1. 全屏截图

+ (UIImage *)snapshotScreen {

    UIWindow *window = [UIApplication sharedApplication].keyWindow;

    UIGraphicsBeginImageContextWithOptions(window.bounds.size, NO, [UIScreen mainScreen].scale);

    [window.layer renderInContext:UIGraphicsGetCurrentContext()];

    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    return image;

}

2. view生成图片

+ (UIImage *)snapshotWithView:(UIView *)view {

    UIGraphicsBeginImageContextWithOptions(view.bounds.size, NO, [UIScreen mainScreen].scale);

    [view.layer renderInContext:UIGraphicsGetCurrentContext()];

    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    return image;

}

3. scrollView生成长图

+ (UIImage *)snapshotWithScrollView:(UIScrollView *)scrollView {

    CGPoint savedContentOffset = scrollView.contentOffset;

    CGRect savedFrame = scrollView.frame;

    scrollView.contentOffset = CGPointZero;

    scrollView.frame = CGRectMake(0, 0, scrollView.contentSize.width, scrollView.contentSize.height);

   UIGraphicsBeginImageContextWithOptions(scrollView.contentSize, NO, [UIScreen mainScreen].scale);

    [scrollView.layer renderInContext: UIGraphicsGetCurrentContext()];

    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    scrollView.contentOffset = savedContentOffset;

    scrollView.frame = savedFrame;

    return image;

}

4. tableView生成长图

+ (UIImage *)snapshotWithTableView:(UITableView *)tableView {

    CGPoint savedContentOffset = tableView.contentOffset;

    CGRect savedFrame = tableView.frame;

    tableView.contentOffset = CGPointZero;

    tableView.frame = CGRectMake(0, 0, tableView.contentSize.width, tableView.contentSize.height);

    UIGraphicsBeginImageContextWithOptions(tableView.contentSize, NO, [UIScreen mainScreen].scale);

    [tableView.layer renderInContext: UIGraphicsGetCurrentContext()];

    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    tableView.contentOffset = savedContentOffset;

    tableView.frame = savedFrame;

    return image;

}

5. WKWebView生成长图

+ (UIImage *)snapshotWithWebView:(WKWebView *)webView {

    CGPoint savedContentOffset = webView.contentOffset;

    CGRect savedFrame = webView.frame;

    webView.contentOffset = CGPointZero;

    webView.frame = CGRectMake(0, 0, webView.contentSize.width, webView.contentSize.height);

    UIGraphicsBeginImageContextWithOptions(webView.contentSize, NO, [UIScreen mainScreen].scale);

    [webView.layer renderInContext: UIGraphicsGetCurrentContext()];

    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    webView.contentOffset = savedContentOffset;

    webView.frame = savedFrame;

    return image;

}

参考来源：https://www.jianshu.com/p/3aa1e3edd1e2