title: A simple algorithm for polygon intersection
body: <p>I'm looking for a very simple algorithm for computing the polygon intersection/clipping.
  That is, given polygons <code>P</code>, <code>Q</code>, I wish to find polygon <code>T</code> which is contained in <code>P</code> and in <code>Q</code>, and I wish <code>T</code> to be maximal among all possible polygons.</p>
  
  <p>I don't mind the run time (I have a few very small polygons), I can also afford getting an approximation of the polygons' intersection (that is, a polygon with less points, but which is still contained in the polygons' intersection).</p>
  
  <p>But it is really important for me that the algorithm will be simple (cheaper testing) and preferably short (less code).</p>
  
  <p><strong>edit:</strong> please note, I wish to obtain a polygon which represent the intersection. I don't need only a boolean answer to the question of whether the two polygons intersect.</p>