code: function(tag, node, controller) {
        var pos = node.pos.clone(), 
            canvas = this.viz.canvas,
            height = node.getData('height'),
            ldist = ((height || node._depth == 0)? height : this.viz.config.levelDistance) /2,
            radius = canvas.getSize();
        pos.rho += ldist;
        pos = pos.getc(true);
        
        var labelPos = {
          x: Math.round(pos.x + radius.width / 2),
          y: Math.round(pos.y + radius.height / 2)
        };
  
        var style = tag.style;
        style.left = labelPos.x + 'px';
        style.top = labelPos.y + 'px';
        style.display = this.fitsInCanvas(labelPos, canvas) ? '' : 'none';
  
        controller.onPlaceLabel(tag, node);
      }
docs: /*
  placeLabel
  
  Overrides abstract method placeLabel in <Graph.Plot>.
  
  Parameters:
  
  tag - A DOM label element.
  node - A <Graph.Node>.
  controller - A configuration/controller object passed to the visualization.