adjustROI method

Mat adjustROI(int dtop, int dbottom, int dleft, int dright,)

Adjusts a submatrix size and position within the parent matrix.

The method is complimentary to Mat::locateROI . The typical use of these functions is to determine the submatrix position within the parent matrix and then shift the position somehow. Typically, it can be required for filtering operations when pixels outside of the ROI should be taken into account. When all the method parameters are positive, the ROI needs to grow in all directions by the specified amount, for example:

A.adjustROI(2, 2, 2, 2);

In this example, the matrix size is increased by 4 elements in each direction. The matrix is shifted by 2 elements to the left and 2 elements up, which brings in all the necessary pixels for the filtering with the 5x5 kernel.

adjustROI forces the adjusted ROI to be inside of the parent matrix that is boundaries of the adjusted ROI are constrained by boundaries of the parent matrix. For example, if the submatrix A is located in the first row of a parent matrix and you called A.adjustROI(2, 2, 2, 2) then A will not be increased in the upward direction.

The function is used internally by the OpenCV filtering functions, like filter2D , morphological operations, and so on.

https://docs.opencv.org/4.x/d3/d63/classcv_1_1Mat.html#a9e8ea7f2a254814de7713286b6640d77

Implementation

Mat adjustROI(int dtop, int dbottom, int dleft, int dright) {
  final p = Mat.empty();
  cvRun(() => ccore.cv_Mat_adjustROI(ref, dtop, dbottom, dleft, dright, p.ptr, ffi.nullptr));
  return p;
}