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Get Started

In this guide you will learn step-by-step how to add Barcode Capture to your application.

The general steps are:

  • Creating a new Data Capture Context instance
  • Create your barcode capture settings and enable the barcode symbologies you want to read
  • Create a new barcode capture mode instance and initialize it
  • Register a barcode capture listener to receive scan events
  • Process successful scans according to your application’s needs and decide whether more codes will be scanned or the scanning process should be stopped
  • Obtain a camera instance and set it as the frame source on the data capture context
  • Display the camera preview by creating a data capture view
  • If displaying a preview, optionally create a new overlay and add it to data capture view for better visual feedback

Prerequisites​

Before starting with adding a capture mode, make sure that you have a valid Scandit Data Capture SDK license key and that you added the necessary dependencies. If you have not done that yet, check out this guide.

note

You can retrieve your Scandit Data Capture SDK license key, by signing in to your account Dashboard.

Create a Data Capture Context​

The first step to add capture capabilities to your application is to create a new Data Capture Context. The context expects a valid Scandit Data Capture SDK license key during construction.

self.context = DataCaptureContext(licenseKey: "-- ENTER YOUR SCANDIT LICENSE KEY HERE --")

Configure Barcode Scanning Settings​

Barcode scanning is orchestrated by the SDCBarcodeCapture data capture mode. This class is the main entry point for scanning barcodes. It is configured through SDCBarcodeCaptureSettings and allows you to register one or more listeners that will get informed whenever new codes have been recognized.

Here we will setup barcode scanning for a small list of barcode types, called symbologies. The list of symbologies to enable is application specific. We recommend that you only enable the symbologies your application requires. If you are not familiar with the symbologies that are relevant for your use case, you can use capture presets that are tailored for different verticals (e.g. retail, logistics).

let settings = BarcodeCaptureSettings()
settings.set(symbology: .code128, enabled: true)
settings.set(symbology: .code39, enabled: true)
settings.set(symbology: .qr, enabled: true)
settings.set(symbology: .ean8, enabled: true)
settings.set(symbology: .upce, enabled: true)
settings.set(symbology: .ean13UPCA, enabled: true)
note

If you are not disabling barcode capture immediately after having scanned the first code, consider setting the SDCBarcodeCaptureSettings.codeDuplicateFilter to around 500 or even -1 if you do not want codes to be scanned more than once.

Next, create a SDCBarcodeCapture instance with the settings initialized in the previous step:

barcodeCapture = BarcodeCapture(context: context, settings: settings)

Register the Barcode Capture Listener​

To get informed whenever a new code has been recognized, add a SDCBarcodeCaptureListener through SDCBarcodeCapture.addListener: and implement the listener methods to suit your application’s needs.

First conform to the SDCBarcodeCaptureListener protocol. For example:

extension ViewController: BarcodeCaptureListener {
  func barcodeCapture(_ barcodeCapture: BarcodeCapture,
                   didScanIn session: BarcodeCaptureSession,
                   frameData: FrameData) {
        let recognizedBarcodes = session.newlyRecognizedBarcode
        for barcode in recognizedBarcodes {
            // Do something with the barcode.
        }
    }
}

Then add the listener:

barcodeCapture.addListener(self)

Use the Built-in Camera​

The data capture context supports using different frame sources to perform recognition on. Most applications will use the built-in camera of the device.

note

In iOS, the user must explicitly grant permission for each app to access cameras. Your app needs to provide static messages to display to the user when the system asks for camera permission. To do that include the NSCameraUsageDescription key in your app’s Info.plist file.

When using the built-in camera there are recommended settings for each capture mode. These should be used to achieve the best performance and user experience for the respective mode. The following couple of lines show how to get the recommended settings and create the camera from it:

let cameraSettings = BarcodeCapture.recommendedCameraSettings

// Depending on the use case further camera settings adjustments can be made here.

let camera = Camera.default
camera?.apply(cameraSettings)

Because the frame source is configurable, the data capture context must be told which frame source to use. This is done with a call to SDCDataCaptureContext.setFrameSource:completionHandler:.

The camera is off by default and must be turned on. This is done by calling SDCFrameSource.switchToDesiredState:completionHandler: with a value of SDCFrameSourceStateOn:

context.setFrameSource(camera)


camera?.switch(toDesiredState: .on)

Use a Capture View to Visualize the Scan Process​

When using the built-in camera as frame source, you will typically want to display the camera preview on the screen together with UI elements that guide the user through the capturing process. To do that, add a SDCDataCaptureView to your view hierarchy:

let captureView = DataCaptureView(for: context, frame: view.bounds)
captureView.dataCaptureContext = context
captureView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
view.addSubview(captureView)
To visualize the results of barcode scanning, the following overlay can be added:

let overlay = BarcodeCaptureOverlay(barcodeCapture: barcodeCapture, view: captureView)

Disabling Barcode Capture​

To disable barcode capture, for instance as a consequence of a barcode being recognized, set SDCBarcodeCapture.enabled to NO.

The effect is immediate: no more frames will be processed after the change. However, if a frame is currently being processed, this frame will be completely processed and deliver any results/callbacks to the registered listeners. Note that disabling the capture mode does not stop the camera, the camera continues to stream frames until it is turned off.