threshold function

(double, Mat) threshold(
  1. InputArray src,
  2. double thresh,
  3. double maxval,
  4. int type, {
  5. OutputArray? dst,
  6. InputArray? mask,
})

Threshold applies a fixed-level threshold to each array element.

Note This function also supports thresholdWithMask If the mask is empty, thresholdWithMask is equivalent to threshold. If the mask is not empty, dst must be of the same size and type as src, so that outliers pixels are left as-is.

For further details, please see: https:///docs.opencv.org/3.3.0/d7/d1b/group__imgproc__misc.html#gae8a4a146d1ca78c626a53577199e9c57

Implementation

(double, Mat dst) threshold(
  InputArray src,
  double thresh,
  double maxval,
  int type, {
  OutputArray? dst,
  InputArray? mask,
}) {
  dst ??= mask == null ? Mat.empty() : Mat.zeros(src.rows, src.cols, src.type);
  final p = calloc<ffi.Double>();
  cvRun(
    () => mask == null
        ? cimgproc.cv_threshold(src.ref, dst!.ref, thresh, maxval, type, p, ffi.nullptr)
        : cimgproc.cv_thresholdWithMask(src.ref, dst!.ref, mask.ref, thresh, maxval, type, p, ffi.nullptr),
  );
  final rval = (p.value, dst);
  calloc.free(p);
  return rval;
}