code: function(npos, pos, width, height){
        // TODO(nico): be more precise...
        width /= 2; 
        height /= 2;
        var dist = (width + height) / 2, 
            diffx = npos.x - pos.x, 
            diffy = npos.y - pos.y, 
            diff = diffx * diffx + diffy * diffy;
        return diff <= dist * dist;
      }
docs: /*
  Method: contains
  
  Returns *true* if *pos* is contained in the area of the shape. Returns *false* otherwise.
  
  Parameters:
  
  npos - (object) An *x*, *y* object with the <Graph.Node> position.
  pos - (object) An *x*, *y* object with the position to check.
  width - (number) The width of the rendered ellipse.
  height - (number) The height of the rendered ellipse.
  
  Example:
  (start code js)
  NodeHelper.ellipse.contains({ x: 10, y: 30 }, { x: 15, y: 35 }, 30, 40);
  (end code)