title: Drawing diagonal lines on an image
body: <p>Hi im trying to draw diagonal lines across an image top right to bottom left here is my code so far.</p>
  
  <pre><code>  width = getWidth(picture)
    height = getHeight(picture)
    for x in range(0, width):
      for y in range(0, height):
        pixel = getPixel(picture, x, y)
        setColor(pixel, black)
  </code></pre>
  
  <p>Thanks</p>