- (UIImage *)maskFrame:(UIImage *)firstImage withFrame:(UIImage *)maskImage
{	
	CGImageRef image = firstImage.CGImage;
	CGImageRef maskImageRef = maskImage.CGImage;
	CGRect bounds = CGRectMake(0, 0, CGImageGetWidth(image), CGImageGetHeight(image)); // clip 2 pixels hor and vert
	UIGraphicsBeginImageContext(bounds.size);
	
	// rotate context
	CGContextTranslateCTM(UIGraphicsGetCurrentContext(), 0, bounds.size.height);
	CGContextScaleCTM(UIGraphicsGetCurrentContext(), 1.0, -1.0);
	
	// draw first image
	CGContextDrawImage(UIGraphicsGetCurrentContext(), CGRectMake(0, 0, CGImageGetWidth(image), CGImageGetHeight(image)), image);
	
	// draw mask
	//	CGContextDrawImage(UIGraphicsGetCurrentContext(), CGRectMake(0, 0, CGImageGetWidth(maskedImage), CGImageGetHeight(maskedImage)), maskedImage);
	
	const float myMaskingColors[6] = {0, 0, 0, 0, 0, 0};
	CGImageRef myColorMaskedImage = CGImageCreateWithMaskingColors (maskImageRef, myMaskingColors);
	CGContextDrawImage (UIGraphicsGetCurrentContext(), CGRectMake(0, 0, CGImageGetWidth(myColorMaskedImage), CGImageGetHeight(myColorMaskedImage)), myColorMaskedImage);	
	//CGContextDrawImage(UIGraphicsGetCurrentContext(), CGRectMake(0, 0, CGImageGetWidth(maskImageRef), CGImageGetHeight(maskImageRef)), maskImageRef);
	
	// rotate context back
	CGContextTranslateCTM(UIGraphicsGetCurrentContext(), 0, CGImageGetHeight(image));
	CGContextScaleCTM(UIGraphicsGetCurrentContext(), 1.0, -1.0);
	
	
	UIImage *imageCopy = UIGraphicsGetImageFromCurrentImageContext();
	UIGraphicsEndImageContext();
	
	return imageCopy;
}