Make a perfect-circle cutout of any image in Objective-C

CutoutMask.m

// This function will create perfect-circle cutout of any image you supply.
// So if you have a solid black image, the resulting PNG will be a "cutout-out" (transparent)
// circle with a border of solid black. It will return NSData (for use with Parse's PFFile), 
// but can be easily modified to return the resulting UIImage (*img)
// 
// @param {UIImage} The image you want to "cutout"
// @param {CGSize} The size (width and height) you want the resulting image to be
// return {NSData} the PNGrepresentation of the resulting UIImage
-(NSData *)createCircleCutOutofImage:(UIImage *)image withSize:(CGSize)size {
    
    UIGraphicsBeginImageContextWithOptions(size, NO, 0.0);
    CGContextRef context = UIGraphicsGetCurrentContext();
    
    [image drawInRect:CGRectMake(0, 0, size.width, size.height)];
    
    CGRect clippingEllipseRect = CGRectMake(0, 0, size.width, size.width);
    CGContextAddEllipseInRect(context, clippingEllipseRect);
    CGContextClip(context);
    CGContextClearRect(context, clippingEllipseRect);
    
    UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
    
    UIGraphicsEndImageContext();
    
    // return NSData
    return UIImagePNGRepresentation(img);
    
}