将整个UIWebView内容保存到摄影机卷；网间网操作系统

到目前为止，我能够从web视图中保存一个图像，即（7683000）；但它会切断当前未显示在屏幕上的任何web视图内容

-(IBAction)capturaScreenButton:(id)sender
{
    UIAlertView *alert;

     CGSize sixzevid=CGSizeMake(768,3000);

    CGSize size = [webView sizeThatFits:CGSizeZero];
    UIGraphicsBeginImageContextWithOptions( size, YES, 0.0);

    UIGraphicsBeginImageContext(sixzevid);
    //UIGraphicsBeginImageContextWithOptions(self.webView.bounds.size, self.webView.opaque, 0.0);
    [self.webView.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

    UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);

    alert = [[UIAlertView alloc] initWithTitle:@"Image captured by Me"
                                       message:@"The image is in your Photo Album..."
                                      delegate:self cancelButtonTitle:@"Ok"
                             otherButtonTitles:nil];
    [alert show];
    [alert release];
    UIGraphicsEndImageContext();

}