XKZoomingView.h

#import <UIKit/UIKit.h>

@interface XKZoomingView : UIScrollView
/**
 本地图片
 */
@property (nonatomic, strong) UIImage *mainImage;

/**
 图片显示
 */
@property (nonatomic, strong) UIImageView *mainImageView;
@end

XKZoomingView.m

#import "XKZoomingView.h"
@interface XKZoomingView()<UIScrollViewDelegate>
/**
 当前图片偏移量
 */
@property (nonatomic,assign) CGPoint currPont;
@end
@implementation XKZoomingView

- (instancetype)init{
    self = [super init];
    if (self) {
        [self setup];
    }
    return self;
}
- (instancetype)initWithFrame:(CGRect)frame{
    self = [super initWithFrame:frame];
    if (self) {
        [self setup];
    }
    return self;
}
- (void)setup{
    self.backgroundColor = [[UIColor grayColor]colorWithAlphaComponent:0.2];
    self.delegate = self;
    self.showsHorizontalScrollIndicator = NO;
    self.showsVerticalScrollIndicator = NO;
    self.decelerationRate = UIScrollViewDecelerationRateFast;
    self.maximumZoomScale = 3;
    self.minimumZoomScale = 1;
    self.alwaysBounceHorizontal = NO;
    self.alwaysBounceVertical = NO;
    self.layer.masksToBounds = YES;
    if (@available(iOS 11.0, *)) {
        self.contentInsetAdjustmentBehavior = UIScrollViewContentInsetAdjustmentNever;
    }
    [self addSubview:self.mainImageView];

    _currPont = CGPointZero;

    ///监听屏幕旋转
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(statusBarOrientationChange:) name:UIApplicationDidChangeStatusBarOrientationNotification object:nil];
    ///单击
    UITapGestureRecognizer *tapSingle = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(tapSingleSponse:)];
    //设置手势属性
    tapSingle.numberOfTapsRequired = 1;
    tapSingle.delaysTouchesEnded = NO;
    [self.mainImageView addGestureRecognizer:tapSingle];
    ///双击
    UITapGestureRecognizer *tapDouble = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(tapDoubleSponse:)];
    //设置手势属性
    tapDouble.numberOfTapsRequired = 2;
    [self.mainImageView addGestureRecognizer:tapDouble];
    ///避免手势冲突
    [tapSingle requireGestureRecognizerToFail:tapDouble];
}

#pragma mark - layoutSubviews
- (void)layoutSubviews{
    [super layoutSubviews];
    ///放大或缩小中
    if (self.zooming || self.zoomScale != 1.0 || self.zoomBouncing) {
        return;
    }
    
    ///设置图片尺寸
    if (_mainImage) {
        CGRect imgRect = [self getImageViewFrame];
        self.mainImageView.frame = imgRect;
        ///设置content size
        if (CGRectGetHeight(imgRect) > CGRectGetHeight(self.frame)) {
            [self setContentSize:CGSizeMake(CGRectGetWidth(self.frame), CGRectGetHeight(imgRect))];
        }
        else{
            [self setContentSize:CGSizeMake(CGRectGetWidth(self.frame), CGRectGetHeight(self.frame))];
        }
    }
    
}
- (void)setMainImage:(UIImage *)mainImage{
    _mainImage = mainImage;
    self.mainImageView.image = _mainImage;
    [self setContentOffset:CGPointMake(0, 0)];
    [self setNeedsLayout];
}

/**
 根据图片原始大小，获取图片显示大小
 @return CGRect
 */
- (CGRect)getImageViewFrame{
    if (_mainImage) {
        CGRect imageRect;
        CGFloat scWidth = self.frame.size.width;
        CGFloat scHeight = self.frame.size.height;
        ///width
        if (_mainImage.size.width > scWidth) {
            imageRect.size.width = scWidth;
            CGFloat ratioHW = _mainImage.size.height/_mainImage.size.width;
            imageRect