title: Open Source Graph Drawing program supporting Planar graph testing?
body: <p>In graph theory, a planar graph is a graph that can be embedded in the plane, i.e., it can be drawn on the plane in such a way that its edges intersect only at their endpoints.</p>
  
  <p>Their are many algorithms which exist for planar graph testing (i.e. determining if a given graph is Planar). The best ones are in O(n) where n is the number of vertices.</p>
  
  <p>Which open source programs exist which support the following features:</p>
  
  <ul>
  <li>Can Draw Planar Graphs</li>
  <li>Support an O(n) Planar graph testing.</li>
  <li>Support variable node size.</li>
  <li>Support fixed drawing boundary region</li>
  <li>Are open source</li>
  </ul>