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387 lines
16 KiB
387 lines
16 KiB
2 years ago
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<?php
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// This file is part of Moodle - http://moodle.org/
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//
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// Moodle is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// Moodle is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
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/**
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* This function fetches math. images from the data directory
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* If not, it obtains the corresponding TeX expression from the cache_tex db table
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* and uses mimeTeX to create the image file
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*
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* @package filter
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* @subpackage tex
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* @copyright 2004 Zbigniew Fiedorowicz fiedorow@math.ohio-state.edu
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* Originally based on code provided by Bruno Vernier bruno@vsbeducation.ca
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* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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*/
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require_once("../../config.php");
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if (!filter_is_enabled('tex')) {
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print_error('filternotenabled');
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}
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require_once($CFG->libdir.'/filelib.php');
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require_once($CFG->dirroot.'/filter/tex/lib.php');
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require_once($CFG->dirroot.'/filter/tex/latex.php');
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$action = optional_param('action', '', PARAM_ALPHA);
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$texexp = optional_param('tex', '', PARAM_RAW);
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require_login();
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require_capability('moodle/site:config', context_system::instance(), $USER->id); /// Required cap to run this. MDL-18552
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if ($action || $texexp) {
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require_sesskey();
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}
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$output = '';
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// look up in cache if required
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if ($action=='ShowDB' or $action=='DeleteDB') {
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$md5 = md5($texexp);
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$texcache = $DB->get_record("cache_filters", array("filter"=>"tex", "md5key"=>$md5));
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}
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// Action: Show DB Entry
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if ($action=='ShowDB') {
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if ($texcache) {
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$output = "DB cache_filters entry for $texexp\n";
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$output .= "id = $texcache->id\n";
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$output .= "filter = $texcache->filter\n";
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$output .= "version = $texcache->version\n";
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$output .= "md5key = $texcache->md5key\n";
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$output .= "rawtext = $texcache->rawtext\n";
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$output .= "timemodified = $texcache->timemodified\n";
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} else {
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$output = "DB cache_filters entry for $texexp not found\n";
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}
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}
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// Action: Delete DB Entry
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if ($action=='DeleteDB') {
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if ($texcache) {
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$output = "Deleting DB cache_filters entry for $texexp\n";
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$result = $DB->delete_records("cache_filters", array("id"=>$texcache->id));
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if ($result) {
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$result = 1;
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} else {
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$result = 0;
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}
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$output .= "Number of records deleted = $result\n";
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} else {
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$output = "Could not delete DB cache_filters entry for $texexp\nbecause it could not be found.\n";
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}
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}
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// Action: Show Image
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if ($action=='ShowImageMimetex') {
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tex2image($texexp);
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}
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// Action: Check Slasharguments
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if ($action=='SlashArguments') {
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slasharguments($texexp);
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exit;
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}
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// Action: Show Tex command line output
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if ($action=='ShowImageTex') {
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TexOutput($texexp, true);
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exit;
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}
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// Action: Show Tex command line output
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if ($action=='ShowOutputTex') {
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if (debugging()) {
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TexOutput($texexp);
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} else {
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echo "Can not output detailed information due to security concerns, please turn on debug mode first.";
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}
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exit;
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}
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if (!empty($action)) {
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outputText($output);
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}
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// nothing more to do if there was any action
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if (!empty($action)) {
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exit;
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}
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function outputText($texexp) {
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header("Content-type: text/html; charset=utf-8");
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echo "<html><body><pre>\n";
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if ($texexp) {
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echo s($texexp)."\n\n";
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} else {
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echo "No text output available\n\n";
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}
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echo "</pre></body></html>\n";
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}
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function tex2image($texexp, $return=false) {
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global $CFG;
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if (!$texexp) {
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echo 'No tex expresion specified';
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return;
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}
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$image = md5($texexp) . ".gif";
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$filetype = 'image/gif';
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if (!file_exists("$CFG->dataroot/filter/tex")) {
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make_upload_directory("filter/tex");
