title: how to change the color of a pixel in javascript
body: <p>i'm currently trying to figure out how to change the color of a black pixel into yellow. i understand that yellow has 255 green and 255 red, with 0 blue(i think).
  So i'm trying to set the Green and Red to 255 and the blue to 0 but the image continues to remain black. This is my code:</p>
  
  <pre><code>var img = new SimpleImage(200,200);
  print(img);
  
  for (var pixel of img.values()) {
      var newG = 0 - pixel.getGreen();
      var newR = 255 - pixel.getRed();
      var newB = 255 - pixel.getBlue();
      var Black = newG + newR + newB;
      pixel.setGreen(newG);
      pixel.setRed(newR);
      pixel.setBlue(newB);
  
  }
  </code></pre>
  
  <p>by the way, the class "SimpleImage" is an image of a black screen, which I am trying to turn yellow. Let me know if more info is needed, Thanks!</p>