A basic transition that properly pushes off transparent views

MPNavigationAnimatedTransitiion.swift

import UIKit

class MPNavigationAnimatedTransitiion: NSObject, UIViewControllerAnimatedTransitioning {

    let operation: UINavigationControllerOperation

    init(operation: UINavigationControllerOperation) {
        self.operation = operation
    }

    @objc func transitionDuration(transitionContext: UIViewControllerContextTransitioning?) -> NSTimeInterval {
        return Constants.UI.Animation.controllerPushPop
    }

    @objc func animateTransition(transitionContext: UIViewControllerContextTransitioning) {
        let container = transitionContext.containerView()

        guard let fromVC = transitionContext.viewControllerForKey(UITransitionContextFromViewControllerKey), toVC = transitionContext.viewControllerForKey(UITransitionContextToViewControllerKey) else {
            return
        }

        let fromView = fromVC.view
        let toView = toVC.view

        let containerWidth = container.frame.width

        var toInitialFrame = container.frame
        var fromDestinationFrame = fromView.frame

        if operation == .Push {
            toInitialFrame.origin.x = containerWidth
            toView.frame = toInitialFrame
            fromDestinationFrame.origin.x = -containerWidth
        } else if operation == .Pop {
            toInitialFrame.origin.x = -containerWidth
            toView.frame = toInitialFrame
            fromDestinationFrame.origin.x = containerWidth
        }

        toView.userInteractionEnabled = false
        if !container.subviews.contains(toView) {
            container.addSubview(toView)
        }

        UIView.animateWithDuration(Constants.UI.Animation.controllerPushPop, delay: 0.0, usingSpringWithDamping: 1000, initialSpringVelocity: 1, options: [], animations: {
            toView.frame = container.frame
            fromView.frame = fromDestinationFrame
            }) { (finished) in
                toView.frame = container.frame
                toView.userInteractionEnabled = true
                fromView.removeFromSuperview()
                transitionContext.completeTransition(true)
        }
    }
}

MyViewController.swift

class MyViewController: UIViewController, UINavigationControllerDelegate {
    func navigationController(navigationController: UINavigationController, animationControllerForOperation operation: UINavigationControllerOperation, fromViewController fromVC: UIViewController, toViewController toVC: UIViewController) -> UIViewControllerAnimatedTransitioning? {
        return MPNavigationAnimatedTransitiion(operation: operation)
    }
}