filter/tex/pix.php

   1 <?php
   2       // This function fetches math. images from the data directory
   3       // If not, it obtains the corresponding TeX expression from the cache_tex db table
   4       // and uses mimeTeX to create the image file
   5
   6 // disable moodle specific debug messages and any errors in output
   7 define('NO_DEBUG_DISPLAY', true);
   8 define('NO_MOODLE_COOKIES', true); // Because it interferes with caching
   9
  10     require_once('../../config.php');
  11
  12     if (!filter_is_enabled('tex')) {
  13         throw new \moodle_exception('filternotenabled');
  14     }
  15
  16     require_once($CFG->libdir.'/filelib.php');
  17     require_once($CFG->dirroot.'/filter/tex/lib.php');
  18     require_once($CFG->dirroot.'/filter/tex/latex.php');
  19
  20     $cmd    = '';               // Initialise these variables
  21     $status = '';
  22
  23     $relativepath = get_file_argument();
  24
  25     $args = explode('/', trim($relativepath, '/'));
  26
  27     if (count($args) == 1) {
  28         $image    = $args[0];
  29         $pathname = $CFG->dataroot.'/filter/tex/'.$image;
  30     } else {
  31         throw new \moodle_exception('invalidarguments', 'error');
  32     }
  33
  34     if (!file_exists($pathname)) {
  35         $convertformat = get_config('filter_tex', 'convertformat');
  36         if (strpos($image, '.png')) {
  37             $convertformat = 'png';
  38         }
  39         $md5 = str_replace(".{$convertformat}", '', $image);
  40         if ($texcache = $DB->get_record('cache_filters', array('filter'=>'tex', 'md5key'=>$md5))) {
  41             if (!file_exists($CFG->dataroot.'/filter/tex')) {
  42                 make_upload_directory('filter/tex');
  43             }
  44
  45             // try and render with latex first
  46             $latex = new latex();
  47             $density = get_config('filter_tex', 'density');
  48             $background = get_config('filter_tex', 'latexbackground');
  49             $texexp = $texcache->rawtext; // the entities are now decoded before inserting to DB
  50             $lateximage = $latex->render($texexp, $image, 12, $density, $background);
  51             if ($lateximage) {
  52                 copy($lateximage, $pathname);
  53             } else {
  54                 // failing that, use mimetex
  55                 $texexp = $texcache->rawtext;
  56                 $texexp = str_replace('&lt;', '<', $texexp);
  57                 $texexp = str_replace('&gt;', '>', $texexp);
  58                 $texexp = preg_replace('!\r\n?!', ' ', $texexp);
  59                 $texexp = '\Large '.$texexp;
  60                 $cmd = filter_tex_get_cmd($pathname, $texexp);
  61                 system($cmd, $status);
  62             }
  63         }
  64     }
  65
  66     if (file_exists($pathname)) {
  67         send_file($pathname, $image, YEARSECS, 0, false, false, '', false, [
  68             'cacheability' => 'public',
  69             'immutable' => true,
  70         ]);
  71     } else {
  72         if (debugging()) {
  73             echo "The shell command<br />$cmd<br />returned status = $status<br />\n";
  74             echo "Image not found!<br />";
  75             echo "Please try the <a href=\"$CFG->wwwroot/filter/tex/texdebug.php\">debugging script</a>";
  76         } else {
  77             echo "Image not found!<br />";
  78             echo "Please try the <a href=\"$CFG->wwwroot/filter/tex/texdebug.php\">debugging script</a><br />";
  79             echo "Please turn on debug mode in site configuration to see more info here.";
  80         }
  81     }