--- /dev/null
+<?PHP // $Id$
+ // 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
+
+ $nomoodlecookie = true; // Because it interferes with caching
+
+ require_once("../../config.php");
+
+
+ $CFG->texfilterdir = "filter/tex";
+ $CFG->teximagedir = "filter/tex";
+
+ error_reporting(E_ALL);
+ $query = urldecode($_SERVER['QUERY_STRING']);
+
+ if ($query) {
+ $output = $query;
+ $splitpos = strpos($query,'&')-4;
+ $texexp = substr($query,4,$splitpos);
+ $md5 = md5($texexp);
+ if (strpos($query,'ShowDB') || strpos($query,'DeleteDB')) {
+ $texcache = get_record("cache_filters","filter","tex", "md5key", $md5);
+ }
+ if (strpos($query,'ShowDB')) {
+ if ($texcache) {
+ $output = "DB cache_filters entry for $texexp\n";
+ $output .= "id = $texcache->id\n";
+ $output .= "filter = $texcache->filter\n";
+ $output .= "version = $texcache->version\n";
+ $output .= "md5key = $texcache->md5key\n";
+ $output .= "rawtext = $texcache->rawtext\n";
+ $output .= "timemodified = $texcache->timemodified\n";
+ } else {
+ $output = "DB cache_filters entry for $texexp not found\n";
+ }
+ }
+ if (strpos($query,'DeleteDB')) {
+ if ($texcache) {
+ $output = "Deleting DB cache_filters entry for $texexp\n";
+ $result = delete_records("cache_filters","id",$texcache->id);
+ if ($result) {
+ $result = 1;
+ } else {
+ $result = 0;
+ }
+ $output .= "Number of records deleted = $result\n";
+ } else {
+ $output = "Could not delete DB cache_filters entry for $texexp\nbecause it could not be found.\n";
+ }
+ }
+ if (strpos($query,'ShowImage')) {
+ tex2image($texexp);
+ } else {
+ outputText($output);
+ }
+ exit;
+ }
+
+
+function outputText($texexp) {
+ header("Content-type: text/html");
+ echo "<html><body><pre>\n";
+ if ($texexp) {
+ $texexp = str_replace('<','<',$texexp);
+ $texexp = str_replace('>','>',$texexp);
+ $texexp = str_replace('"','"',$texexp);
+ echo "$texexp\n\n";
+ } else {
+ echo "No text output available\n\n";
+ }
+ echo "</pre></body></html>\n";
+}
+
+function tex2image($texexp) {
+ global $CFG;
+ if ($texexp) {
+ $texexp = '\Large ' . $texexp;
+ $lifetime = 86400;
+ $image = md5($texexp) . ".gif";
+ $filetype = 'image/gif';
+ if (!file_exists("$CFG->dataroot/$CFG->teximagedir")) {
+ make_upload_directory($CFG->teximagedir);
+ }
+ $pathname = "$CFG->dataroot/$CFG->teximagedir/$image";
+ $windows = 0;
+ switch (PHP_OS) {
+ case "Linux":
+ $cmd = "$CFG->dirroot/$CFG->texfilterdir/mimetex.linux -e $pathname ". escapeshellarg($texexp);
+ break;
+ case "WINNT":
+ case "WIN32":
+ case "Windows":
+ $windows = 1;
+ $texexp = str_replace('"','\"',$texexp);
+ $cmd = "$CFG->dirroot/$CFG->texfilterdir/mimetex.exe -e $pathname \"$texexp\"";
+ break;
+ case "Darwin":
+ $cmd = "$CFG->dirroot/$CFG->texfilterdir/mimetex.darwin -e $pathname ". escapeshellarg($texexp);
+ break;
+ }
+ system($cmd);
+ }
+ if ($texexp && file_exists($pathname)) {
+ $lastmodified = filemtime($pathname);
+ header("Last-Modified: " . gmdate("D, d M Y H:i:s", $lastmodified) . " GMT");
+ header("Expires: " . gmdate("D, d M Y H:i:s", time() + $lifetime) . " GMT");
+ header("Cache-control: max_age = $lifetime"); // a day
+ header("Pragma: ");
+ header("Content-disposition: inline; filename=$image");
+ header("Content-length: ".filesize($pathname));
+ header("Content-type: $filetype");
+ readfile("$pathname");
+ } else {
+ if (!$windows) {
+ $cmd = "$cmd 2>&1";
+ echo `$cmd` . "<br>\n";
+ }
+ echo "Image not found!";
+ }
+}
+?>
+
+<html>
+<head><title>TeX Filter Debugger</title></head>
