how to add watermark on a exist image
<p>as topic, or whether has exist open source library that can be use for such function ?  adjust size, rotate , or etc.</p>

<p>thanks for help in advanced </p>

<p>again, I found some code as follows:</p>

<pre><code> UIGraphicsBeginImageContext(CGSizeMake(320, 480));
// This is where we resize captured image
[(UIImage *)[info objectForKey:UIImagePickerControllerOriginalImage] drawInRect:CGRectMake(0, 0, 320, 480)];
// And add the watermark on top of it
[[UIImage imageNamed:@"Watermark.png"] drawAtPoint:CGPointMake(0, 0) blendMode:kCGBlendModeNormal alpha:WATERMARK_ALPHA];
// Save the results directly to the image view property
imageView.image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
</code></pre>

<p>but I am not sure whether this best way.</p>
