在UIScrollView中缩放UIImageView -不居中

import UIKit

class ViewController: UIViewController, UIScrollViewDelegate {
    var scrollView: UIScrollView!
    var imageView: UIImageView!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        scrollView = UIScrollView(frame: view.bounds)
        scrollView.delegate = self
        scrollView.contentSize = CGSize(width: 1000, height: 1000) // 设置contentSize以容纳UIImageView
        scrollView.minimumZoomScale = 0.5 // 设置最小缩放比例
        scrollView.maximumZoomScale = 2.0 // 设置最大缩放比例
        view.addSubview(scrollView)
        
        imageView = UIImageView(image: UIImage(named: "image.jpg"))
        scrollView.addSubview(imageView)
    }
    
    func viewForZooming(in scrollView: UIScrollView) -> UIView? {
        return imageView
    }
    
    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)
    }
}