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}
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$pathname = "$CFG->dataroot/filter/tex/$image";
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if (file_exists($pathname)) {
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unlink($pathname);
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}
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$texexp = '\Large '.$texexp;
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$commandpath = filter_tex_get_executable(true);
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$cmd = filter_tex_get_cmd($pathname, $texexp);
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system($cmd, $status);
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if ($return) {
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return $image;
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}
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if (file_exists($pathname)) {
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send_file($pathname, $image);
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} else if (debugging()) {
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$ecmd = "$cmd 2>&1";
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echo `$ecmd` . "<br />\n";
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echo "The shell command<br />$cmd<br />returned status = $status<br />\n";
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if ($status == 4) {
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echo "Status corresponds to illegal instruction<br />\n";
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} else if ($status == 11) {
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echo "Status corresponds to bus error<br />\n";
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} else if ($status == 22) {
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echo "Status corresponds to abnormal termination<br />\n";
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}
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if (file_exists($commandpath)) {
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echo "File size of mimetex executable $commandpath is " . filesize($commandpath) . "<br />";
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echo "The file permissions are: " . decoct(fileperms($commandpath)) . "<br />";
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if (function_exists("md5_file")) {
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echo "The md5 checksum of the file is " . md5_file($commandpath) . "<br />";
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} else {
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$handle = fopen($commandpath,"rb");
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$contents = fread($handle,16384);
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fclose($handle);
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echo "The md5 checksum of the first 16384 bytes is " . md5($contents) . "<br />";
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}
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} else {
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echo "mimetex executable $commandpath not found!<br />";
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}
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echo "Image not found!";
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} else {
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echo "Can not output detailed information due to security concerns, please turn on debug mode first.";
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}
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}
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// test Tex/Ghostscript output - command execution only
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function TexOutput($expression, $graphic=false) {
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global $CFG;
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$output = '';
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$latex = new latex();
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// first check if it is likely to work at all
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$output .= "<h3>Checking executables</h3>\n";
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$executablesexist = true;
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$pathlatex = trim(get_config('filter_tex', 'pathlatex'), " '\"");
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if (is_file($pathlatex)) {
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$output .= "latex executable ($pathlatex) is readable<br />\n";
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} else {
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$executablesexist = false;
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$output .= "<b>Error:</b> latex executable ($pathlatex) is not readable<br />\n";
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}
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$pathdvips = trim(get_config('filter_tex', 'pathdvips'), " '\"");
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if (is_file($pathdvips)) {
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$output .= "dvips executable ($pathdvips) is readable<br />\n";
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} else {
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$executablesexist = false;
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$output .= "<b>Error:</b> dvips executable ($pathdvips) is not readable<br />\n";
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}
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$pathconvert = trim(get_config('filter_tex', 'pathconvert'), " '\"");
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if (is_file($pathconvert)) {
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$output .= "convert executable ($pathconvert) is readable<br />\n";
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} else {
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$executablesexist = false;
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$output .= "<b>Error:</b> convert executable ($pathconvert) is not readable<br />\n";
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}
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$pathdvisvgm = trim(get_config('filter_tex', 'pathdvisvgm'), " '\"");
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if (is_file($pathdvisvgm)) {
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$output .= "dvisvgm executable ($pathdvisvgm) is readable<br />\n";
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} else {
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$executablesexist = false;
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$output .= "<b>Error:</b> dvisvgm executable ($pathdvisvgm) is not readable<br />\n";
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}
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// knowing that it might work..
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$md5 = md5($expression);
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$output .= "<p>base filename for expression is '$md5'</p>\n";
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// temporary paths
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$tex = "$latex->temp_dir/$md5.tex";
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$dvi = "$latex->temp_dir/$md5.dvi";
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$ps = "$latex->temp_dir/$md5.ps";
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$convertformat = get_config('filter_tex', 'convertformat');
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$img = "$latex->temp_dir/$md5.{$convertformat}";
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// put the expression as a file into the temp area
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$expression = html_entity_decode($expression);
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$output .= "<p>Processing TeX expression:</p><pre>$expression</pre>\n";
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$doc = $latex->construct_latex_document($expression);
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$fh = fopen($tex, 'w');
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fputs($fh, $doc);
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fclose($fh);
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// cd to temp dir
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chdir($latex->temp_dir);
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// step 1: latex command
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$pathlatex = escapeshellarg($pathlatex);
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$cmd = "$pathlatex --interaction=nonstopmode --halt-on-error $tex";
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$output .= execute($cmd);
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// step 2: dvips command
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$pathdvips = escapeshellarg($pathdvips);
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$cmd = "$pathdvips -E $dvi -o $ps";
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$output .= execute($cmd);
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// Step 3: Set convert or dvisvgm command.
