title: Extract Array of Coordinates from Line (C++ OpenCV)
body: <p>Using C++ / OpenCV I've drawn a line on an image using <code>cv::line</code> and now I'm trying to extract an array of its coordinates. I've tried assigning the line to <code>cv::Mat</code> but I get an error stating I cannot convert from void to <code>cv::Mat</code>. Is there a simple way to obtain these coordinates?</p>
  
  <p>Thanks for the help!</p>