Custom navigation controller push pop transition animation

Example.swift

final class VC1: UIViewController {
    
    private lazy var gr = UITapGestureRecognizer(target: self, action: #selector(self.tap))
    
    override func viewDidLoad() {
        super.viewDidLoad()
        self.view.backgroundColor = .systemPink
        self.view.addGestureRecognizer(self.gr)
        self.navigationController?.delegate = self
    }
    
    @objc private func tap() {
        let vc = UIViewController()
        vc.view.backgroundColor = .systemTeal
        self.navigationController?.pushViewController(vc, animated: true)
    }
    
}

extension VC1: UINavigationControllerDelegate {
    func navigationController(_ navigationController: UINavigationController, animationControllerFor operation: UINavigationController.Operation, from fromVC: UIViewController, to toVC: UIViewController) -> UIViewControllerAnimatedTransitioning? {
        switch operation {
        case .none: break
        case .push: return PushTransitioning()
        case .pop:  return PopTransitioning()
        @unknown default: break
        }
        return nil
    }
}


fileprivate class PushTransitioning: NSObject, UIViewControllerAnimatedTransitioning {
    func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval { 0.3 }
    
    func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
        guard let to = transitionContext.viewController(forKey: .to) else { return }
        
        //  Добавляем вьюху
        let container = transitionContext.containerView
        container.addSubview(to.view)
        
        //  Настраиваем положение
        let frame = transitionContext.finalFrame(for: to)
        to.view.transform = CGAffineTransform(scaleX: 0.9, y: 0.9)
        to.view.frame.origin.x = frame.width
        
        //  Анимируем
        UIView.animateKeyframes(
            withDuration: self.transitionDuration(using: transitionContext),
            delay: 0.0,
            options: []
        ){
            UIView.addKeyframe(
                withRelativeStartTime: 0.0,
                relativeDuration: 0.9
            ) {
                to.view.center.x = frame.width / 2
            }
            UIView.addKeyframe(
                withRelativeStartTime: 0.9,
                relativeDuration: 0.1
            ) {
                to.view.transform = .identity
            }
        } completion: { _ in
            transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
        }
    }
}


fileprivate class PopTransitioning: NSObject, UIViewControllerAnimatedTransitioning {
    func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval { 0.3 }
    
    func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
        guard
            let to   = transitionContext.viewController(forKey: .to),
            let from = transitionContext.viewController(forKey: .from)
        else { return }
        
        //  Добавляем вьюху
        let container = transitionContext.containerView
        container.insertSubview(to.view, belowSubview: from.view)
        
        //  Положение
        let width = transitionContext.initialFrame(for: from).width
        
        //  Анимируем
        UIView.animateKeyframes(
            withDuration: self.transitionDuration(using: transitionContext),
            delay: 0.0,
            options: [],
            animations: {
                UIView.addKeyframe(
                    withRelativeStartTime: 0.0,
                    relativeDuration: 0.1,
                    animations: {
                        from.view.transform = CGAffineTransform(scaleX: 0.9, y: 0.9)
                    }
                )
                UIView.addKeyframe(
                    withRelativeStartTime: 0.1,
                    relativeDuration: 0.9,
                    animations: {
                        from.view.frame.origin.x = width
                    }
                )
            },
            completion: { _ in
                transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
            }
        )
    }
}