code: function getBoundaries(graph, config, level, orn, prop) {
      var dim = config.Node;
      var multitree = config.multitree;
      if (dim.overridable) {
        var w = -1, h = -1;
        graph.eachNode(function(n) {
          if (n._depth == level
              && (!multitree || ('$orn' in n.data) && n.data.$orn == orn)) {
            var dw = n.getData('width', prop);
            var dh = n.getData('height', prop);
            w = (w < dw) ? dw : w;
            h = (h < dh) ? dh : h;
          }
        });
        return {
          'width' : w < 0 ? dim.width : w,
          'height' : h < 0 ? dim.height : h
        };
      } else {
        return dim;
      }
    }
docs: /*
  Calculates the max width and height nodes for a tree level