iOS10-- snapshotViewAfterScreenUpdates 失效

- (UIImage *)imageFromView:(UIView *)snapView {
UIGraphicsBeginImageContext(snapView.frame.size);
CGContextRef context = UIGraphicsGetCurrentContext();
[snapView.layer renderInContext:context];
UIImage *targetImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return targetImage;
}

UIImage *image = [self imageFromView:fromVC.fromVCImageView];
UIImageView *snapView = [[UIImageView alloc] initWithImage:image];
snapView.frame = fromVC.fromVCImageView.frame;
[containerView addSubview:snapView];