如何使用UIPanGestureRecognizer设置拖动控件的边界？

import UIKit

class ViewController: UIViewController {
    var draggableView: UIView!
    var panGestureRecognizer: UIPanGestureRecognizer!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 创建可拖动的视图
        draggableView = UIView(frame: CGRect(x: 100, y: 100, width: 100, height: 100))
        draggableView.backgroundColor = UIColor.red
        view.addSubview(draggableView)
        
        // 创建拖动手势识别器
        panGestureRecognizer = UIPanGestureRecognizer(target: self, action: #selector(handlePan(_:)))
        draggableView.addGestureRecognizer(panGestureRecognizer)
    }
    
    @objc func handlePan(_ gestureRecognizer: UIPanGestureRecognizer) {
        let translation = gestureRecognizer.translation(in: view)
        
        // 更新视图位置
        var newX = draggableView.center.x + translation.x
        var newY = draggableView.center.y + translation.y
        
        // 判断是否超出边界
        let minX = draggableView.bounds.width / 2
        let minY = draggableView.bounds.height / 2
        let maxX = view.bounds.width - draggableView.bounds.width / 2
        let maxY = view.bounds.height - draggableView.bounds.height / 2
        
        newX = max(minX, min(newX, maxX))
        newY = max(minY, min(newY, maxY))
        
        draggableView.center = CGPoint(x: newX, y: newY)
        
        gestureRecognizer.setTranslation(CGPoint.zero, in: view)
    }
}