title: pygtk: Draw lines onto a gtk.gdk.Pixbuf
body: <p>I'm using pygtk with PIL. I've already figured out a way to convert PIL <code>Image</code>s to <code>gtk.gdk.Pixbuf</code>s. What I do to display the pixbuf is I create a <code>gtk.gdk.Image</code>, and then use <code>img.set_from_pixbuf</code>. I now want to draw a few lines onto this image. Apparently I need a <code>Drawable</code> to do that. I've started looking through the docs but already I have 8-10 windows open and it is not being straightforward at all. </p>
  
  <p>So - what magic do I need to type to get a Drawable representing my picture, draw some things on to it, and then turn it into a <code>gdk.Image</code> so I can display it on my app?</p>