Pop\Pdf\Pdf::setStyle PHP Method

    protected function setStyle($fill)
    {
        $style = null;
        if ($fill && $this->stroke) {
            $style = 'B';
        } else {
            if ($fill) {
                $style = 'F';
            } else {
                $style = 'S';
            }
        }
        return $style;
    }