code: function() {
      var rad = this.config.radius;
      if (rad !== "auto") { return rad; }
      var s = this.canvas.getSize();
      return Math.min(s.width, s.height) / 2;
    }
docs: /*
  Method: getRadius
  
  Returns the current radius of the visualization. If *config.radius* is *auto* then it
  calculates the radius by taking the smaller size of the <Canvas> widget.
  
  See also:
  
  <Canvas.getSize>