sortIdx function
SortIdx sorts each row or each column of a matrix. Instead of reordering the elements themselves, it stores the indices of sorted elements in the output array
For further details, please see: https://docs.opencv.org/master/d2/de8/group__core__array.html#gadf35157cbf97f3cb85a545380e383506
Implementation
Mat sortIdx(InputArray src, int flags, {OutputArray? dst}) {
dst ??= Mat.empty();
cvRun(() => ccore.cv_sortIdx(src.ref, dst!.ref, flags, ffi.nullptr));
return dst;
}