wodeshebao-iOS/我的社保/Public/Album/JXHZoomImageView.m

//
//  JXHZoomImageView.m
//  我的社保
//
//  Created by shanp on 2020/9/17.
//

#import "JXHZoomImageView.h"
#import "JXHMacro.h"
#import "JXHSystemShortcut.h"
#import "JXHLayout.h"
#import <JXHViewMeasure.h>
#import <UIImageView+WebCache.h>

@interface JXHZoomImageView ()<UIScrollViewDelegate> {
        
    CGFloat _maxZoom;
    
    CGFloat _verticalContentInset;
}

@end

@implementation JXHZoomImageView

- (instancetype)initWithTarget:(id)target action:(SEL)action {
    self = [super init];
    if (!self) return nil;
    [self initViewWithTarget:target action:action];
    [self createImageView];
    return self;
}

- (void)initViewWithTarget:(id)target action:(SEL)action {
    self.minimumZoomScale = 1.f;
    self.maximumZoomScale = _maxZoom = 2.f;
    self.showsHorizontalScrollIndicator = false;
    self.showsVerticalScrollIndicator = false;
    self.multipleTouchEnabled = true;
    self.delegate = self;
    
    UITapGestureRecognizer *doubleTap = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(doubleTap:)];
    [doubleTap setNumberOfTapsRequired:2];
    [self addGestureRecognizer:doubleTap];
    
    UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc]initWithTarget:target action:action];
    [singleTap setNumberOfTapsRequired:1];
    [self addGestureRecognizer:singleTap];
    
    //只有当没有检测到doubleTap 或者 检测doubleTap失败，sigleTap才有效
    [singleTap requireGestureRecognizerToFail:doubleTap];
}

- (void)createImageView {
    _jxh_imageView = UIImageView.new;
    _jxh_imageView.frame = (CGRect){CGPointZero, (CGSize){jxh_viewWidth(self), jxh_viewHeight(self)}};
    _jxh_imageView.contentMode = UIViewContentModeScaleAspectFit;
    [self addSubview:_jxh_imageView];
}

#pragma mark - Action
-(void)doubleTap:(UIGestureRecognizer *)gestureRecognizer{
    NSInteger newScale = [self zoomScale] == 1 ? _maxZoom : 1;
    [self setZoomScale:newScale animated:true];
}

- (void)setImageUrl:(NSURL *)url {
    @weakify(self)
    [_jxh_imageView sd_setImageWithURL:url completed:^(UIImage * _Nullable image, NSError * _Nullable error, SDImageCacheType cacheType, NSURL * _Nullable imageURL) {
        @strongify(self)
        [self setImage:image];
    }];
}

- (void)setImage:(nullable UIImage *)image {
    if (jxh_viewWidth(self) == 0.f) {
        [self.superview layoutSubviews];
    }
    [self setZoomScale:1 animated:false];
    CGSize size;
    if (!image) {
        self.maximumZoomScale = _maxZoom = 2.f;
        _verticalContentInset = 0.f;
        size = (CGSize){jxh_viewWidth(self), jxh_viewHeight(self)};
    } else if (image.size.width / image.size.height >= jxh_viewWidth(self) / jxh_viewHeight(self)) {
        CGFloat height = image.size.height / image.size.width * jxh_viewWidth(self);
        _maxZoom = jxh_viewHeight(self) / height;
        if (_maxZoom < 2) {
            self.maximumZoomScale = _maxZoom = 2.0;
        } else {
            self.maximumZoomScale = _maxZoom * 2.0;
        }
        _verticalContentInset = (jxh_viewHeight(self) - height) / 2;
        size = (CGSize){jxh_viewWidth(self), jxh_viewHeight(self)};
    } else {
        self.maximumZoomScale = _maxZoom = 2.f;
        _verticalContentInset = 0.f;
        size = (CGSize){jxh_viewWidth(self), image.size.height / image.size.width * jxh_viewWidth(self)};
    }
    _jxh_imageView.frame = (CGRect){CGPointZero, size};
    [self setContentSize:_jxh_imageView.frame.size];
    [self setContentInset:UIEdgeInsetsZero];
    _jxh_imageView.image = image;
}

#pragma mark - Delegate
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView {
    return _jxh_imageView;
}

- (void)scrollViewWillBeginZooming:(UIScrollView *)scrollView withView:(UIView *)view {
}

- (void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(UIView *)view atScale:(CGFloat)scale {
    if (scale > 1) {
        CGFloat height = _jxh_imageView.image.size.height / _jxh_imageView.image.size.width * jxh_viewWidth(_jxh_imageView);
        CGFloat y = 0.f;
        if (height < jxh_screenHeight()) {
            y = (jxh_screenHeight() - height) / 2;
        }
        _jxh_imageView.frame = (CGRect){(CGPoint){0, y}, _jxh_imageView.frame.size};
        scrollView.contentInset = UIEdgeInsetsMake(- _verticalContentInset * scale, 0, - _verticalContentInset * scale, 0);
    } else {
        _jxh_imageView.frame = (CGRect){CGPointZero, _jxh_imageView.frame.size};
        [scrollView setContentInset:UIEdgeInsetsZero];
    }
    
}

- (void)scrollViewDidZoom:(UIScrollView *)scrollView {
    CGFloat height = _jxh_imageView.image.size.height / _jxh_imageView.image.size.width * jxh_viewWidth(_jxh_imageView);
    CGFloat y = 0.f;
    if (height < jxh_screenHeight()) {
        y = (jxh_screenHeight() - height) / 2;
    }
    _jxh_imageView.frame = (CGRect){(CGPoint){0, y}, _jxh_imageView.frame.size};
    scrollView.contentInset = UIEdgeInsetsMake(- _verticalContentInset * scrollView.zoomScale, 0, - _verticalContentInset * scrollView.zoomScale, 0);
}

//- (CGRect)zoomRectForScale:(NSInteger)scale withCenter:(CGPoint)center {
//
//    CGRect zoomRect;
//
//    zoomRect.size.height = [self frame].size.height / scale;
//    zoomRect.size.width  = [self frame].size.width  / scale;
//
//    zoomRect.origin.x    = center.x - (zoomRect.size.width  / 2.0) - (jxh_screenWidth() - _imageView.frame.size.width) / 2;
//    zoomRect.origin.y    = center.y - (zoomRect.size.height / 2.0) - (jxh_screenHeight() - _imageView.frame.size.height) / 2;
//    return zoomRect;
//}

@end