detectAndDecodeMulti method
Detects QR codes in image, finds the quadrangles containing the codes, and decodes the QRCodes to strings.
Each quadrangle would be returned as a row in the points Mat and each point is a Vecf.
Returns true as long as some QR code was detected even in case where the decoding failed
For usage please see TestQRCodeDetector
For further details, please see:
https://docs.opencv.org/master/de/dc3/classcv_1_1QRCodeDetector.html#a188b63ffa17922b2c65d8a0ab7b70775
Implementation
(bool, List<String>, VecPoint, VecMat) detectAndDecodeMulti(InputArray img) {
  final info = VecVecChar();
  final points = VecPoint();
  final codes = VecMat();
  final rval = calloc<ffi.Bool>();
  cvRun(
    () => cobjdetect.cv_QRCodeDetector_detectAndDecodeMulti(
      ref,
      img.ref,
      info.ptr,
      points.ptr,
      codes.ptr,
      rval,
      ffi.nullptr,
    ),
  );
  final ret = (rval.value, info.asStringList(), points, codes);
  info.dispose();
  calloc.free(rval);
  return ret;
}