Hello, currently I am building an UIView in which I'd like to draw over an image. So far I got the drawing part done like so: @objc private func didPanWhiteboard(_ gesture: UIPanGestureRecognizer) {     let location = gesture.location(in: drawCanvasView)           switch gesture.state {       case .began:         path = UIBezierPath()         path.move(to: location)         strokeLayer = CAShapeLayer()         drawCanvasView.layer.addSublayer(strokeLayer)         strokeLayer.strokeColor = toolColor.cgColor         strokeLayer.fillColor = UIColor.clear.cgColor         strokeLayer.lineWidth = toolWidth         strokeLayer.lineJoin = .round         strokeLayer.lineCap = .round         strokeLayer.path = path?.cgPath       case .changed:         path.addLine(to: location)         strokeLayer.path = path.cgPath       case .cancelled, .ended: drawLayers.append(strokeLayer)       default: break     }   } using a pan gesture. Now my problem is that I'd like to have an erase tool for my drawing but I am not sure at all on how to actually erase parts of the stroke.