FaceDetector.kt

FaceDetector.kt

class FaceDetector(private val callback: DetectorCallback?) : IFrameProcessor {

    interface DetectorCallback {
        fun onSuccess(frameData: ByteBuffer, results: List<FirebaseVisionFace>, frameMetadata: FrameMetadata)
        fun onFailure(exception: Exception)
    }

    companion object {
        private const val TAG = "FaceDetector"
    }

    private val delegateDetector = FirebaseVision.getInstance()
        .getVisionFaceDetector(
            FirebaseVisionFaceDetectorOptions.Builder()
                .setLandmarkMode(FirebaseVisionFaceDetectorOptions.ALL_LANDMARKS)
                .build()
        )

    // To keep the latest images and its metadata.
    @GuardedBy("this")
    private var latestImage: ByteBuffer? = null

    @GuardedBy("this")
    private var latestImageMetaData: FrameMetadata? = null

    // To keep the images and metadata in process.
    @GuardedBy("this")
    private var processingImage: ByteBuffer? = null

    @GuardedBy("this")
    private var processingMetaData: FrameMetadata? = null

    @Synchronized
    override fun process(data: ByteBuffer, frameMetadata: FrameMetadata) {
        latestImage = data
        latestImageMetaData = frameMetadata
        if (processingImage == null && processingMetaData == null) {
            processLatestImage()
        }
    }

    @Synchronized
    private fun processLatestImage() {
        processingImage = latestImage
        processingMetaData = latestImageMetaData
        latestImage = null
        latestImageMetaData = null
        if (processingImage != null && processingMetaData != null) {
            processImage(processingImage!!, processingMetaData!!)
        }
    }

    private fun processImage(data: ByteBuffer, frameMetadata: FrameMetadata) {
        val metadata = FirebaseVisionImageMetadata.Builder()
            .setFormat(FirebaseVisionImageMetadata.IMAGE_FORMAT_NV21)
            .setWidth(frameMetadata.width)
            .setHeight(frameMetadata.height)
            .setRotation(frameMetadata.rotation)
            .build()

        val image = FirebaseVisionImage.fromByteBuffer(data, metadata)

        delegateDetector.detectInImage(image)
            .addOnSuccessListener { results ->
                callback?.onSuccess(data, results, frameMetadata)
                processLatestImage()
            }
            .addOnFailureListener { e ->
                callback?.onFailure(e)
            }
    }

    override fun stop() {
        try {
            delegateDetector.close()
        } catch (e: IOException) {
            Log.e(TAG, "Exception thrown while trying to close Face Detector: $e")
        }
    }

}