title: How to do directed graph drawing in PHP?
body: <p>I'm looking for a way to draw directed graphs in PHP. (as in <a href="http://upload.wikimedia.org/wikipedia/commons/0/08/Directed_acyclic_graph.png" rel="noreferrer">http://upload.wikimedia.org/wikipedia/commons/0/08/Directed_acyclic_graph.png</a>). I want it to create an image of the graph just like GD can output an image.</p>
  
  <p>I've googled a lot on this, but I only can find a lot of libraries for drawing graphs in general (with bars etc), not directed graphs.</p>
  
  <p>P.S. I've tried using dot (the linux program) via system(), but unfortunately I have no permission to do that on the server. Also, I have no rights to install PHP extensions and stuff like that on the server, so it should work with normal PHP (ideally just by including a file).</p>
  
  <p>Thanks in advance.</p>