It is refined cool-php-captcha library rehosted on GitHub.
<?php
require __DIR__.'/vendor/autoload.php';
session_start();
use CoolCaptcha\Captcha;
$captcha = new Captcha();
/** OPTIONAL configuration
$captcha->wordsFile = 'words/es.php';
$captcha->session_var = 'secretword';
$captcha->imageFormat = 'png';
$captcha->lineWidth = 3;
$captcha->scale = 3;
$captcha->blur = true;
$captcha->resourcesPath = "/var/cool-php-captcha/resources";
**/
/** OPTIONAL Simple autodetect language example
if (!empty($_SERVER['HTTP_ACCEPT_LANGUAGE'])) {
$langs = array('en', 'es');
$lang = substr($_SERVER['HTTP_ACCEPT_LANGUAGE'], 0, 2);
if (in_array($lang, $langs)) {
$captcha->wordsFile = "words/$lang.php";
}
}
**/
// Image generation
$text = $captcha->createImage();
$_SESSION['text'] = $text;
