How to convert HTML pages into images using PHP

In web development, it is often necessary to convert HTML pages into images for functions such as generating verification codes and email screenshots. As a very popular server scripting language, PHP can also convert HTML to images. This article will explain how to use PHP to convert HTML pages into images.

1. Understand the principle of converting HTML to pictures

Before introducing the specific implementation, let’s briefly understand the principle of converting HTML to pictures. A common way is to use a third-party library to render the HTML page into an image, and then output the image to the browser or save it as a file.

2. Install necessary extensions

PHP does not natively support converting HTML into images and needs to rely on third-party extensions. Among the more popular ones are wkhtmltoimage, dompdf, phantomjs, etc.

Taking wkhtmltoimage as an example, you need to install the wkhtmltox library on the server first.

sudo apt-get update
sudo apt-get install wkhtmltopdf

Then install the PHP extension php-wkhtmltox.

sudo apt-get install php-wkhtmltox

3. Use wkhtmltoimage extension

After installing the wkhtmltoimage extension, you can use the following code to convert the HTML page into pictures.

<?php
$command = &#39;wkhtmltoimage http://www.baidu.com ./baidu.jpg&#39;;
$result = shell_exec($command);

In the above code, the wkhtmltoimage command renders the http://www.baidu.com page into an image and saves it as ./baidu. jpg file.

In addition to converting images from web addresses, you can also convert local HTML files into images:

<?php
$command = &#39;wkhtmltoimage ./local.html ./local.jpg&#39;;
$result = shell_exec($command);

4. Use dompdf extension

dompdf is a PHP extension that converts HTML to PDF. It can also convert HTML to images.

Install the dompdf extension.

composer require dompdf/dompdf

Use the following code to convert HTML pages into images.

<?php
use Dompdf\Dompdf;

$html = file_get_contents(&#39;http://www.baidu.com&#39;);
$dompdf = new Dompdf();
$dompdf->loadHtml($html);
$dompdf->render();
$file = './baidu.png';
file_put_contents($file, $dompdf->output());

In the above code, use file_get_contents to get the page HTML content, and then use Dompdf to render it into an image on the server side and save it locally.

5. Use phantomjs Extension

Similar to dompdf, phantomjs is also a tool that can convert HTML pages into Tools for rendering into images. Install the phantomjs library.

sudo apt-get install phantomjs

Then use the following code to convert the HTML page into an image.

<?php
$html = file_get_contents('http://www.baidu.com');
$command = 'phantomjs rasterize.js ' . escapeshellarg($html) . ' ./baidu.png 800px*600px';
$result = shell_exec($command);

In the above code, the phantomjs command uses the rasterize.js script to complete page rendering. Among them, the first parameter is the HTML content to be rendered, the second parameter is the output file, and the third parameter is the size of the output image.

6. Summary

This article describes how to use PHP to convert HTML pages into images. We can use extensions such as wkhtmltoimage, dompdf or phantomjs to achieve this functionality. When using different extensions, you also need to pay attention to the installation of its dependent environment and the use of related libraries.

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