 	}
 	
 	
-	// MARK: one-finger double-tap for zoom in
+	// MARK: Gesture 'one-finger double-tap' for zoom in
 	
 	lazy var oneTouchDoubleTapGestureRecognizer: UITapGestureRecognizer = {
 		let instance = UITapGestureRecognizer(target: self, action: #selector(PrecisionSlider.handleOneTouchDoubleTap))

	}
	
	
	// MARK: button for zoom out
	
	lazy var zoomOutButton: UIButton = {
		let instance = UIButton(type: .Custom)

	}
	
	
	// MARK: Pinch gesture for zoom in/out
	
	lazy var pinchGestureRecognizer: UIPinchGestureRecognizer = {
		let instance = UIPinchGestureRecognizer(target: self, action: #selector(PrecisionSlider.handlePinch))
