/**
  * @param $colour as string, HEX colour e.g. '#00ff00'
  * @param $outline_colour as string, HEX colour e.g. '#ff0000'
  * @param $fun_factor as integer, range 0 to 10. 0,1 and 2 are pretty boring.
  * 4 to 6 is a bit fun, 7 and above is lots of fun. 
  */
 function __construct($colour, $outline_colour, $fun_factor)
 {
     $this->type = "bar_sketch";
     parent::__construct();
     $this->set_colour($colour);
     $this->set_outline_colour($outline_colour);
     $this->offset = $fun_factor;
 }
 function __construct($colour = null, $outline_colour = null)
 {
     $this->type = "bar_filled";
     parent::__construct();
     if (isset($colour)) {
         $this->set_colour($colour);
     }
     if (isset($outline_colour)) {
         $this->set_outline_colour($outline_colour);
     }
 }
 function __construct()
 {
     $this->type = "bar_stack";
     parent::__construct();
 }