOOL isDoubleTapingForZoom;

@property (nonatomic, assign) CGFloat currentScale;

@property (nonatomic, assign) CGFloat offsetY;

@property (nonatomic, assign) CGFloat touchX;

@property (nonatomic, assign) CGFloat touchY;

@property (nonatomic, strong) UIImageView *transImageView;

@property (nonatomic, strong) UIScrollView *scrollView;

@property (nonatomic, strong) UIView *backView;

@property (nonatomic, strong) UIButton *userBtn ;

@property (nonatomic, strong) UIView *userBtnContainer ;

@end

static CGRect oldframe;

@implementation TransImageTool

- (void)showImage:(UIImageView *)avatarImageView{

UIImage *image = avatarImageView.image;

UIWindow *window = [UIApplication sharedApplication].keyWindow;

oldframe = [avatarImageView convertRect:avatarImageView.bounds toView:window];

UIImageView *imageView = [[UIImageView alloc]initWithFrame:oldframe];

imageView.image = image;

self.transImageView = imageView;

UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, kSCREEN_WIDTH, kSCREEN_HEIGHT)];

scrollView.delegate = self;

scrollView.backgroundColor = [UIColor blackColor];

scrollView.maximumZoomScale = 5.0;

CGFloat ratio = _width / _height * kSCREEN_HEIGHT / kSCREEN_WIDTH;

CGFloat min = MIN(ratio, 1.0);

scrollView.minimumZoomScale = min;

self.scrollView = scrollView;

UITapGestureRecognizer *onetap = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(hideImage:)];

[self.scrollView addGestureRecognizer:onetap];

[self.scrollView addSubview:imageView];

UITapGestureRecognizer *tapImgViewTwice = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapImgViewHandleTwice:)];

tapImgViewTwice.numberOfTapsRequired = 2;

tapImgViewTwice.numberOfTouchesRequired = 1;

[scrollView addGestureRecognizer:tapImgViewTwice];

//如果双击失败就单击

[onetap requireGestureRecognizerToFail:tapImgViewTwice];

[window addSubview:self.scrollView];

CGFloat imageViewX = 0;

CGFloat imageViewY = (kSCREEN_HEIGHT - image.size.height*kSCREEN_WIDTH/image.size.width) / 2;

CGFloat imageViewW = kSCREEN_WIDTH;

CGFloat imageViewH = image.size.height * kSCREEN_WIDTH/image.size.width;

[UIView animateWithDuration:0.3

animations:^

{

imageView.frame = CGRectMake(imageViewX, imageViewY, imageViewW, imageViewH);

}

completion:^(BOOL finished)

{

}];

}

- (void)hideImage:(UITapGestureRecognizer*)tap

{

UIView *backgroundView = tap.view;

self.userBtnContainer.alpha = 0;

[UIView animateWithDuration:0.3

animations:^

{

self.transImageView.frame = oldframe;

self.scrollView.alpha = 0;

}

completion:^(BOOL finished)

{

[backgroundView removeFromSuperview];

[self.scrollView removeFromSuperview];

[self.userBtnContainer removeFromSuperview];

}];

}

#pragma mark - UIScrollViewDelegate -

-(void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(UIView *)view atScale:(CGFloat)scale

{

self.currentScale = scale;

}

-(UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView{

return self.transImageView;

}

-(void)scrollViewDidZoom:(UIScrollView *)scrollView

{

CGFloat xcenter = scrollView.center.x;

CGFloat ycenter = scrollView.center.y;

xcenter = scrollView.contentSize.width > kSCREEN_WIDTH?scrollView.contentSize.width / 2 : xcenter;

ycenter = scrollView.contentSize.height > kSCREEN_HEIGHT ?scrollView.contentSize.height / 2 : ycenter;

if(_isDoubleTapingForZoom)//是否是双击放大的

{

if (_touchX>0 && _touchY>0)

{

//点击在图片上

CGFloat transformX = _touchX * kMaxZoom;

CGFloat transformY = _touchY * kMaxZoom;

CGFloat contentW = scrollView.contentSize.width;

