Custom Barcode Scanner, tap to focus - ios

Question

Referencing these questions here:
How to implement tap to focus on barcode scanner app using swift?
Set Camera Focus On Tap Point With Swift
https://stackoverflow.com/a/41796603/8272698
The links above are quite old and out of date. I have tried to use the answers provided above but to no avail... below is my attempt from them..
I need to tap my screen when reading barcodes to implement a focus on the object in the view.
Here is my code attempt
var captureDevice: AVCaptureDevice? //capture device Is this right?
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
let screenSize = videoPreviewLayer!.bounds.size
if let touchPoint = touches.first {
let x = touchPoint.location(in: self.view).y / screenSize.height
let y = 1.0 - touchPoint.location(in: self.view).x / screenSize.width
let focusPoint = CGPoint(x: x, y: y)
if let device = captureDevice {
do {
try device.lockForConfiguration()
device.focusPointOfInterest = focusPoint
//device.focusMode = .continuousAutoFocus
device.focusMode = .autoFocus
//device.focusMode = .locked
device.exposurePointOfInterest = focusPoint
device.exposureMode = AVCaptureDevice.ExposureMode.continuousAutoExposure
device.unlockForConfiguration()
}
catch {
// just ignore
}
}
}
}
This code doesn't work as when I tap no focusing happens.
Here is the rest of my camera code.
import UIKit
import AVFoundation
class BarcodeScanVC: UIViewController {
struct GlobalVariable{
static var senderTags = 0
}
var captureSession = AVCaptureSession()
var videoPreviewLayer: AVCaptureVideoPreviewLayer?
var qrCodeFrameView: UIView?
var row = 0
var senderTag = 0
var waybillData: String = ""
var diagnosticErrorCodeData: String = ""
var hddSerialNumberData: String = ""
var scanRectView: UIView?
var delegate: BarcodeScanDelegate?
var captureDevice: AVCaptureDevice?
private let supportedCodeTypes = [AVMetadataObject.ObjectType.upce,
AVMetadataObject.ObjectType.code39,
AVMetadataObject.ObjectType.code39Mod43,
AVMetadataObject.ObjectType.code93,
AVMetadataObject.ObjectType.code128,
AVMetadataObject.ObjectType.ean8,
AVMetadataObject.ObjectType.ean13,
AVMetadataObject.ObjectType.aztec,
AVMetadataObject.ObjectType.pdf417,
AVMetadataObject.ObjectType.itf14,
AVMetadataObject.ObjectType.dataMatrix,
AVMetadataObject.ObjectType.interleaved2of5,
AVMetadataObject.ObjectType.qr]
override func viewDidLoad() {
super.viewDidLoad()
// Get the back-facing camera for capturing videos
//let deviceDiscoverySession = AVCaptureDevice.DiscoverySession(deviceTypes: [.builtInDualCamera], mediaType: AVMediaType.video, position: .back)
let deviceDiscoverySession = AVCaptureDevice.DiscoverySession(deviceTypes: [.builtInWideAngleCamera], mediaType: AVMediaType.video, position: .back)
guard let captureDevice = deviceDiscoverySession.devices.first else {
print("Failed to get the camera device")
return
}
do {
// Get an instance of the AVCaptureDeviceInput class using the previous device object.
let input = try AVCaptureDeviceInput(device: captureDevice)
// Set the input device on the capture session.
captureSession.addInput(input)
// Initialize a AVCaptureMetadataOutput object and set it as the output device to the capture session.
let captureMetadataOutput = AVCaptureMetadataOutput()
captureSession.addOutput(captureMetadataOutput)
// Set delegate and use the default dispatch queue to execute the call back
captureMetadataOutput.setMetadataObjectsDelegate(self, queue: DispatchQueue.main)
captureMetadataOutput.metadataObjectTypes = supportedCodeTypes
// captureMetadataOutput.metadataObjectTypes = [AVMetadataObject.ObjectType.qr]
} catch {
// If any error occurs, simply print it out and don't continue any more.
print(error)
return
}
captureSession.commitConfiguration()
// Initialize the video preview layer and add it as a sublayer to the viewPreview view's layer.
videoPreviewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
videoPreviewLayer?.videoGravity = AVLayerVideoGravity.resizeAspectFill
videoPreviewLayer?.frame = view.layer.bounds
//videoPreviewLayer?.frame
// let height: CGFloat = ((videoPreviewLayer?.frame.size.width)!)/2
// let width: CGFloat = ((videoPreviewLayer?.frame.size.width)!)/2
let height: CGFloat = (view.frame.size.height)/2
let width: CGFloat = (view.frame.size.width) - 200
let path = UIBezierPath()
//Corner1
path.move(to: CGPoint(x: 5, y: 50))
path.addLine(to: CGPoint(x: 5, y: 5))
path.addLine(to: CGPoint(x: 50, y: 5))
//Corner2
path.move(to: CGPoint(x: height - 55, y: 5))
path.addLine(to: CGPoint(x: height - 5, y: 5))
path.addLine(to: CGPoint(x: height - 5, y: 55))
//Corner3
path.move(to: CGPoint(x: 5, y: width - 55))
path.addLine(to: CGPoint(x: 5, y: width - 5))
path.addLine(to: CGPoint(x: 55, y: width - 5))
//Corner4 -bottom right
path.move(to: CGPoint(x: height - 5, y: width - 55))
path.addLine(to: CGPoint(x: height - 5, y: width - 5))
path.addLine(to: CGPoint(x: height - 55, y: width - 5))
let shape = CAShapeLayer()
shape.path = path.cgPath
shape.strokeColor = UIColor.white.cgColor
shape.lineWidth = 5
shape.frame.origin.x = 20
shape.frame.origin.y = 180
shape.fillColor = UIColor.clear.cgColor
videoPreviewLayer?.addSublayer(shape)
view.layer.addSublayer(videoPreviewLayer!)
//videoPreviewLayer?.anchorPoint.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
//view.layer.addSublayer(scanRectView)
// Start video capture.
captureSession.startRunning()
// Move the message label and top bar to the front
//view.bringSubview(toFront: messageLabel)
//view.bringSubview(toFront: topbar)
// Initialize QR Code Frame to highlight the QR code
qrCodeFrameView = UIView()
if let qrCodeFrameView = qrCodeFrameView {
qrCodeFrameView.layer.borderColor = UIColor.green.cgColor
qrCodeFrameView.layer.borderWidth = 2
view.addSubview(qrCodeFrameView)
view.bringSubviewToFront(qrCodeFrameView)
}
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
let screenSize = videoPreviewLayer!.bounds.size
if let touchPoint = touches.first {
let x = touchPoint.location(in: self.view).y / screenSize.height
let y = 1.0 - touchPoint.location(in: self.view).x / screenSize.width
let focusPoint = CGPoint(x: x, y: y)
if let device = captureDevice {
do {
try device.lockForConfiguration()
device.focusPointOfInterest = focusPoint
//device.focusMode = .continuousAutoFocus
device.focusMode = .autoFocus
//device.focusMode = .locked
device.exposurePointOfInterest = focusPoint
device.exposureMode = AVCaptureDevice.ExposureMode.continuousAutoExposure
device.unlockForConfiguration()
}
catch {
// just ignore
}
}
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func launchApp(barcodeScan: String) {
// if presentedViewController != nil {
// return
// }
guard presentedViewController == nil else {
return
}
let alertPrompt = UIAlertController(title: "Barcode Found", message: "\(barcodeScan)", preferredStyle: .actionSheet)
let confirmAction = UIAlertAction(title: "Confirm", style: UIAlertAction.Style.default, handler: { (action) -> Void in
if self.senderTag == 1 {
GlobalVariable.senderTags = 1
self.delegate?.didScan(barcodeData: barcodeScan)
self.navigationController?.popViewController(animated: true)
}
if self.senderTag == 2 {
GlobalVariable.senderTags = 2
self.delegate?.didScan(barcodeData: barcodeScan)
self.navigationController?.popViewController(animated: true)
}
if self.senderTag == 3 {
GlobalVariable.senderTags = 3
self.delegate?.didScan(barcodeData: barcodeScan)
self.navigationController?.popViewController(animated: true)
}
if self.senderTag != 1 && self.senderTag != 2 && self.senderTag != 3 {
let indexPath = IndexPath(row: self.row, section: 0)
let cell: PartsOrderRequestTableCell = globalPartsOrderRequestTableVC?.tableView.cellForRow(at: indexPath) as! PartsOrderRequestTableCell
cell.diagnosticCodeLabel.text = barcodeScan
cell.diagnosticCodeLabel.endEditing(true)
self.navigationController?.popViewController(animated: true)
//return
}
})
let cancelAction = UIAlertAction(title: "Cancel", style: UIAlertAction.Style.cancel, handler: nil)
alertPrompt.addAction(confirmAction)
alertPrompt.addAction(cancelAction)
present(alertPrompt, animated: true, completion: nil)
}
}
extension BarcodeScanVC: AVCaptureMetadataOutputObjectsDelegate {
func metadataOutput(_ output: AVCaptureMetadataOutput, didOutput metadataObjects: [AVMetadataObject], from connection: AVCaptureConnection) {
// Check if the metadataObjects array is not nil and it contains at least one object.
