Sigma.js Modularity coloration plugin. Depends on d3js for d3.scale.category20() call.

sigmajs_modularity..js

$(document).ready(function() {

  (function(){

    var Modularity = function(sig) {
      sigma.classes.Cascade.call(this);

      var self = this,
          domains = [];

      this.p = {};

      function getIndexOfDomain(domain) {
        var index = domains.indexOf(domain);
        if(index == -1) {
          index = domains.length;
          domains.push(domain);
        }
        return index;
      }

      function getAttributeIndex(node, attr) {
        for ( var i = node.attr.attributes.length - 1; i > -1; i--) {
          if(node.attr.attributes[i].attr == attr)
            return i
        }
      }
      function getAttributeValue(node, attr) {
        var attrIndex = getAttributeIndex(node, attr);
        return node['attr']['attributes'][attrIndex]['val'];
      }

      this.computeModularity = function() {
        var colors = d3.scale.category20();

        sig.graph.nodes.forEach(function(node) {
          var category = getAttributeValue(node, 'topic'),
              index = getIndexOfDomain(category);

          node.color = index < 19 ? colors(index) : colors(20);
        });
      }
    }
 
    sigma.publicPrototype.modulate = function() {
      if(!this.modularity) {
        var sigmaInstance = this;
        var mod = new Modularity(sigmaInstance._core);
        sigmaInstance.modularity = mod;
      }

      this.modularity.computeModularity();

      return this;
    }
  })()
});