public function createFile()
    {
        $tmpfile = $this->tmpDir . '/' . $this->hash . '.tex';

        $tex = '\documentclass[12pt]{article}'."\n";
        
        $tex .= '\usepackage[utf8]{inputenc}'."\n";

        // Packages
        foreach ($this->packages as $package) {
            $tex .= '\usepackage{' . $package . "}\n";
        }
        
        $tex .= '\begin{document}'."\n";
        $tex .= '\pagestyle{empty}'."\n";
        $tex .= '\begin{displaymath}'."\n";
        
        $tex .= $this->formula."\n";
        
        $tex .= '\end{displaymath}'."\n";
        $tex .= '\end{document}'."\n";

        if (file_put_contents($tmpfile, $tex) === false) {
            throw new \Exception('Failed to open target file');
        }
    }