title: finding "distance" between two pixel's colors
body: <p>Once more something relatively simple, but confused as to what they want.</p>
  
  <p>the method to find distance on cartesian coordinate system is 
  distance=sqrt[(x2-x1)^2 + (y2-y1)^2]</p>
  
  <p>but how do i apply it here?</p>
  
  <pre><code>    //Requires: testColor to be a valid Color
      //Effects: returns the "distance" between the current Pixel's color and  
      //         the passed color
      //         uses the standard method to calculate "distance"
      //         uses the same formula as finding distance on a
      //         Cartesian coordinate system
      double colorDistance(Color testColor) const;
  </code></pre>
  
  <p>The color class has defined colors:
  int red,green,blue</p>
  
  <p>Do i define something like 'oldGreen' 'oldRed' 'oldBlue' and get the distance that way? The passed color being red,green,blue ?</p>
  
  <p><a href="http://pastebin.com/v9K30dc7" rel="nofollow noreferrer">http://pastebin.com/v9K30dc7</a></p>