尝试在图像中没有导航/状态栏的情况下拍摄相机卷的屏幕截图- Swift 3、Xcode 8、IOS

import UIKit
import AVFoundation

class ViewController: UIViewController {

    @IBOutlet weak var cameraView: UIView!
    var captureSession: AVCaptureSession?
    var stillImageOutput: AVCaptureStillImageOutput?
    var previewLayer: AVCaptureVideoPreviewLayer?

    override func viewDidLoad() {
        super.viewDidLoad()
        setupCaptureSession()
    }

    func setupCaptureSession() {
        captureSession = AVCaptureSession()
        captureSession?.sessionPreset = AVCaptureSession.Preset.photo

        guard let backCamera = AVCaptureDevice.default(for: AVMediaType.video) else {
            print("Unable to access back camera")
            return
        }

        do {
            let input = try AVCaptureDeviceInput(device: backCamera)
            stillImageOutput = AVCaptureStillImageOutput()

            if captureSession!.canAddInput(input) && captureSession!.canAddOutput(stillImageOutput!) {
                captureSession?.addInput(input)
                captureSession?.addOutput(stillImageOutput!)

                previewLayer = AVCaptureVideoPreviewLayer(session: captureSession!)
                previewLayer?.videoGravity = AVLayerVideoGravity.resizeAspectFill
                previewLayer?.connection?.videoOrientation = AVCaptureVideoOrientation.portrait
                cameraView.layer.addSublayer(previewLayer!)
                captureSession?.startRunning()
            }
        } catch {
            print("Error setting up capture session: \(error)")
        }
    }

    @IBAction func captureImage(_ sender: UIButton) {
        guard let videoConnection = stillImageOutput?.connection(with: AVMediaType.video) else {
            print("Unable to capture image")
            return
        }

        stillImageOutput?.captureStillImageAsynchronously(from: videoConnection, completionHandler: { (sampleBuffer, error) in
            if let buffer = sampleBuffer, let imageData = AVCaptureStillImageOutput.jpegStillImageNSDataRepresentation(buffer) {
                if let image = UIImage(data: imageData) {
                    UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil)
                }
            }
        })
    }
}