Implementing screen sharing

Swift

Expose the Root View for Full-Screen Capture

To capture the entire app screen, you need access to the root UIView. Add an extension:

UIApplication+rootViewController.swift

import UIKit

extension UIApplication {
    var rootViewController: UIViewController? {
        connectedScenes
            .compactMap { $0 as? UIWindowScene }
            .flatMap { $0.windows }
            .first { $0.isKeyWindow }?
            .rootViewController
    }
}

Then use:

guard let rootView = UIApplication.shared.rootViewController?.view else { return }
capturer = ScreenCapturer(withView: rootView)

Alternative path: Capture a specific region with UIViewRepresentable

In following steps we will show you to how to wire the rootView into the ScreenCapturer. However in case you prefer to capture a specific region of the screen - you can capture a specific UIView backed by SwiftUI. Create a UIViewRepresentable that produces the view you want to share, embed it in your layout, and pass its underlying UIView to the capturer (e.g. via a callback when makeUIView runs).

Example - a sharable time label:

import SwiftUI
import UIKit

struct TimeLabelView: UIViewRepresentable {
    let text: String
    private let labelTag = 1001

    func makeUIView(context: Context) -> UIView {
        let container = UIView()
        container.backgroundColor = .red

        let label = UILabel()
        label.tag = labelTag
        label.textAlignment = .center
        label.backgroundColor = .clear
        label.textColor = .white
        label.adjustsFontSizeToFitWidth = true

        label.translatesAutoresizingMaskIntoConstraints = false
        container.addSubview(label)

        NSLayoutConstraint.activate([
            label.leadingAnchor.constraint(equalTo: container.leadingAnchor),
            label.trailingAnchor.constraint(equalTo: container.trailingAnchor),
            label.topAnchor.constraint(equalTo: container.topAnchor),
            label.bottomAnchor.constraint(equalTo: container.bottomAnchor)
        ])

        return container
    }

    func updateUIView(_ uiView: UIView, context: Context) {
        (uiView.viewWithTag(labelTag) as? UILabel)?.text = text
    }
}

Display TimeLabelView in SwiftUI and wire its UIView into your manager (e.g. via @State and an onAppear / Coordinator), then pass that view to ScreenCapturer(withView:) to share only that region instead of the full screen.