如何使用UIImageView调整图片大小以便我可以放大和缩小？

import UIKit

class ViewController: UIViewController {
    let imageView = UIImageView()

    override func viewDidLoad() {
        super.viewDidLoad()

        imageView.image = UIImage(named: "your_image_name")
        imageView.frame = CGRect(x: 0, y: 0, width: 100, height: 100)
        imageView.center = view.center
        imageView.contentMode = .scaleAspectFit
        view.addSubview(imageView)
    }
}

class ViewController: UIViewController {
    let imageView = UIImageView()
    var lastScale: CGFloat = 1.0

    override func viewDidLoad() {
        super.viewDidLoad()

        imageView.image = UIImage(named: "your_image_name")
        imageView.frame = CGRect(x: 0, y: 0, width: 100, height: 100)
        imageView.center = view.center
        imageView.contentMode = .scaleAspectFit
        view.addSubview(imageView)

        let pinchGesture = UIPinchGestureRecognizer(target: self, action: #selector(pinchAction(sender:)))
        imageView.addGestureRecognizer(pinchGesture)
        imageView.isUserInteractionEnabled = true
    }

    @objc func pinchAction(sender: UIPinchGestureRecognizer) {
        switch sender.state {
        case .began, .changed:
            let scale = sender.scale
            imageView.transform = imageView.transform.scaledBy(x: scale, y: scale)
            sender.scale = 1.0
        default:
            break
        }
    }
}