title: Best way to visualize a graph and voronoi diagram in c++
body: <p>I am writing a program to compute the k-means clustering of a pointset.  I want to visualize the steps, so to save a picture of each step in jpg or png form.  It would also be nice to save a picture of the Voronoi diagram at the end, as well.</p>
  
  <p>What is the best tool for drawing and saving an image of a graph, given the edges and vertices?  Coloured vertices would be a plus</p>