/**
  * Get a global font characteristic
  * @param $key
  * @returns mixed  the value associated to the $key
  */
 public function getFontCharacteristic($key)
 {
     if ($this->direction != -1) {
         return $this->font_metrics[$this->direction]->getFontCharacteristic($key);
     } else {
         return parent::getFontCharacteristic($key);
     }
 }