如何通过缩放呈现UIViewController？

func presentViewControllerWithScaleAnimation(viewControllerToPresent: UIViewController) {
    viewControllerToPresent.modalPresentationStyle = .custom
    self.present(viewControllerToPresent, animated: true, completion: nil)
}

class YourViewController: UIViewController, UIViewControllerTransitioningDelegate {
    // Your view controller code
}

func animationController(forPresented presented: UIViewController, presenting: UIViewController, source: UIViewController) -> UIViewControllerAnimatedTransitioning? {
    return ScaleAnimationController(presenting: true)
}

class ScaleAnimationController: NSObject, UIViewControllerAnimatedTransitioning {
    let presenting: Bool

    init(presenting: Bool) {
        self.presenting = presenting
    }

    func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
        return 0.3
    }

    func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
        let key = presenting ? UITransitionContextViewControllerKey.to : UITransitionContextViewControllerKey.from
        let controller = transitionContext.viewController(forKey: key)!

        if presenting {
            controller.view.transform = CGAffineTransform(scaleX: 0.001, y: 0.001)
            transitionContext.containerView.addSubview(controller.view)
        }

        let duration = transitionDuration(using: transitionContext)
        UIView.animate(withDuration: duration, delay: 0.0, usingSpringWithDamping: 0.6, initialSpringVelocity: 0.0, options: [], animations: {
            controller.view.transform = self.presenting ? CGAffineTransform(scaleX: 1.0, y: 1.0) : CGAffineTransform(scaleX: 0.001, y: 0.001)
        }) { _ in
            transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
        }
    }
}

self.transitioningDelegate = self