title: OpenCV change RGB parameters in rectangle
body: <p>I have 4 points. For example...</p>
  
  <pre><code>A(1;1)
  B(2;5)
  C(4;4)
  D(3;2)
  </code></pre>
  
  <p>How I can change RGB parameters in this rectangle (for all pixels)?</p>
  
  <p>Like this:</p>
  
  <pre><code>double[] data = mat.get(x, y);
  data[0] = data[0]+30;
  data[1] = data[1]+20;
  data[2] = data[2]+10;
  mat.put(x, y, data);
  </code></pre>