当用户捏住屏幕时如何放大/缩小UIImage对象？

import UIKit

class ViewController: UIViewController {
    let imageView = UIImageView()
    let tapGesture = UITapGestureRecognizer()

    override func viewDidLoad() {
        super.viewDidLoad()

        // 添加 UIImageView
        imageView.image = UIImage(named: "example")
        imageView.frame = view.bounds
        imageView.contentMode = .scaleAspectFit
        view.addSubview(imageView)

        // 添加 UITapGestureRecognizer
        tapGesture.numberOfTapsRequired = 2
        tapGesture.addTarget(self, action: #selector(handleTap))
        view.addGestureRecognizer(tapGesture)
    }

    @objc func handleTap(sender: UITapGestureRecognizer) {
        // 放大或缩小 UIImage 对象
        if imageView.frame.size.width == view.frame.size.width {
            UIView.animate(withDuration: 0.3) {
                self.imageView.frame.size.width = self.view.frame.size.width * 2
                self.imageView.frame.size.height = self.view.frame.size.height * 2
                self.imageView.center = self.view.center
            }
        } else {
            UIView.animate(withDuration: 0.3) {
                self.imageView.frame.size.width = self.view.frame.size.width
                self.imageView.frame.size.height = self.view.frame.size.height
                self.imageView.center = self.view.center
            }
        }
    }
}