class ViewController: UIViewController {

  override func viewDidLoad() {
    super.viewDidLoad()
    modalPresentationStyle = .overFullScreen
    view.addGestureRecognizer(UIPanGestureRecognizer(target: self, action: #selector(panGestureRecognizerHandler)))
  }

  @objc func panGestureRecognizerHandler(_ gesture: UIPanGestureRecognizer) {
    let translation = gesture.translation(in: view)

    view.frame.origin = translation

    if gesture.state == .ended {
      let velocity = gesture.velocity(in: view)

      if velocity.y >= 1500 {
        self.dismiss(animated: true)
      } else {
        UIView.animate(withDuration: 0.3, animations: {
          self.view.frame.origin = CGPoint.zero
        })
      }
    }
  }
}