I wrote this bit of code to draw block arrows on a opencv MAT

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Asked: June 13, 20262026-06-13T20:36:57+00:00 2026-06-13T20:36:57+00:00

I wrote this bit of code to draw block arrows on a opencv MAT

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I wrote this bit of code to draw block arrows on a opencv MAT image, it works but my question is, is there an easier way to rotate the image?
Is it necessary to code it in detail or is there a rotate transpose or flip method in opencv?

void Arrow( Mat img, int i ) 
    {  
  int lineType = 8;
  Point arrow_points[1][7];
if (i == 1) { //left  
  arrow_points[0][0] = Point( 90*mp, 60*mp );
  arrow_points[0][1] = Point( 90*mp, 40*mp );
  arrow_points[0][2] = Point( 50*mp, 40*mp );
  arrow_points[0][3] = Point( 50*mp, 30*mp );
  arrow_points[0][4] = Point( 10*mp, 50*mp );
  arrow_points[0][5] = Point( 50*mp, 70*mp );
  arrow_points[0][6] = Point( 50*mp, 60*mp );
};
if (i == 2) { //right 
  arrow_points[0][0] = Point( 20*mp, 60*mp );
  arrow_points[0][1] = Point( 20*mp, 40*mp );
  arrow_points[0][2] = Point( 60*mp, 40*mp );
  arrow_points[0][3] = Point( 60*mp, 30*mp );
  arrow_points[0][4] = Point( 100*mp, 50*mp );
  arrow_points[0][5] = Point( 60*mp, 70*mp );
  arrow_points[0][6] = Point( 60*mp, 60*mp );
};
if (i == 3) { //down
  arrow_points[0][0] = Point( 60*mp, 20*mp );
  arrow_points[0][1] = Point( 40*mp, 20*mp );
  arrow_points[0][2] = Point( 40*mp, 60*mp );
  arrow_points[0][3] = Point( 30*mp, 60*mp );
  arrow_points[0][4] = Point( 50*mp, 100*mp );
  arrow_points[0][5] = Point( 70*mp, 60*mp );
  arrow_points[0][6] = Point( 60*mp, 60*mp );
};
  const Point* ppt[1] = { arrow_points[0] };
  int npt[] = { 7 };
  fillPoly( img,
        ppt,
        npt,
           1,
      Scalar( 250, 0, 0 ),
    lineType );
}