如何在UIScrollView中实现图像缩放？

class ViewController: UIViewController, UIScrollViewDelegate {
    var scrollView: UIScrollView!
    var imageView: UIImageView!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 创建UIScrollView对象
        scrollView = UIScrollView(frame: view.bounds)
        scrollView.delegate = self
        scrollView.contentSize = imageView.bounds.size
        scrollView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
        
        // 创建UIImageView对象
        imageView = UIImageView(image: UIImage(named: "image.jpg"))
        imageView.frame = scrollView.bounds
        imageView.contentMode = .scaleAspectFit
        
        // 将UIImageView添加为UIScrollView的子视图
        scrollView.addSubview(imageView)
        
        // 设置UIScrollView的缩放范围
        scrollView.minimumZoomScale = 1.0
        scrollView.maximumZoomScale = 3.0
        
        // 将UIScrollView添加到视图层级中
        view.addSubview(scrollView)
    }
    
    // 返回要缩放的UIImageView对象
    func viewForZooming(in scrollView: UIScrollView) -> UIView? {
        return imageView
    }
    
    // 调整图像的位置和大小
    func scrollViewDidZoom(_ scrollView: UIScrollView) {
        let offsetX = max((scrollView.bounds.width - scrollView.contentSize.width) * 0.5, 0)
        let offsetY = max((scrollView.bounds.height - scrollView.contentSize.height) * 0.5, 0)
        imageView.center = CGPoint(x: scrollView.contentSize.width * 0.5 + offsetX, y: scrollView.contentSize.height * 0.5 + offsetY)
    }
}