 		state = .tracking
 	}
 	
-	fileprivate func adjustMaskLayer(basedOn panRecognizer: PessimisticPanGestureRecognizer) {
+	private func adjustMaskLayer(basedOn panRecognizer: PessimisticPanGestureRecognizer) {
 		adjustMaskLayerPosition(basedOn: panRecognizer)
 		adjustMaskLayerPath(basedOn: panRecognizer)
 	}
 	
-	fileprivate func adjustMaskLayerPosition(basedOn panRecognizer: PessimisticPanGestureRecognizer) {
+	private func adjustMaskLayerPosition(basedOn panRecognizer: PessimisticPanGestureRecognizer) {
 		// We need to disable implicit animations since we don't want to
 		// animate the position change of the mask layer.
 		CATransaction.begin()

		CATransaction.commit()
	}
	
	fileprivate func adjustMaskLayerPath(basedOn panRecognizer: PessimisticPanGestureRecognizer) {
		let maskingPath = UIBezierPath()
		
		// Top-left corner...

	/// As the transition progresses, less and less of the snapshot view
	/// will be visible, revealing more of the real view which is styled
	/// with the new style.
	private var previousStyleViewSnapshot: UIView?
	
	/// During the interactive transition, this property contains the layer
	/// used to mask the contents of `previousStyleViewSnapshot`.
	/// When the user pans, the position and path of `snapshotMaskLayer` is
	/// adjusted to reflect the current translation of the pan recognizer.
	private var snapshotMaskLayer: CAShapeLayer?
	
	private func beginInteractiveStyleTransition(withPanRecognizer panRecognizer: PessimisticPanGestureRecognizer) {
		// We snapshot the targetView before applying the new style, and make sure
		// it's positioned on top of all the other content.
		previousStyleViewSnapshot = targetView.snapshotView(afterScreenUpdates: false)
