思路

圖片預(yù)覽，優(yōu)先考慮基礎(chǔ)控件UIImageView映凳、UIButton

圖片預(yù)覽中可能需設(shè)置不同的mode胆筒，優(yōu)先考慮UIImageView

typedef NS_ENUM(NSInteger, UIViewContentMode) {
    UIViewContentModeScaleToFill,
    UIViewContentModeScaleAspectFit,      
    UIViewContentModeScaleAspectFill,     
    UIViewContentModeRedraw,             
    UIViewContentModeCenter,              
    UIViewContentModeTop,
    UIViewContentModeBottom,
    UIViewContentModeLeft,
    UIViewContentModeRight,
    UIViewContentModeTopLeft,
    UIViewContentModeTopRight,
    UIViewContentModeBottomLeft,
    UIViewContentModeBottomRight,
}

圖片放大、縮小的思路：1. 手勢(shì)+frame 2.scrollview的zoomScale

很愉快的決定選擇2诈豌，不要問(wèn)為什么仆救，因?yàn)槲覒校苡孟到y(tǒng)提供的矫渔，堅(jiān)決不折騰

上菜

• 設(shè)置頁(yè)面屬性

@property (nonatomic, strong) UIScrollView *mScroll;
@property (nonatomic, strong) UIImageView *imgInfo;

• 界面初始化

self.mScroll = [[UIScrollView alloc] initWithFrame:CGRectZero];
self.mScroll.backgroundColor = [UIColor colorWithHexs:0x3f3f3f];
self.mScroll.maximumZoomScale = 3.0;
self.mScroll.minimumZoomScale = 1;
self.mScroll.delegate = self;
self.mScroll.showsVerticalScrollIndicator = NO;
self.mScroll.showsHorizontalScrollIndicator = NO;
[self.view addSubview:self.mScroll];
[self.mScroll mas_makeConstraints:^(MASConstraintMaker *make) {
    make.edges.equalTo(self.preView);
}];

self.imgInfo = [[UIImageView alloc] initWithFrame:CGRectZero];
self.imgInfo.clipsToBounds = YES;
[self.imgInfo setUserInteractionEnabled:YES];
self.imgInfo.backgroundColor = [UIColor colorWithHexs:0x3f3f3f];
[self.mScroll addSubview:self.imgInfo];
[self.imgInfo mas_makeConstraints:^(MASConstraintMaker *make) {
    make.edges.equalTo(self.mScroll);
    make.width.equalTo(self.mScroll);
}];

其中maximumZoomScale與minimumZoomScale表示可縮放程度

• 順帶加個(gè)雙擊手勢(shì)彤蔽，比如雙擊可放大，再放大庙洼，再縮小

UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapHandlerTwice)];
tap.numberOfTapsRequired = 2;
[self.imgInfo addGestureRecognizer:tap];

• double click直接控制縮放

- (void)tapHandlerTwice {
  if (self.mScroll.zoomScale < 2) {
      [self.mScroll setZoomScale:2];
  } else if (self.mScroll.zoomScale < 3) {
      [self.mScroll setZoomScale:3];
  } else {
      [self.mScroll setZoomScale:1];
  }
}

• UIScrollViewDelegate設(shè)置scrollview的Zooming View

#pragma mark - UIScrollViewDelegate
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView {
    return self.imgInfo;
}

Game Over