如何将滑动ImageView实现为Eureka表单上的页眉

import UIKit
import Eureka

class CustomFormViewController: FormViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 设置代理
        self.tableView.delegate = self
    }
}

extension CustomFormViewController {
    
    // 返回自定义的HeaderView
    override func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
        let headerView = UIView()
        
        // 添加ImageView
        let imageView = UIImageView(image: UIImage(named: "your_image"))
        imageView.contentMode = .scaleAspectFill
        imageView.translatesAutoresizingMaskIntoConstraints = false
        headerView.addSubview(imageView)
        
        // 设置约束
        NSLayoutConstraint.activate([
            imageView.topAnchor.constraint(equalTo: headerView.topAnchor),
            imageView.leadingAnchor.constraint(equalTo: headerView.leadingAnchor),
            imageView.trailingAnchor.constraint(equalTo: headerView.trailingAnchor),
            imageView.bottomAnchor.constraint(equalTo: headerView.bottomAnchor)
        ])
        
        return headerView
    }
    
    // 根据滑动偏移量更新ImageView的位置或大小
    override func scrollViewDidScroll(_ scrollView: UIScrollView) {
        guard let headerView = tableView.headerView(forSection: 0) else { return }
        
        let offsetY = scrollView.contentOffset.y
        let headerHeight = headerView.frame.height
        
        // 根据需要调整ImageView的位置或大小
        // 例如：根据滑动偏移量改变ImageView的透明度
        let alpha = 1 - (offsetY / headerHeight)
        headerView.alpha = alpha
    }
}