截取tableview

-(void)savePhoto
{  [self.tableView scrollToRowAtIndexPath:[NSIndexPath indexPathForRow:self.albumDetailDataModel.groups.count - 1 inSection:0] atScrollPosition:UITableViewScrollPositionBottom animated:YES];

    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(3 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
            UIImage * image = [self getCapture];
        ALAssetsLibrary * library = [ALAssetsLibrary new];
        NSData * data = UIImageJPEGRepresentation(image, 1.0);
        [library writeImageDataToSavedPhotosAlbum:data metadata:nil completionBlock:nil];
    });
   
}

- (UIImage*)getCapture{
    
    UIImage* viewImage = nil;
    UITableView *scrollView = self.tableView;
    UIGraphicsBeginImageContextWithOptions(scrollView.contentSize, scrollView.opaque, 0.0);
    {
        CGPoint savedContentOffset = scrollView.contentOffset;
        CGRect savedFrame = scrollView.frame;
        
        scrollView.contentOffset = CGPointZero;
        scrollView.frame = CGRectMake(0, 0, scrollView.contentSize.width, scrollView.contentSize.height);
        
        [scrollView.layer renderInContext: UIGraphicsGetCurrentContext()];
        viewImage = UIGraphicsGetImageFromCurrentImageContext();
        
        scrollView.contentOffset = savedContentOffset;
        scrollView.frame = savedFrame;
    }
    UIGraphicsEndImageContext();
    
    return viewImage;
}