/**
  * Set whether or not this is a fixed width font
  * @parma boolean $is_fixed_width
  */
 public function setFixedWidth($is_fixed_width)
 {
     if ($this->direction == -1) {
         foreach ($this->directions as $direction) {
             $this->font_metrics[$direction]->setFixedWidth($is_fixed_width);
         }
         parent::setFixedWidth($is_fixed_width);
     } else {
         $this->font_metrics[$this->direction]->setFixedWidth($is_fixed_width);
     }
 }