php - fpdi with tcpdf new added text not showing in the pdf

enter image description hereI am trying to adding text in existing pdf using fpdi with tcpdf library. but text are not showing on the pdf. if i search pdf text can be highlighted but it is hidden on pdf. i have tried z-index too but still not appear.

please see below is my code.

$pdf = new FPDI();
$pageCount = $pdf->setSourceFile('102215_2019_unlocked.pdf');
for ($pageNo = 1; $pageNo <= $pageCount; $pageNo++) {
// import a page
$templateId = $pdf->importPage($pageNo);
// get the size of the imported page
$size = $pdf->getTemplateSize($templateId);
//$pdf->setPrintHeader(false);


// create a page (landscape or portrait depending on the imported page size)
if ($size['w'] > $size['h']) {
$pdf->AddPage('L', array($size['w'], $size['h']));
// Font size 1/3 Height if it landscape
$fontsize = $size['h'] / 3;
} else {
$pdf->AddPage('P', array($size['w'], $size['h']));

// Font size 1/3 Width if it portrait
$fontsize = $size['w'] / 3;
}

$html = '<h1 style="z-index:-1;color:black;">[![HTML Example][1]][1]</h1>';

// output the HTML content
$pdf->writeHTML($html, true, false, true, false, '');

$pdf->useTemplate($templateId);

// $pdf->SetAlpha(1);
}

$pdf->output();

Answer

Solution:

ok i have found answer myself finally.

usetemplate function was needed to put before the text and my image applied.

like this

$pdf->useTemplate($templateId);

$pdf->StartTransform();

$pdf->Image('logo.png', 175, 5, 35, 0, 'PNG','https://franchimp.com');

$pdf->SetFont('Helvetica', 'B', 70);
$pdf->SetTextColor(31, 156, 239);
$pdf->SetAlpha(0.5);  
$pdf->SetXY(20, 180);
$pdf->Rotate(35);
$pdf->Write(0, 'franchimp.com');
$pdf->StopTransform();

Source