Zxing Android decode QR code

DecodeQRCode.kt

fun Bitmap.decodeQR(): String? {
    val width = width
    val height = height
    val pixels = IntArray(width * height)
    getPixels(pixels, 0, width, 0, 0, width, height)

    val source = RGBLuminanceSource(width, height, pixels)
    val binaryBitmap = BinaryBitmap(GlobalHistogramBinarizer(source))
    val reader = MultiFormatReader()
    val hints = EnumMap<DecodeHintType, Any>(DecodeHintType::class.java)
    hints[DecodeHintType.TRY_HARDER] = true
    hints[DecodeHintType.POSSIBLE_FORMATS] = EnumSet.allOf(BarcodeFormat::class.java)

    val results = ArrayList<Result>(1)
    var readException: ReaderException? = null
    try {
        val multiReader = GenericMultipleBarcodeReader(reader)
        val theResults = multiReader.decodeMultiple(binaryBitmap, hints)
        if (theResults != null) {
            results.addAll(theResults)
        }
    } catch (e: ReaderException) {
        readException = e
    }

    if (results.isEmpty()) {
        try {
            val hintsPure = EnumMap<DecodeHintType, Any>(hints)
            hintsPure[DecodeHintType.PURE_BARCODE] = true
            val theResult = reader.decode(binaryBitmap, hintsPure)
            if (theResult != null) {
                results.add(theResult)
            }
        } catch (e: ReaderException) {
            readException = e
        }
    }

    if (results.isEmpty()) {
        try {
            val hybridBitmap = BinaryBitmap(HybridBinarizer(source))
            val theResult = reader.decode(hybridBitmap, hints)
            if (theResult != null) {
                results.add(theResult);
            }
        } catch (e: ReaderException) {
            readException = e
        }
    }

    if (results.isEmpty()) {
        readException?.printStackTrace()
        return null
    }

    return results[0].text  // optional
}