private function setTcpdfConstants()
    {
        foreach ($this->config_constant_map as $const => $configkey)
        {
            if (!defined($const))
            {
                if (is_string(\Config::get('laravel-tcpdf::' . $configkey)))
                {
                    if (strlen(\Config::get('laravel-tcpdf::' . $configkey)) > 0)
                    {
                        define($const, \Config::get('laravel-tcpdf::' . $configkey));
                    }
                }
                else
                {
                    define($const, \Config::get('laravel-tcpdf::' . $configkey));
                }
            }
        }
    }