CircularTransition

@IBOutlet weak var menuButton: UIButton!

@IBOutlet weak var clubButton: UIButton!

@IBOutlet weak var announcemnetsButton: UIButton!

@IBOutlet weak var eventButton: UIButton!

let transition  = CircularTransition()

override func viewDidLoad() {
    super.viewDidLoad()

    menuButton.layer.cornerRadius = menuButton.frame.size.width / 2
   clubButton.layer.cornerRadius = menuButton.frame.size.width / 2
    announcemnetsButton.layer.cornerRadius = menuButton.frame.size.width / 2
    eventButton.layer.cornerRadius = menuButton.frame.size.width / 2
    // Do any additional setup after loading the view.

}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    let secondVC = segue.destination as! NewViewController
    secondVC.transitioningDelegate = self
    secondVC.modalPresentationStyle = .custom
    let thirdVC = segue.destination as! ClubsViewController
    thirdVC.transitioningDelegate = self
    thirdVC.modalPresentationStyle = .custom
    let fourthVC = segue.destination as! AnnouncementsViewController
    fourthVC.transitioningDelegate = self
    fourthVC.modalPresentationStyle = .custom
    let fifthVC = segue.destination as! EventsViewController
    fifthVC.transitioningDelegate = self
    fifthVC.modalPresentationStyle = .custom
}

    class CircularTransition: NSObject {

    var circle = UIView()

    var startingPoint = CGPoint.zero {
        didSet {
            circle.center = startingPoint
        }
    }

    var circleColor = UIColor.whiteColor()

    var duration = 0.3

    enum CircularTransitionMode:Int {
        case present, dismiss, pop
    }

    var transitionMode:CircularTransitionMode = .present

}

extension CircularTransition:UIViewControllerAnimatedTransitioning {

    func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> NSTimeInterval {
        return duration
    }

    func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
        let containerView = transitionContext.containerView

        if transitionMode == .present {
            if let presentedView = transitionContext.viewForKey(UITransitionContextToViewControllerKey) {
                let viewCenter = presentedView.center
                let viewSize = presentedView.frame.size

                circle = UIView()

                circle.frame = frameForCircle(withViewCenter: viewCenter, size: viewSize, startPoint: startingPoint)

                circle.layer.cornerRadius = circle.frame.size.height / 2
                circle.center = startingPoint
                circle.backgroundColor = circleColor
                circle.transform = CGAffineTransformMakeScale(0.001, 0.001)
                containerView()!.addSubview(circle)


                presentedView.center = startingPoint
                presentedView.transform = CGAffineTransformMakeScale(0.001, 0.001)
                presentedView.alpha = 0
                containerView()!.addSubview(presentedView)

                UIView.animateWithDuration(duration, animations: {
                    self.circle.transform = CGAffineTransformIdentity
                    presentedView.transform = CGAffineTransformIdentity
                    presentedView.alpha = 1
                    presentedView.center = viewCenter

                    }, completion: { (success:Bool) in
                        transitionContext.completeTransition(success)
                })
            }

        } else {
            let transitionModeKey = (transitionMode == .pop) ? UITransitionContextToViewKey : UITransitionContextFromViewKey

            if let returningView = transitionContext.viewForKey(transitionModeKey) {
                let viewCenter = returningView.center
                let viewSize = returningView.frame.size


                circle.frame = frameForCircle(withViewCenter: viewCenter, size: viewSize, startPoint: startingPoint)

                circle.layer.cornerRadius = circle.frame.size.height / 2
                circle.center = startingPoint

                UIView.animateWithDuration(duration, animations: {
                    self.circle.transform = CGAffineTransformMakeScale(0.001, 0.001)
                    returningView.transform = CGAffineTransformMakeScale(0.001, 0.001)
                    returningView.center = self.startingPoint
                    returningView.alpha = 0

                    if self.transitionMode == .pop {
                        containerView()!.insertSubview(returningView, belowSubview: returningView)
                        containerView()!.insertSubview(self.circle, belowSubview: returningView)
                    }


                    }, completion: { (success:Bool) in
                        returningView.center = viewCenter
                        returningView.removeFromSuperview()

                        self.circle.removeFromSuperview()

                        transitionContext.completeTransition(success)

                })

            }


        }

    }

    func frameForCircle (withViewCenter viewCenter:CGPoint, size viewSize:CGSize, startPoint:CGPoint) -> CGRect {
        let xLength = fmax(startPoint.x, viewSize.width - startPoint.x)
        let yLength = fmax(startPoint.y, viewSize.height - startPoint.y)

        let offestVector = sqrt(xLength * xLength + yLength * yLength) * 2
        let size = CGSize(width: offestVector, height: offestVector)

        return CGRect(origin: CGPoint.zero, size: size)

    }

}