private function __construct() {
$this->fonts ['Arial'] = array ('stack' => 'Arial,\'Helvetica\',sans-serif' );
$this->fonts ['Calibri'] = array ('stack' => 'Calibri,Candara,\'Segoe\',\'Segoe UI\',Optima,Arial,sans-serif' );
$this->fonts ['Cambria'] = array ('stack' => 'Cambria,Georgia,serif' );
$this->fonts ['Corbel'] = array ('stack' => 'Corbel,\'Lucida Grande\',\'Lucida Sans Unicode\',\'Lucida Sans\',Verdana,sans-serif' );
$this->fonts ['Courier New'] = array ('stack' => '\'Courier New\',Courier,monospace' );
$this->fonts ['Georgia'] = array ('stack' => 'Georgia,Times,\'Times New Roman\',serif' );
$this->fonts ['Lato'] = array ('stack' => 'Lato,Verdana,Helvetica,sans-serif', 'style' => 'lato' );
$this->fonts ['Open Sans'] = array ('stack' => '\'Open Sans\',Verdana,Helvetica,sans-serif', 'style' => 'opensans' );
$this->fonts ['Tahoma'] = array ('stack' => 'Tahoma,Verdana,Segoe,sans-serif' );
$this->fonts ['Times New Roman'] = array ('stack' => '\'Times New Roman\',Times,Georgia,serif' );
$this->fonts ['Trebuchet MS'] = array ('stack' => '\'Trebuchet MS\',\'Lucida Grande\',\'Lucida Sans Unicode\',\'Lucida Sans\',Tahoma,sans-serif' );
$this->fonts ['Verdana'] = array ('stack' => 'Verdana,Geneva,sans-serif' );
$this->fonts ['Dosis'] = array ('stack' => 'Dosis,Verdana,Helvetica,sans-serif', 'style' => 'dosis' );
$this->fonts ['Raleway'] = array ('stack' => 'Raleway,Verdana,Helvetica,sans-serif', 'style' => 'raleway' );
$this->fonts ['Roboto Slab'] = array ('stack' => '\'Roboto Slab\',Verdana,Helvetica,sans-serif', 'style' => 'robotoslab' );
$this->fonts ['Arvo'] = array ('stack' => 'Arvo,Verdana,Helvetica,sans-serif', 'style' => 'arvo' );
$this->fonts ['Fjalla One'] = array ('stack' => '\'Fjalla One\',Verdana,Helvetica,sans-serif', 'style' => 'fjallaone' );
$this->fonts ['Archivo Black'] = array ('stack' => '\'Archivo Black\',Verdana,Helvetica,sans-serif', 'style' => 'archivoblack' );
$this->fonts ['Lobster'] = array ('stack' => 'Lobster,Verdana,Helvetica,sans-serif', 'style' => 'lobster' );
$this->fonts ['Source Sans Pro'] = array ('stack' => '\'Source Sans Pro\',Verdana,Helvetica,sans-serif', 'style' => 'sourcesanspro' );
$this->fonts ['PT Sans'] = array ('stack' => '\'PT Sans\',Tahoma,Helvetica,sans-serif', 'style' => 'ptsans' );
$this->fonts ['Roboto'] = array ('stack' => 'Roboto,Tahoma,Helvetica,sans-serif', 'style' => 'roboto' );
$this->fonts ['Signika'] = array ('stack' => 'Signika,Tahoma,Helvetica,sans-serif', 'style' => 'signika' );
}