if metadataObjects.count == 0 {
qrCodeFrameView?.frame = CGRect.zero
//messageLabel.text = "No QR code is detected"
return
}
// Get the metadata object.
let metadataObj = metadataObjects[0] as! AVMetadataMachineReadableCodeObject
if supportedCodeTypes.contains(metadataObj.type) {
// If the found metadata is equal to the QR code metadata (or barcode) then update the status label's text and set the bounds
let barCodeObject = videoPreviewLayer?.transformedMetadataObject(for: metadataObj)
qrCodeFrameView?.frame = barCodeObject!.bounds
if metadataObj.stringValue != nil {
launchApp(barcodeScan: metadataObj.stringValue!)
//messageLabel.text = metadataObj.stringValue
}
}
}
private func updatePreviewLayer(layer: AVCaptureConnection, orientation: AVCaptureVideoOrientation) {
layer.videoOrientation = orientation
videoPreviewLayer?.frame = self.view.bounds
}
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
if let connection = self.videoPreviewLayer?.connection {
let currentDevice: UIDevice = UIDevice.current
let orientation: UIDeviceOrientation = currentDevice.orientation
let previewLayerConnection : AVCaptureConnection = connection
if previewLayerConnection.isVideoOrientationSupported {
switch (orientation) {
case .portrait: updatePreviewLayer(layer: previewLayerConnection, orientation: .portrait)
break
case .landscapeRight: updatePreviewLayer(layer: previewLayerConnection, orientation: .landscapeLeft)
break
case .landscapeLeft: updatePreviewLayer(layer: previewLayerConnection, orientation: .landscapeRight)
break
case .portraitUpsideDown: updatePreviewLayer(layer: previewLayerConnection, orientation: .portraitUpsideDown)
break
default: updatePreviewLayer(layer: previewLayerConnection, orientation: .portrait)
break
}
}
}
}
}
Am I missing something obvious ?
Is there a simple answer to this without changing much of the code I already have?
Thanks!

Answer 1

You're on the right track. It's getting stuck at
if let device = captureDevice
captureDevice is always nil at that point. You're setting it locally in viewDidLoad but nowhere the touchesBegan method can access it.
guard let captureDevice = deviceDiscoverySession.devices.first else {
print("Failed to get the camera device")
return
}
Change your code from the guard let captureDevice for something like:
captureDevice = deviceDiscoverySession.devices.first
and when you use captureDevice, test for nil when you need to.
EDIT:
override func viewDidLoad() {
super.viewDidLoad()
// Get the back-facing camera for capturing videos
//let deviceDiscoverySession = AVCaptureDevice.DiscoverySession(deviceTypes: [.builtInDualCamera], mediaType: AVMediaType.video, position: .back)
let deviceDiscoverySession = AVCaptureDevice.DiscoverySession(deviceTypes: [.builtInWideAngleCamera], mediaType: AVMediaType.video, position: .back)
captureDevice = deviceDiscoverySession.devices.first
if let captureDevice = captureDevice {
do {
// Get an instance of the AVCaptureDeviceInput class using the previous device object.
let input = try AVCaptureDeviceInput(device: captureDevice)
// Set the input device on the capture session.
captureSession.addInput(input)
// Initialize a AVCaptureMetadataOutput object and set it as the output device to the capture session.
let captureMetadataOutput = AVCaptureMetadataOutput()
captureSession.addOutput(captureMetadataOutput)
// Set delegate and use the default dispatch queue to execute the call back
captureMetadataOutput.setMetadataObjectsDelegate(self, queue: DispatchQueue.main)
captureMetadataOutput.metadataObjectTypes = supportedCodeTypes
// captureMetadataOutput.metadataObjectTypes = [AVMetadataObject.ObjectType.qr]
} catch {
// If any error occurs, simply print it out and don't continue any more.
print(error)
return
}
}
..... Method cut short as no other changes.