使用Swift在UIScrollView上设置zoomScale动画

import UIKit

class ViewController: UIViewController, UIScrollViewDelegate {
    @IBOutlet weak var scrollView: UIScrollView!
    var imageView: UIImageView!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 创建UIScrollView对象
        scrollView.delegate = self
        scrollView.contentSize = CGSize(width: 800, height: 800)
        
        // 添加需要展示的内容
        imageView = UIImageView(image: UIImage(named: "image.jpg"))
        scrollView.addSubview(imageView)
        
        // 设置UIScrollView的缩放范围
        scrollView.minimumZoomScale = 1.0
        scrollView.maximumZoomScale = 3.0
        
        // 添加手势识别器，用于双击缩放
        let doubleTapGesture = UITapGestureRecognizer(target: self, action: #selector(handleDoubleTap(_:)))
        doubleTapGesture.numberOfTapsRequired = 2
        scrollView.addGestureRecognizer(doubleTapGesture)
    }
    
    // UIScrollViewDelegate方法，返回需要缩放的视图
    func viewForZooming(in scrollView: UIScrollView) -> UIView? {
        return imageView
    }
    
    // 双击手势处理方法，实现双击放大或缩小
    @objc func handleDoubleTap(_ gesture: UITapGestureRecognizer) {
        if scrollView.zoomScale == scrollView.minimumZoomScale {
            // 双击放大
            let zoomRect = zoomRectForScale(scale: scrollView.maximumZoomScale, center: gesture.location(in: gesture.view))
            scrollView.zoom(to: zoomRect, animated: true)
        } else {
            // 双击缩小
            scrollView.setZoomScale(scrollView.minimumZoomScale, animated: true)
        }
    }
    
    // 根据缩放比例和中心点计算缩放区域
    func zoomRectForScale(scale: CGFloat, center: CGPoint) -> CGRect {
        var zoomRect = CGRect.zero
        zoomRect.size.height = scrollView.frame.size.height / scale
        zoomRect.size.width = scrollView.frame.size.width / scale
        zoomRect.origin.x = center.x - (zoomRect.size.width / 2.0)
        zoomRect.origin.y = center.y - (zoomRect.size.height / 2.0)
        return zoomRect
    }
}