In this app I get access to QRCode.
Reading works perfectly from the camera.
Now I am struggling to get the image that was processed by the built in QRCode reader.
I have found many hints on SO, but cannot make it work.
Here is the code I have now.
It is a bit long, I have to slit in 2 parts
I looked at:
// https://stackoverflow.com/questions/56088575/how-to-get-image-of-qr-code-after-scanning-in-swift-ios
// https://stackoverflow.com/questions/37869963/how-to-use-avcapturephotooutput
import UIKit
import AVFoundation
class ScannerViewController: UIViewController, AVCaptureMetadataOutputObjectsDelegate {
		fileprivate var captureSession: AVCaptureSession! // use for QRCode reading
		fileprivate var previewLayer: AVCaptureVideoPreviewLayer!
		
		// To get the image of the QRCode
		private var photoOutputQR: AVCapturePhotoOutput!
		private var isCapturing = false
		
		override func viewDidLoad() {
				super.viewDidLoad()
				var accessGranted = false
			 //	switch AVCaptureDevice.authorizationStatus(for: .video) {
// HERE TEST FOR ACCESS RIGHT. WORKS OK ;
// But is .video enough ?
				}
				
				if !accessGranted {	return }
				captureSession = AVCaptureSession()
				
				photoOutputQR = AVCapturePhotoOutput() // IS IT THE RIGHT PLACE AND THE RIGHT THING TO DO ?
				captureSession.addOutput(photoOutputQR)	 // Goal is to capture an image of QRCode once acquisition is done
				guard let videoCaptureDevice = AVCaptureDevice.default(for: .video) else { return }
				let videoInput: AVCaptureDeviceInput
				
				do {
						videoInput = try AVCaptureDeviceInput(device: videoCaptureDevice)
				} catch {	return }
				
				if (captureSession.canAddInput(videoInput)) {
						captureSession.addInput(videoInput)
				} else {
						failed()
						return
				}
				
				let metadataOutput = AVCaptureMetadataOutput()
				
				if (captureSession.canAddOutput(metadataOutput)) {
						captureSession.addOutput(metadataOutput) // SO I have 2 output in captureSession. IS IT RIGHT ?
						
						metadataOutput.setMetadataObjectsDelegate(self, queue: DispatchQueue.main)
						metadataOutput.metadataObjectTypes = [.qr]	// For QRCode video acquisition
						
				} else {
						failed()
						return
				}
				
				previewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
				previewLayer.frame = view.layer.bounds
				previewLayer.frame.origin.y += 40
				previewLayer.frame.size.height -= 40
				previewLayer.videoGravity = .resizeAspectFill
				view.layer.addSublayer(previewLayer)
				captureSession.startRunning()
		}
		
		override func viewWillAppear(_ animated: Bool) {
				
				super.viewWillAppear(animated)
				if (captureSession?.isRunning == false) {
						captureSession.startRunning()
				}
		}
		
		override func viewWillDisappear(_ animated: Bool) {
				
				super.viewWillDisappear(animated)
				if (captureSession?.isRunning == true) {
						captureSession.stopRunning()
				}
		}
		
		// MARK: - scan Results
		
		func metadataOutput(_ output: AVCaptureMetadataOutput, didOutput metadataObjects: [AVMetadataObject], from connection: AVCaptureConnection) {
				
				captureSession.stopRunning()
				
				if let metadataObject = metadataObjects.first {
						guard let readableObject = metadataObject as? AVMetadataMachineReadableCodeObject else { return }
						guard let stringValue = readableObject.stringValue else { return }
						AudioServicesPlaySystemSound(SystemSoundID(kSystemSoundID_Vibrate))
						found(code: stringValue)
				}
				// Get image - IS IT THE RIGHT PLACE TO DO IT ?
				// https://stackoverflow.com/questions/37869963/how-to-use-avcapturephotooutput
				print("Do I get here ?", isCapturing)
				let photoSettings = AVCapturePhotoSettings()
				let previewPixelType = photoSettings.availablePreviewPhotoPixelFormatTypes.first!
				print("previewPixelType", previewPixelType)
				let previewFormat = [kCVPixelBufferPixelFormatTypeKey as String: previewPixelType,
														 kCVPixelBufferWidthKey as String: 160,
														 kCVPixelBufferHeightKey as String: 160]
				photoSettings.previewPhotoFormat = previewFormat
				if !isCapturing {
						isCapturing = true
						photoOutputQR.capturePhoto(with: photoSettings, delegate: self)
				}
				dismiss(animated: true)
		}
		
}
extension ScannerViewController: AVCapturePhotoCaptureDelegate {
	
		func photoOutput(_ output: AVCapturePhotoOutput, didFinishProcessingPhoto photo: AVCapturePhoto, error: Error?) {
			
				isCapturing = false
				print("photo", photo, photo.fileDataRepresentation())
				guard let imageData = photo.fileDataRepresentation() else {
						print("Error while generating image from photo capture data.");
						return
				}
		 }
}
I get the following print on console
Clearly photo is not loaded properly
Do I get here ? false
previewPixelType 875704422
photo <AVCapturePhoto: 0x281973a20 pts:nan 1/1 settings:uid:3 photo:{0x0} time:nan-nan> nil
Error while generating image from photo capture data.
