public function allFonts(PHPExcel $pPHPExcel = null)
    {
        // Get an array of unique fonts
        $aFonts = array();
        $aStyles = $this->allStyles($pPHPExcel);

        foreach ($aStyles as $style) {
            if (!array_key_exists($style->getFont()->getHashCode(), $aFonts)) {
                $aFonts[ $style->getFont()->getHashCode() ] = $style->getFont();
            }
        }

        return $aFonts;
    }