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See Release Notes
Long Term Support Release

  • Bug fixes for general core bugs in 4.1.x will end 13 November 2023 (12 months).
  • Bug fixes for security issues in 4.1.x will end 10 November 2025 (36 months).
  • PHP version: minimum PHP 7.4.0 Note: minimum PHP version has increased since Moodle 4.0. PHP 8.0.x is supported too.
/filter/tex/ -> pix.php (source)
<?php
      // This function fetches math. images from the data directory
      // If not, it obtains the corresponding TeX expression from the cache_tex db table
      // and uses mimeTeX to create the image file

// disable moodle specific debug messages and any errors in output
define('NO_DEBUG_DISPLAY', true);
define('NO_MOODLE_COOKIES', true); // Because it interferes with caching

    require_once('../../config.php');

    if (!filter_is_enabled('tex')) {
        throw new \moodle_exception('filternotenabled');
    }

    require_once($CFG->libdir.'/filelib.php');
    require_once($CFG->dirroot.'/filter/tex/lib.php');
    require_once($CFG->dirroot.'/filter/tex/latex.php');

    $cmd    = '';               // Initialise these variables
    $status = '';

    $relativepath = get_file_argument();

    $args = explode('/', trim($relativepath, '/'));

    if (count($args) == 1) {
        $image    = $args[0];
        $pathname = $CFG->dataroot.'/filter/tex/'.$image;
    } else {
        throw new \moodle_exception('invalidarguments', 'error');
    }

    if (!file_exists($pathname)) {
        $convertformat = get_config('filter_tex', 'convertformat');
        if (strpos($image, '.png')) {
            $convertformat = 'png';
        }
        $md5 = str_replace(".{$convertformat}", '', $image);
        if ($texcache = $DB->get_record('cache_filters', array('filter'=>'tex', 'md5key'=>$md5))) {
            if (!file_exists($CFG->dataroot.'/filter/tex')) {
                make_upload_directory('filter/tex');
            }

            // try and render with latex first
            $latex = new latex();
            $density = get_config('filter_tex', 'density');
            $background = get_config('filter_tex', 'latexbackground');
            $texexp = $texcache->rawtext; // the entities are now decoded before inserting to DB
            $lateximage = $latex->render($texexp, $image, 12, $density, $background);
            if ($lateximage) {
                copy($lateximage, $pathname);
            } else {
                // failing that, use mimetex
                $texexp = $texcache->rawtext;
                $texexp = str_replace('&lt;', '<', $texexp);
                $texexp = str_replace('&gt;', '>', $texexp);
                $texexp = preg_replace('!\r\n?!', ' ', $texexp);
                $texexp = '\Large '.$texexp;
                $cmd = filter_tex_get_cmd($pathname, $texexp);
                system($cmd, $status);
            }
        }
    }

    if (file_exists($pathname)) {
< send_file($pathname, $image);
> send_file($pathname, $image, YEARSECS, 0, false, false, '', false, [ > 'cacheability' => 'public', > 'immutable' => true, > ]);
} else { if (debugging()) { echo "The shell command<br />$cmd<br />returned status = $status<br />\n"; echo "Image not found!<br />"; echo "Please try the <a href=\"$CFG->wwwroot/filter/tex/texdebug.php\">debugging script</a>"; } else { echo "Image not found!<br />"; echo "Please try the <a href=\"$CFG->wwwroot/filter/tex/texdebug.php\">debugging script</a><br />"; echo "Please turn on debug mode in site configuration to see more info here."; } }