【Swift5】ImageViewにマスクをかけて画像をくり抜く方法【Xcode10】

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        
        // imgeViewを作成
        let imageView = UIImageView()
        imageView.frame = CGRect(x: 50, y: 50, width: 275, height: 275)
        imageView.image = UIImage(named: "test.jpg")
        self.view.addSubview(imageView)
        
        // マスクレイヤーを用意
        let maskLayer = CAShapeLayer()
        maskLayer.frame = imageView.bounds
        let roundrRectangle = UIBezierPath(roundedRect: CGRect(x: 50,
                                                               y: 50,
                                                               width: 200,
                                                               height: 100),
                                           cornerRadius: 10.0)
        maskLayer.path = roundrRectangle.cgPath

        // マスクを適応
        imageView.layer.mask = maskLayer
    }
}