title: OpenCV: Mat::reshape() does nothing
body: <p>I have a <code>640 x 480 CV_8UC3</code> <code>Mat image</code> and want to perform the k-means segmentation. So I need to convert it to <code>CV_32F</code> (no problem here), reshape it, and run k-means.</p>
  
  <p>The problem is <code>reshape()</code> does nothing:</p>
  
  <pre><code>cv::Mat colorMat;
  image.convertTo (colorMat, CV_32FC3);
  std::cout &lt;&lt; colorMat.size () &lt;&lt; "; ch: " &lt;&lt; colorMat.channels () &lt;&lt; std::endl; // [640 x 480]; ch: 3
  colorMat.reshape (1, colorMat.rows * colorMat.cols); // Here I expect it to become [307200 x 3], 1 channel - each column representing a color component
  std::cout &lt;&lt; colorMat.size () &lt;&lt; "; ch: " &lt;&lt; colorMat.channels () &lt;&lt; std::endl; // [640 x 480]; ch: 3
  </code></pre>
  
  <p>Am I doing something wrong?</p>