iOS example of using UIViewControllerTransitioningDelegate to create a slide to reveal effect.

SlideRevealTransitioner.swift

// A common effect when you press a hamburger button.

public class SlideRevealTransitioner: NSObject {
    private let percentage: CGFloat
    
    public init(percentage: CGFloat) {
        self.percentage = percentage
    }
    
    private var presenting = true
}


extension SlideRevealTransitioner: UIViewControllerTransitioningDelegate {
    
    public func animationControllerForPresentedController(presented: UIViewController,
                                    presentingController presenting: UIViewController,
                                            sourceController source: UIViewController) -> UIViewControllerAnimatedTransitioning? {
        self.presenting = true
        return self
    }
    
    public func animationControllerForDismissedController(dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning? {
        self.presenting = false
        return self
    }
}


extension SlideRevealTransitioner: UIViewControllerAnimatedTransitioning {
    
    public func transitionDuration(transitionContext: UIViewControllerContextTransitioning?) -> NSTimeInterval {
        return 0.3
    }
    
    public func animateTransition(transitionContext: UIViewControllerContextTransitioning) {
        guard let fromVC = transitionContext.viewControllerForKey(UITransitionContextFromViewControllerKey),
              let toVC = transitionContext.viewControllerForKey(UITransitionContextToViewControllerKey) else {
                return
        }
        if presenting {
            show(toVC, fromVC: fromVC, context: transitionContext)
        } else {
            hide(toVC, fromVC: fromVC, context: transitionContext)
        }
    }
}


private extension SlideRevealTransitioner {
    
    func show(toVC: UIViewController, fromVC: UIViewController, context: UIViewControllerContextTransitioning) {
        guard let containerView = context.containerView() else {
            return
        }
        
        let finalFrame = CGRectOffset(fromVC.view.frame, fromVC.view.bounds.width * percentage, 0)
        toVC.view.frame = fromVC.view.frame
        containerView.addSubview(toVC.view)
        
        let originalSuperview = fromVC.view.superview
        containerView.addSubview(fromVC.view)
        toVC.beginAppearanceTransition(true, animated: true)
        
        UIView.animateWithDuration(transitionDuration(context), animations: { 
                fromVC.view.frame = finalFrame
            }) { finished in
                context.completeTransition(true)
                originalSuperview?.addSubview(fromVC.view)
                containerView.superview?.bringSubviewToFront(containerView)
                toVC.endAppearanceTransition()
        }
    }
    
    func hide(toVC: UIViewController, fromVC: UIViewController, context: UIViewControllerContextTransitioning) {
        let containerView = context.containerView()
        let finalFrame = context.finalFrameForViewController(toVC)
        let originalSuperview = toVC.view.superview
        containerView?.addSubview(toVC.view)
        toVC.beginAppearanceTransition(true, animated: true)
        
        UIView.animateWithDuration(transitionDuration(context), animations: { 
                toVC.view.frame = finalFrame
            }) { finished in
                originalSuperview?.addSubview(toVC.view)
                fromVC.view.removeFromSuperview()
                context.completeTransition(true)
                toVC.endAppearanceTransition()
        }
    }
}