我需要使用PencilKit在图像上绘制。我面临的问题是我无法更改PencilKit工具选择器工具（例如，钢笔到铅笔）。我只能在PKInkTool中使用钢笔模式
发布我的代码如下

class ViewController: UIViewController, PKToolPickerObserver {
    
    
    private var  canvasView :PKCanvasView!
    @IBOutlet weak var imgView: UIImageView!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
    }
    
    override func viewDidAppear(_ animated: Bool) {
       setup()
    }
    
    func setup() {
        
        
        let navigationItem = navigationController?.navigationBar.topItem
        
        let pencilButton = UIButton(frame: CGRect(x: 0, y: 0, width: 50, height: 50))
        pencilButton.addTarget(self, action: #selector(showPKToolKit), for: .touchUpInside)
        pencilButton.setImage(UIImage(systemName: "pencil.tip"), for: .normal)
        pencilButton.tintColor = .tintColor
        
        navigationItem?.rightBarButtonItem = UIBarButtonItem(customView: pencilButton)
        
        let fileManager = FileManager.default
        guard let documentsURL = fileManager.urls(for: .documentDirectory, in: .userDomainMask).first else { return  }

        let urls: [URL]
        do {
          urls = try fileManager.contentsOfDirectory(at: documentsURL, includingPropertiesForKeys: nil)
        } catch {
          fatalError("Couldn't load files from documents directory")
        }

        do{
            let data = try Data(contentsOf: urls[0])
            print(data)
            imgView.image = UIImage(data:data)
        }catch{
            
            print("failed to load image")
        }

        canvasView = PKCanvasView.init(frame: self.imgView.frame)
        self.canvasView.isOpaque = false
        self.view.addSubview(self.canvasView)
        
     
        
    }
    
    @objc  func showPKToolKit(){
        let toolPicker = PKToolPicker.init()
        toolPicker.setVisible(true, forFirstResponder: canvasView)
        toolPicker.addObserver(canvasView)
        canvasView.becomeFirstResponder()
        self.canvasView.drawingPolicy = .anyInput
    }

}

这就是我的密码。
output video link
有人帮忙解决这个问题吗