问如何在通过UIActivityView共享时给屏幕截图文件取一个文件名

EN

import UIKit

class EvenPrintableViewController: UIViewController {

@IBOutlet weak var widthSizeTransfer: UILabel!
@IBOutlet weak var heightSizeTransfer: UILabel!
@IBOutlet weak var lengthTransfer: UILabel!
@IBOutlet weak var calcOutput: UILabel!

// Instantiate variables for Even transfer
var largeSizeRelay: String?
var lengthSizeRelay: String?
var heightRelay: String?
var calcOutputRelay: String?

override func viewDidLoad() {
    super.viewDidLoad()
    
    // Sets share icon to share/print view
    navigationItem.rightBarButtonItem = UIBarButtonItem(barButtonSystemItem: .action, target: self, action: #selector(shareTapped))
    
    // Assign labels to Metric Even VC values via instances above
    widthSizeTransfer.text = witdhSizeRelay
    heightSizeTransfer.text = heightSizeRelay
    heightTransfer.text = heightRelay
    calcOutput.text = calcOutputRelay

}

// Share function for share button
@objc func shareTapped() {
    
    let renderer = UIGraphicsImageRenderer(size: view.bounds.size)
    let image = renderer.image { ctx in
        view.drawHierarchy(in: view.bounds, afterScreenUpdates: true)
    }

    let vc = UIActivityViewController(activityItems: [image], applicationActivities: [])
    vc.excludedActivityTypes = [.assignToContact, .addToReadingList]
    vc.popoverPresentationController?.barButtonItem = navigationItem.rightBarButtonItem
    present(vc, animated: true)
}
}