title: OpenCV. How do I multiply point and matrix (CvMat)
body: <p>I have matrix that is used for rotation:</p>
  
  <pre><code>CvMat* rot_mat = cvCreateMat(2, 3, CV_32FC1);
  cv2DRotationMatrix(center, angle, scale, rot_mat);
  ...
  </code></pre>
  
  <p>This matrix is used for image operations. </p>
  
  <pre><code>cvWarpAffine(..., ..., rot_mat, ..., ...);
  </code></pre>
  
  <p>I have to know, how this matrix should affect exact pixel - location it should be transfered. </p>
  
  <p>How can I multiply 2D point (pixel location) and my matrix to find out where pixel should be transferred? </p>