static function declareFont($name, $normal, $bold = null, $italic = null, $boldItalic = null)
    {
        self::$fonts[$name] = array(
            0 => $normal,
            StyleParser::BOLD => $bold ?: $normal,
            StyleParser::ITALIC => $italic ?: $normal,
            StyleParser::BOLD | StyleParser::ITALIC => $boldItalic ?: ($bold ?: ($italic ?: $normal))
        );
    }