webView全部内容截取成图片

    UIGraphicsBeginImageContext(webView.bounds.size); 
[webView.layer renderInContext:UIGraphicsGetCurrentContext()];
    
    _currentImage = [self getImageFromView:webView];
    UIGraphicsEndImageContext();
    UIImageWriteToSavedPhotosAlbum(_currentImage, self, @selector(imageSavedToPhotosAlbum:didFinishSavingWithError:contextInfo:), nil); 
- (UIImage *)getImageFromView:(UIView *)view
{
    UIImage *pngImg;   
    UIGraphicsBeginImageContextWithOptions(CGSizeMake(viewSize.width, viewSize.height),YES,[UIScreen mainScreen].scale);
    // 设置view成全部展开效果
    [view setFrame: CGRectMake(0, 0, view.size.width, view.size.height)];
    CGContextRef context = UIGraphicsGetCurrentContext();
    [view.layer renderInContext:context];
    pngImg =  UIGraphicsGetImageFromCurrentImageContext() ;
    UIGraphicsEndImageContext();
    return pngImg;
}
- (void)imageSavedToPhotosAlbum:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo
{
    NSString *message = @"text";
    if (!error) {
        message = @"成功保存到相册";
        
    }else
    {
        message = [error description];
    }
} 

注意:scale(缩放因子)大小影响截图内容清晰度，尽量写[UIScreen mainScreen].scale