iOS-WKWebView UIScrollView 全屏截图，网页全屏截图
UiTableView  UIScrollView 全屏截图

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借鉴：https://www.jianshu.com/p/22b0f792ad18

UITableView+SnapImage.h

- (void)ZFJContentCaptureCompletionHandler:(void(^)(UIImage *capturedImage))completionHandler;

- (void)ZFJContentCaptureWithoutOffsetCompletionHandler:(void(^)(UIImage *capturedImage))completionHandler;

UITableView+SnapImage.m

- (void)ZFJContentCaptureCompletionHandler:(void(^)(UIImage *capturedImage))completionHandler{

    CGPoint offset = self.contentOffset;

    UIView *snapShotView = [self snapshotViewAfterScreenUpdates:YES];

    snapShotView.frame = CGRectMake(self.frame.origin.x, self.frame.origin.y, snapShotView.frame.size.width, snapShotView.frame.size.height);

    [self.superview addSubview:snapShotView];

    if(self.frame.size.height < self.contentSize.height){

        self.contentOffset = CGPointMake(0, self.contentSize.height - self.frame.size.height);

    }

    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.3 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{

        self.contentOffset = CGPointZero;

        [self ZFJContentCaptureWithoutOffsetCompletionHandler:^(UIImage *capturedImage) {

            self.contentOffset = offset;

            [snapShotView removeFromSuperview];

            completionHandler(capturedImage);

        }];

    });

}

- (void)ZFJContentCaptureWithoutOffsetCompletionHandler:(void(^)(UIImage *capturedImage))completionHandler{

    UIView *containerView = [[UIView alloc]initWithFrame:self.bounds];

    CGRect bakFrame = self.frame;

    UIView *bakSuperView = self.superview;

    NSInteger bakIndex = [self.superview.subviews indexOfObject:self];

    [self removeFromSuperview];

    [containerView addSubview:self];

    CGSize totalSize = self.contentSize;

    float page = floorf(totalSize.height/containerView.bounds.size.height);

    self.frame = CGRectMake(0, 0, containerView.bounds.size.width, self.contentSize.height);

    UIGraphicsBeginImageContextWithOptions(totalSize, false, [UIScreen mainScreen].scale);

    [self ZFJContentPageDrawTargetView:containerView index:0 maxIndex:(int)page drawCallback:^{

        UIImage *capturedImage = UIGraphicsGetImageFromCurrentImageContext();

        UIGraphicsEndImageContext();

        [self removeFromSuperview];

        [bakSuperView insertSubview:self atIndex:bakIndex];

        self.frame = bakFrame;

        [containerView removeFromSuperview];

        completionHandler(capturedImage);

    }];

}

- (void)ZFJContentPageDrawTargetView:(UIView *)targetView index:(int)index maxIndex:(int)maxIndex drawCallback:(void(^)(void))drawCallback{

    CGRect splitFrame = CGRectMake(0, (float)index * targetView.frame.size.height, targetView.bounds.size.width, targetView.frame.size.height);

    CGRect myFrame = self.frame;

    myFrame.origin.y = - ((float)index * targetView.frame.size.height);

    self.frame = myFrame;

    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.3 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{

        [targetView drawViewHierarchyInRect:splitFrame afterScreenUpdates:YES];

        if(index<maxIndex){

            [self ZFJContentPageDrawTargetView:targetView index:index + 1 maxIndex:maxIndex drawCallback:drawCallback];

        }else{

            drawCallback();

        }

    });

}

WKWebView+SnapImage.m

- (void)ZFJContentCaptureCompletionHandler:(void(^)(UIImage *capturedImage))completionHandler{

    CGPoint offset = self.scrollView.contentOffset;

    UIView *snapShotView = [self snapshotViewAfterScreenUpdates:YES];

    snapShotView.frame = CGRectMake(self.frame.origin.x, self.frame.origin.y, snapShotView.frame.size.width, snapShotView.frame.size.height);

    [self.superview addSubview:snapShotView];

    if(self.frame.size.height < self.scrollView.contentSize.height){

        self.scrollView.contentOffset = CGPointMake(0, self.scrollView.contentSize.height - self.frame.size.height);

    }

    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.3 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{

        self.scrollView.contentOffset = CGPointZero;

        [self ZFJContentCaptureWithoutOffsetCompletionHandler:^(UIImage *capturedImage) {

            self.scrollView.contentOffset = offset;

            [snapShotView removeFromSuperview];

            completionHandler(capturedImage);

        }];

    });

}

- (void)ZFJContentCaptureWithoutOffsetCompletionHandler:(void(^)(UIImage *capturedImage))completionHandler{

    UIView *containerView = [[UIView alloc]initWithFrame:self.bounds];

    CGRect bakFrame = self.frame;

    UIView *bakSuperView = self.superview;

    NSInteger bakIndex = [self.superview.subviews indexOfObject:self];

    [self removeFromSuperview];

    [containerView addSubview:self];

    CGSize totalSize = self.scrollView.contentSize;

    float page = floorf(totalSize.height/containerView.bounds.size.height);

    self.frame = CGRectMake(0, 0, containerView.bounds.size.width, self.scrollView.contentSize.height);

    UIGraphicsBeginImageContextWithOptions(totalSize, false, [UIScreen mainScreen].scale);

    [self ZFJContentPageDrawTargetView:containerView index:0 maxIndex:(int)page drawCallback:^{

        UIImage *capturedImage = UIGraphicsGetImageFromCurrentImageContext();

        UIGraphicsEndImageContext();

        [self removeFromSuperview];

        [bakSuperView insertSubview:self atIndex:bakIndex];

        self.frame = bakFrame;

        [containerView removeFromSuperview];

        completionHandler(capturedImage);

    }];

}

- (void)ZFJContentPageDrawTargetView:(UIView *)targetView index:(int)index maxIndex:(int)maxIndex drawCallback:(void(^)(void))drawCallback{

    CGRect splitFrame = CGRectMake(0, (float)index * targetView.frame.size.height, targetView.bounds.size.width, targetView.frame.size.height);

    CGRect myFrame = self.frame;

    myFrame.origin.y = - ((float)index * targetView.frame.size.height);

    self.frame = myFrame;

    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.3 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{

        [targetView drawViewHierarchyInRect:splitFrame afterScreenUpdates:YES];

        if(index<maxIndex){

            [self ZFJContentPageDrawTargetView:targetView index:index + 1 maxIndex:maxIndex drawCallback:drawCallback];

        }else{

            drawCallback();

        }

    });

}