code: function(pt, cos, sin, c)
  	{
  		c = (c != null) ? c : new mxPoint();
  		var x = pt.x - c.x;
  		var y = pt.y - c.y;
  
  		var x1 = x * cos - y * sin;
  		var y1 = y * cos + x * sin;
  
  		return new mxPoint(x1 + c.x, y1 + c.y);
  	}
docs: Function: getRotatedPoint
  
  Rotates the given point by the given cos and sin.