override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)

        transitionUI(toState: .final, animated: true)
    }

private func transitionUI(toState state: UIState, animated: Bool, completion: ((Bool) -> Void)? = nil) {
        let layoutGuide: UILayoutGuide = {
            switch state {
            case .initial: return initialStateContentLayoutGuide
            case .final: return finalStateContentLayoutGuide
            }
        }()

        let hideControls = state == .initial
        let setControlsHiddenBlock = {
            let alpha: CGFloat = hideControls ? 0 : 1
            self.footerView.alpha = alpha
            self.cropView.setState(state == .initial ? .initial : .normal, animated: false)
            self.bottomBar.setControls(hidden: hideControls)
        }

        let animationDuration: TimeInterval = 0.15

        let imageCornerRadius: CGFloat = state == .initial ? ImageEditorView.defaultCornerRadius : 0
        if animated {
            let animation = CABasicAnimation(keyPath: #keyPath(CALayer.cornerRadius))
            animation.fromValue = imageView.layer.cornerRadius
            animation.toValue = imageCornerRadius
            animation.duration = animationDuration
            imageView.layer.add(animation, forKey: "cornerRadius")
        }
        imageView.layer.cornerRadius = imageCornerRadius

        if animated {
            UIView.animate(withDuration: animationDuration,
                           animations: {
                setControlsHiddenBlock()
                self.constrainContent(to: layoutGuide)
                self.updateImageViewTransform()
                // Animate layout changes made within bottomBar.setControls(hidden:).
                self.view.setNeedsDisplay()
                self.view.layoutIfNeeded()
            },
                           completion: completion)
        } else {
            setControlsHiddenBlock()
            constrainContent(to: layoutGuide)
            updateImageViewTransform()
            completion?(true)
        }
    }