iOS - how to implement crop image like default photo album?

Question

The default crop function in iPhone photo album

Does any one know how to i

Answer 1

func cropImageZero(_ completionHandler: (_ img: UIImage)->()){
        let image = UIImage(named: "name")
        let rect = CGRect(x: 0, y: y, width: width, height: height)
        let cgImage = image?.cgImage!.cropping(to: rect)
        let imageNew = UIImage(cgImage: cgImage!)
        completionHandler(imageNew)
}

image cropping, in Swift 4,

Bonnie's answer is useful