DOMPDF only showing image watermark on the last page - php

Question

I'm trying to display an image watermark using DomPdf, but it only appears on the last page. I've looked on some sites, but I haven't found anything related.
That's my code:
<?php
require_once 'dompdf/autoload.inc.php';
//referenciar o DomPDF com namespace
use Dompdf\Dompdf;
//Referenciar o NameSpace Options
use Dompdf\Options;
//Definir Options para habilitar PHP incorporado.
$options = new Options();
$options->set('isPhpEnabled', 'true');
//Criando a Instancia
$dompdf = new Dompdf($options);
// Carrega seu HTML
$dompdf->loadhtml("<h3>https://www.TutorialsWebsite.com</h3><center><h1>Welcome to Tutorials Website</h1><div class="wpb_wrapper">
<p><strong>Tutorialswebsite</strong> is a leading online education portal that helps technologies, software, business and creative skills readers to learn new skills at their own place from the comforts of their drawing rooms. Individual, corporate and academic members have access to learn anything on tutorialswebsite.com likes video tutorials, blogs content etc.</p>
<p>From 5 years, we worked our way to adding new fresh articles on topics ranging from programming languages that helps students, leaders, IT and design professionals, project managers or anyone who is working with software development, creatives and business skills.</p>
<h2 style="text-align: center;">Mission</h2>
<p>Our mission is to deliver easy and best online resources on programming and web development to encourage our readers acquire as many skills as they would like to. We offer the useful and best tutorials for web professionals-developers, programmers, freelancer free of cost. We don’t force our readers to sign up with us or submit their details.</p>
 
</div><h2 style="font-size: 24px;text-align: center;font-family:Roboto;font-weight:700;font-style:normal" class="vc_custom_heading">About Author</h2>
<p>
<strong>Pradeep Maurya</strong> is the Professional Web Developer and Founder of “Tutorialswebsite”. He lives in Delhi and loves to be a self dependent person. As an author, he is trying his best to improve this platform day by day.
You can contact him <strong>#facebook</strong><strong>Website:</strong> https://www.pradeepmaurya.in</p></center>
'");
$dompdf->setPaper('A4', 'portrait');
//Renderizar o html
$dompdf->render();
//Instanciar o Canvas
$canvas = $dompdf->getCanvas();
//Recuperar Altura e Largura da página
$width = $canvas->get_width();
$height = $canvas->get_height();
//Especifica a Imagem de Marca D'Água
$imageURL = 'img/forper.png';
$imgHeight = 511;
$imgWidth = 250;
//Define a Opacidade da Imagem
$canvas->set_opacity(.3);
//Especifica as posições horizontal e vertical
$x = (($width - $imgWidth) / 2);
$y = (($height - $imgHeight) / 2);
//Adiciona a Imagem ao PDF
$canvas->image($imageURL, $x, $y, $imgWidth, $imgHeight);
//Exibibir a página
$dompdf->stream(
"$nip.pdf",
array(
'Attachment' => false //Para realizar o download somente alterar para true
)
);
?>
I changed the HTML because the old one was too big.
If there is only one page, the watermark will appear correctly, but if there are two or more pages, the image will only appear on the last one.
I've tried to add the code below to add the watermark in the first page, but the image is in front of the text.
// Dirty fix for images and lines
$canvas->page_script('
$image = \'img/image.png\';
// $pdf is the variable containing a reference to the canvas object provided by dompdf
$pdf->image($image, ' . $x . ', ' . $y . ', ' . $imgWidth . ', ' . $imgHeight . ');
');

Answer 1

You have to use page_script function (like you did) but you need to edit the canvas inside too.
To avoid formatting error and keeping a good syntax for maintaining, I suggest adding a new file with the canvas code only.
canvasScript.php
$canvas = $dompdf->getCanvas();
$width = $canvas->get_width();
$height = $canvas->get_height();
$imageURL = 'img/forper.png';
$imgHeight = 511;
$imgWidth = 250;
$canvas->set_opacity(.3);
$x = (($width - $imgWidth) / 2);
$y = (($height - $imgHeight) / 2);
$canvas->image($imageURL, $x, $y, $imgWidth, $imgHeight);
Your code
// [...]
// Renderize HTML
$dompdf->render();
// Add watermark to all pages
$canvasScript = file_get_contents('/canvasScript.php');
$canvas->page_script($canvasScript);
$dompdf->stream("your_pdf.pdf");
dompdf has no documentation and lack this kind of use, I recommend using mpdf/mpdf next time.