row method

Mat row(
  1. int y
)

Creates a matrix header for the specified matrix row.

The method makes a new header for the specified matrix row and returns it. This is an O(1) operation, regardless of the matrix size. The underlying data of the new matrix is shared with the original matrix. Here is the example of one of the classical basic matrix processing operations, axpy, used by LU and many other algorithms:

inline void matrix_axpy(Mat& A, int i, int j, double alpha)
{
    A.row(i) += A.row(j)*alpha;
}

https://docs.opencv.org/4.x/d3/d63/classcv_1_1Mat.html#a4b22e1c23af7a7f2eef8fa478cfa7434

Implementation

Mat row(int y) {
  final p = calloc<cvg.Mat>();
  cvRun(() => cffi.Mat_Row(ref, y, p));
  return Mat._(p);
}