MPDF格局不起作用

I am using MPDF in codeigniter but it is always portrait..

Why is it always portrait ?

public function downloadstatisticsWeek1()
    {
        $data = [];
        $html = $this->load->view('pdf/weeklyKeyIndicatorReportWeek1', $data, true);
        $pdfFilePath = "Pcdom Statistics As of ". date('F d Y')." .pdf";
        $this->load->library('pcdom_pdf_converter');

        $

        $param = '"en-GB-x","Letter-L","","",10,10,10,10,6,3';

        $pdfer = new mPDF($param);
        $pdfer->WriteHTML($html);
        $pdfer->output($pdfFilePath, "D");
    }

It my $para is incorrect?

Try to remove $param, see following:

//$param = '"en-GB-x","Letter-L","","",10,10,10,10,6,3';

$pdfer = new mPDF("en-GB-x","Letter-L","","",10,10,10,10,6,3);

Your code problem: you are passing one string into mPDF(), the string which is not valid.

If you would like to re-use the param, you could try following version (But I did not tested, ps: it for mPDF version 7), detail please refer this documentation.

$param = array(
    'mode' => 'en-GB-x',
    'format' => 'Letter-L',
    'margin_left' => 10,
    'margin_right' => 10,
    'margin_top' => 10,
    'margin_bottom' => 10,
    'margin_header' => 6,
    'margin_footer' => 3
);

Finally, you may also consider this function AddPage() too.