+<body>
+<?PHP
+ require_once("../../config.php");
+ $filename = "$CFG->dirroot/filter/tex/pix.php";
+ $PHP_OS = PHP_OS;
+ $handle = fopen($filename,"r");
+ $contents = fread($handle, filesize($filename));
+ fclose($handle);
+ if (!strpos($contents,'case "'. $PHP_OS . '":')) {
+ echo "<b>WARNING!</b> case \"$PHP_OS\": NOT found in pix.php!!!<br><br>";
+ }
+?>
+ <p>Please enter an algebraic expression <b>without</b> any surrounding $$ into
+ the text box below. (Click <a href="#help">here for help.</a>)
+ <form action="texdebug.php" method="get"
+ target="inlineframe">
+ <center>
+ <input type="text" name="tex" size=50
+ value="\Large f(x)=\Bigint_{-\infty}^x~e^{-t^2}dt">
+ </center>
+ <ol>
+ <li>First click on this button <input type="submit" name="ShowDB" value="Show DB Entry">
+ to see the cache_filters database entry for this expression.</li>
+ <li>If the database entry looks corrupt, click on this button to delete it:
+ <input type="submit" name="DeleteDB" value="Delete DB Entry"></li>
+ <li>Finally click on this button <input type="submit" name="ShowImage" value="Show Image">
+ to show a graphic image of the algebraic expression.</li>
+ </ol>
+ </form> <br> <br>
+ <center>
+ <iframe name="inlineframe" align="middle" width="80%" height="200">
+ <p>Something is wrong...</p>
+ </iframe>
+ </center> <br>
+<hr>
+<a name="help">
+<h2>Debugging Help</h2>
+</a>
+<p>First a brief overview of how the TeX filter works. The TeX filter first
+searches the database cache_filters table to see if this TeX expression had been
+processed before. If not, it adds a DB entry for that expression. It then
+replaces the TeX expression by an <img src=".../filter/tex/pix.php...">
+tag. The filter/tex/pix.php script then searches the database to find an
+appropriate gif image file for that expression and to create one if it doesn't exist.
+Here are a few common things that can go wrong and some suggestions on how
+you might try to fix them.</p>
+<ol>
+<li>Something had gone wrong on a previous occasion when the filter tried to
+process this expression. Then the database entry for that expression contains
+a bad TeX expression in the rawtext field (usually blank). You can fix this
+by clicking on "Delete DB Entry"</li>
+<li>The TeX to gif image conversion process does not work. If your server is
+running Unix, a likely cause is that the mimetex binary you are using is
+incompatible with your operating system. You can try compiling it from the
+C sources downloaded from <a href="http://www.forkosh.com/mimetex.zip">
+http://www.forkosh.com/mimetex.zip</a>, or looking for an appropriate
+binary at <a href="http://moodle.org/download/mimetex/">
+http://moodle.org/download/mimetex/</a>. You may then also need to
+edit your moodle/filter/tex/pix.php file to add
+<br /><?PHP echo "case "" . PHP_OS . "":" ;?><br ?> to the list of operating systems
+in the switch (PHP_OS) statement. Windows users may have a problem properly
+unzipping mimetex.exe. Make sure that mimetex.exe is is <b>PRECISELY</b>
+328192 bytes in size. If not, download a fresh copy from
+<a href="http://moodle.org/download/mimetex/windows/mimetex.exe">
+http://moodle.org/download/mimetex/windows/mimetex.exe</a>.
+Another possible problem which may affect
+both Unix and Windows servers is that the web server doesn't have execute permission
+on the mimetex binary. In that case change permissions accordingly</li>
+</ol>
+</body>
+</html>
projects / moodle.git / commitdiff