how to add watermark on a exist image

Question

I found some code as follows:

 UIGraphicsBeginImageContext(CGSizeMake(320, 480));
// This is where we resize captured image
[(UIImage *)[info objectForKey:UI         


        

Answer 1

Check CGImageCreateWithMask.

Pass the existing image and the watermark image to this function

- (UIImage*) maskImage:(UIImage *)image withMask:(UIImage *)maskImage {

    CGImageRef maskRef = maskImage.CGImage; 

    CGImageRef mask = CGImageMaskCreate(CGImageGetWidth(maskRef),
                                             CGImageGetHeight(maskRef),
                                        CGImageGetBitsPerComponent(maskRef),
                                        CGImageGetBitsPerPixel(maskRef),
                                        CGImageGetBytesPerRow(maskRef),
                                        CGImageGetDataProvider(maskRef), NULL, false);

    CGImageRef masked = CGImageCreateWithMask([image CGImage], mask);

    return [UIImage imageWithCGImage:masked];

}