Barcode Detection

The Camera SDK has a built-in barcode detector that will help you identify different kind of barcodes in real-time. We support the following set of barcodes, exposed through the Barcode.Kind enumeration:

If your barcode is not on the list, please let us know - we may provide more options in the future.

Configuration

Requirements

Barcode detection works on all devices. The only requirement is to declare your intention to use it during manager initialization. We provide a special feature object called CameraFeature.BarcodeCameraFeature.barcode.

Barcode detection doesn't need a visible preview. You may use the barcode feature without CameraFeature.PreviewCameraFeature.preview and it will work out of the box.

To interact with all barcode APIs, you'll use the BarcodeDetector class:

swift
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let detector: BarcodeDetector = cameraManager.barcodeDetector

kotlin
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val detector: BarcodeDetector = cameraManager.barcodeDetector

Options

The BarcodeDetector.Options class and the BarcodeDetector.options field will let you configure the detection options, which can affect performance, amount and type of symbols to be retrieved and more.

swift
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let detector: BarcodeDetector = cameraManager.barcodeDetector
detector.options = Options(count: 3, kinds: [.qr, .microQr])

kotlin
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val detector: BarcodeDetector = cameraManager.barcodeDetector
detector.options = Options(count = 3, kinds = listOf(QR, MicroQR))

Disabling detection

Detection can be disabled in a number of ways:

• The CameraFeature.BarcodeCameraFeature.barcode was not set
• The Options value has a non-positive count
• The Options value has a negative interval
• The Options value has an empty kinds array
• The Options value has a non-empty surface, but no surface with that name exists

Disabling detection can be useful to save resources (CPU and battery) when not needed, for example while recording videos.

Observing barcodes

Once the barcode feature is declared and the CameraDevice is open, detection will start automatically. The barcode detector will then provide you with a sequence of one or more Barcode objects with the following properties:

There are two ways to receive Barcode updates:

• By reading barcode detector's state, which updates automatically
• By receiving barcode detection events

State

On every processed frame, BarcodeDetector will update its barcodes property which can be read to retrieve a list of Barcode objects. Note that in the majority of frames, the list will be empty. The list of barcodes can also be observed through the provided coroutines Flowthe provided publisher:

kotlin
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val detector: BarcodeDetector = cameraManager.barcodeDetector
val flow: StateFlow<List<Barcode>> = detector.barcodes

swift
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let detector: BarcodeDetector = cameraManager.barcodeDetector
let publisher: AnyPublisher<[Barcode], Never> = detector.barcodesPublisher

The stateful APIs are the recommended way to receive barcode updates to update the UI (e.g. draw the barcode box on screen), because you'll be able to receive position updates for a barcode that was initially detected in previous frames.

Events

In addition, you can register an observer lambda that will be executed for any new barcode, as soon as it is found. The difference with the previous approach is that you won't get duplicate updates: if a Barcode is detected on frames i, i + 1, .... i + 100 you'll only get the event on frame i.

This mode can be useful if all you care about is the barcode contents. Remember to return true to continue receiving updates, and false to remove the observer:

kotlin
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val detector: BarcodeDetector = cameraManager.barcodeDetector
detector.observe { barcode ->
   // Handle barcode...
   true // Keep observing
}

swift
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let detector: BarcodeDetector = cameraManager.barcodeDetector
detector.observe { barcode in
   // Handle barcode...
   return true // Keep observing
}