同步缩放两个UIScrollViews。

class ViewController: UIViewController, UIScrollViewDelegate {
    var scrollView1: UIScrollView!
    var scrollView2: UIScrollView!
    var displayLink: CADisplayLink?

    override func viewDidLoad() {
        super.viewDidLoad()
        
        scrollView1 = UIScrollView(frame: CGRect(x: 0, y: 0, width: view.bounds.width, height: view.bounds.height / 2))
        scrollView2 = UIScrollView(frame: CGRect(x: 0, y: view.bounds.height / 2, width: view.bounds.width, height: view.bounds.height / 2))
        
        scrollView1.delegate = self
        scrollView2.delegate = self
        
        view.addSubview(scrollView1)
        view.addSubview(scrollView2)
        
        // 设置初始内容大小和缩放比例
        scrollView1.contentSize = CGSize(width: 1000, height: 500)
        scrollView2.contentSize = CGSize(width: 1000, height: 500)
        scrollView1.minimumZoomScale = 1.0
        scrollView2.minimumZoomScale = 1.0
        scrollView1.maximumZoomScale = 3.0
        scrollView2.maximumZoomScale = 3.0
    }
    
    func scrollViewDidZoom(_ scrollView: UIScrollView) {
        if scrollView === scrollView1 {
            scrollView2.zoomScale = scrollView1.zoomScale
        } else if scrollView === scrollView2 {
            scrollView1.zoomScale = scrollView2.zoomScale
        }
    }
    
    func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        displayLink?.invalidate()
    }
}