Extension of UIImage the helps cropping an image with an example of how to use the result of UIImagePickerController. Credit: original Objective-C code: http://blog.cmgresearch.com/2012/07/14/Cropping-the-results-from-UIImagePickerController.html

UIImage+crop.swift

/* 
  Usage example:

    // MARK - UIImagePickerControllerDelegate
    
    func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : AnyObject]) {
        if let pickedImage = info[UIImagePickerControllerOriginalImage] as? UIImage {
            let cropRect = info[UIImagePickerControllerCropRect]?.CGRectValue
            let croppedImage = pickedImage.crop(cropRect)
            self.anImage.contentMode = .ScaleAspectFit
            self.anImage.image = croppedImage
        }
        
        dismissViewControllerAnimated(true, completion: nil)
    }
    
  */

extension UIImage {
    func crop(rect: CGRect?) -> UIImage {
        guard let rect = rect else {
            return self
        }
        
        // create a graphics context of the correct size
        UIGraphicsBeginImageContext(rect.size)
        let context = UIGraphicsGetCurrentContext()
        
        var cropRect: CGRect?
        
        // correct for image orientation
        if imageOrientation == .Up {
            CGContextTranslateCTM(context, 0, size.height)
            CGContextScaleCTM(context, 1, -1)
            cropRect = CGRectMake(rect.origin.x,
                -rect.origin.y,
                rect.size.width,
                rect.size.height);
        }
        else if imageOrientation == .Right {
            CGContextScaleCTM(context, 1.0, -1.0)
            CGContextRotateCTM(context, CGFloat(-M_PI / 2.0))
            cropRect = CGRectMake(rect.origin.y,
                rect.origin.x,
                rect.size.height,
                rect.size.width)
        }
        else if imageOrientation == .Down {
            CGContextTranslateCTM(context, size.width, 0);
            CGContextScaleCTM(context, -1, 1);
            cropRect = CGRectMake(-rect.origin.x,
                rect.origin.y,
                rect.size.width,
                rect.size.height)
        }
        
        // draw the image in the correct place
        CGContextTranslateCTM(context, -cropRect!.origin.x, -cropRect!.origin.y)
        CGContextDrawImage(context,
            CGRectMake(0,0, size.width, size.height),
            CGImage)
        // and pull out the cropped image
        let croppedImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        
        return croppedImage
    }
}