CGFloat contentH = scrollView.contentSize.height;

if (transformX + kSCREEN_WIDTH *.5>=contentW)

{

//右边太大。

transformX = kSCREEN_WIDTH*(kMaxZoom-1);

}

else

{

if (transformX-kSCREEN_WIDTH *.5 < 0)

{//左边太小

transformX = 0;

}

else

{

transformX = transformX-kSCREEN_WIDTH *0.5;

}

}

//计算Y

//Y的放大比例跟图片的本身有关，需要从新计算内容的高度和屏幕的尺寸关系

int maxCount = contentH /([UIScreen mainScreen].bounds.size.height);

if (maxCount >= 1)

{

//智能移动到中心

if (transformY-contentH *0.5 < 0)

{

//上边太小，智能移动到边界

transformY = 0;

}

else

{

if (transformY +kSCREEN_HEIGHT *.5 > contentH) {

//下边太大，智能移动到边界

transformY = contentH - kSCREEN_HEIGHT;

}

else

{

transformY = transformY - kSCREEN_HEIGHT *.5;

}

}

}

else

{

if (transformY-contentH *0.5 < 0)

{

//上边太小，智能移动到边界

transformY = 0;

}

else

{

//下边太大，智能移动到边界

transformY = ycenter - kSCREEN_HEIGHT*0.5;

}

}

[scrollView setContentOffset:CGPointMake(transformX, transformY)];

}

else

{

//默认放大位置

[scrollView setContentOffset:CGPointMake(xcenter- kSCREEN_WIDTH *.5, ycenter - kSCREEN_HEIGHT*0.5)];

}

}

[self.transImageView setCenter:CGPointMake(xcenter, ycenter)];

_touchY = 0;

_touchX = 0;

}

-(void)tapImgViewHandleTwice:(UIGestureRecognizer *)sender{

_touchX = [sender locationInView:self.transImageView].x;

_touchY = [sender locationInView:self.transImageView].y;

if (_touchY >CGRectGetHeight(self.transImageView.frame))

{

//如果大于最大的就是在图片外面，默认放大

_touchY = 0;

}

if(_isTwiceTaping)//双击

{

return;

}

_isTwiceTaping = YES;

if(_currentScale > 1.0)

{

_currentScale = 1.0;

[_scrollView setZoomScale:1.0 animated:YES];

}

else

{

_isDoubleTapingForZoom = YES;

_currentScale = kMaxZoom;

[_scrollView setZoomScale:kMaxZoom animated:YES];

}

_isDoubleTapingForZoom = NO;

//延时做标记判断，使用户点击3次时的单击效果不生效。

[self performSelector:@selector(twiceTaping) withObject:nil afterDelay:0.65];

}

-(void)twiceTaping{

_isTwiceTaping = NO;

}

//是否添加其他按钮

- (void)addTooBtnView

{

UIView *containerView = [[UIView alloc] initWithFrame:CGRectMake(0, 20, kSCREEN_WIDTH, 80)];

containerView.backgroundColor = [UIColor clearColor];

self.userBtnContainer = containerView;

// [window addSubview:containerView];

/*添加button*/

UIButton *userBtnright = [UIButton buttonWithType:UIButtonTypeSystem];

userBtnright.frame =CGRectMake(kSCREEN_WIDTH - 100, 0, 60, 30);

[userBtnright setTitle:@"正确" forState:UIControlStateNormal];

[userBtnright setBackgroundColor:[UIColor blueColor]];

self.userBtn = userBtnright;

//[containerView addSubview:userBtnright];

/*添加button*/

UIButton *userBtnerror = [UIButton buttonWithType:UIButtonTypeSystem];

userBtnerror.frame =CGRectMake(kSCREEN_WIDTH - 170, 0, 60, 30);

[userBtnerror setTitle:@"错误" forState:UIControlStateNormal];

[userBtnerror setBackgroundColor:[UIColor blueColor]];

self.userBtn = userBtnerror;

//[containerView addSubview:userBtnerror];

}

-(void)dealloc

{

NSLog(@"dealloc");

}

@end