animate an imageView from a cell to a navbar

gistfile1.txt

func animateSelection(_ collectionView: UICollectionView,
                          didSelectItemAt indexPath: IndexPath) {
        let burgerCell = collectionView.cellForItem(at: indexPath) as! BurgerCollectionViewCell
        let burgerImageView = burgerCell.thumbnailImageView!

        let snapshotImageViewFrame = self.view.convert(burgerImageView.frame,
                                                       from: burgerImageView.superview)

        let snapshotImageView = burgerImageView.snapshotView(afterScreenUpdates: true)!
        self.snapshotView = snapshotImageView

        snapshotImageView.frame = snapshotImageViewFrame
        self.view.addSubview(snapshotImageView)

        let fadeOutAnimation = CABasicAnimation(keyPath: "opacity")
        fadeOutAnimation.toValue = 0.3
        fadeOutAnimation.fillMode = kCAFillModeForwards
        fadeOutAnimation.isRemovedOnCompletion = false

        let resizeAnimation = CABasicAnimation(keyPath: "bounds.size")
        resizeAnimation.toValue = CGSize(width: 40, height: 40)
        resizeAnimation.fillMode = kCAFillModeForwards
        resizeAnimation.isRemovedOnCompletion = false

        let pathAnimation = CAKeyframeAnimation(keyPath: "position")
        pathAnimation.calculationMode = kCAAnimationPaced
        pathAnimation.fillMode = kCAFillModeForwards;
        pathAnimation.isRemovedOnCompletion = false

        let navBarButtonItemView: UIView = self.navigationItem.rightBarButtonItem!.value(forKey: "view") as! UIView

        let navItemFrame = self.view.convert(navBarButtonItemView.frame,
                                             from: navBarButtonItemView.superview)
        let endPoint = CGPoint(x: navItemFrame.midX, y: navItemFrame.midY)

        let curvedPath = CGMutablePath()
        curvedPath.move(to: CGPoint(x: snapshotImageViewFrame.midX, y: snapshotImageViewFrame.midY))

        let controlPoint1 = CGPoint(x: navItemFrame.origin.x + 50, y: navItemFrame.origin.y + 50)
        let controlPoint2 = CGPoint(x: navItemFrame.origin.x + 150, y: navItemFrame.origin.y + 150)

        curvedPath.addCurve(to: endPoint, control1: controlPoint1, control2: controlPoint2)

        pathAnimation.path = curvedPath

        let groupAnimation = CAAnimationGroup()
        groupAnimation.fillMode = kCAFillModeForwards
        groupAnimation.isRemovedOnCompletion = false
        groupAnimation.animations = [fadeOutAnimation, pathAnimation, resizeAnimation]
        groupAnimation.duration = 0.7
        groupAnimation.delegate = self
        groupAnimation.setValue(snapshotImageView, forKey: "imageViewBeingAnimated")
        snapshotImageView.layer.add(groupAnimation, forKey:"savingAnimation")
    }