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if ($convertformat == 'svg') {
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$pathdvisvgm = escapeshellarg($pathdvisvgm);
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$cmd = "$pathdvisvgm -E $ps -o $img";
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} else {
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$pathconvert = escapeshellarg($pathconvert);
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$cmd = "$pathconvert -density 240 -trim $ps $img ";
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}
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$output .= execute($cmd);
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if (!$graphic) {
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echo $output;
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} else if (file_exists($img)) {
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send_file($img, "$md5.{$convertformat}");
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} else {
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echo "Error creating image, see command execution output for more details.";
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}
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}
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function execute($cmd) {
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exec($cmd, $result, $code);
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$output = "<pre>$ $cmd\n";
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$lines = implode("\n", $result);
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$output .= "OUTPUT: $lines\n";
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$output .= "RETURN CODE: $code\n</pre>\n";
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return $output;
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}
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function slasharguments($texexp) {
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global $CFG;
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$admin = $CFG->wwwroot.'/'.$CFG->admin.'/settings.php?section=http';
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$image = tex2image($texexp,true);
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echo "<p>If the following image displays correctly, set your ";
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echo "<a href=\"$admin\" target=\"_blank\">Administration->Server->HTTP</a> ";
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echo "setting for slasharguments to file.php/1/pic.jpg: ";
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echo "<img src=\"$CFG->wwwroot/filter/tex/pix.php/$image\" align=\"absmiddle\"></p>\n";
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echo "<p>Otherwise set it to file.php?file=/1/pic.jpg ";
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echo "It should display correctly as ";
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echo "<img src=\"$CFG->wwwroot/filter/tex/pix.php?file=$image\" align=\"absmiddle\"></p>\n";
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echo "<p>If neither equation image displays correctly, please seek ";
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echo "further help at moodle.org at the ";
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echo "<a href=\"http://moodle.org/mod/forum/view.php?id=752&loginguest=true\" target=\"_blank\">";
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echo "Mathematics Tools Forum</a></p>";
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}
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?>
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<html>
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<head><title>TeX Filter Debugger</title></head>
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<body>
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<p>Please enter an algebraic expression <b>without</b> any surrounding $$ into
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the text box below. (Click <a href="#help">here for help.</a>)
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<form action="texdebug.php" method="get"
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target="inlineframe">
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<center>
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<input type="text" name="tex" size="50"
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value="f(x)=\int_{-\infty}^x~e^{-t^2}dt" />
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</center>
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<p>The following tests are available:</p>
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<ol>
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<li><input type="radio" name="action" value="ShowDB" id="ShowDB" />
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<label for="ShowDB">See the cache_filters database entry for this expression (if any).</label></li>
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<li><input type="radio" name="action" value="DeleteDB" id="DeleteDB" />
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<label for="DeleteDB">Delete the cache_filters database entry for this expression (if any).</label></li>
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<li><input type="radio" name="action" value="ShowImageMimetex" id="ShowImageMimetex" checked="checked" />
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<label for="ShowImageMimetex">Show a graphic image of the algebraic expression rendered with mimetex.</label></li>
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<li><input type="radio" name="action" value="ShowImageTex" id="ShowImageTex" />
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<label for="ShowImageTex">Show a graphic image of the algebraic expression rendered with Tex/Ghostscript.</label></li>
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<li><input type="radio" name="action" value="ShowOutputTex" id="ShowOutputTex" />
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<label for="ShowOutputTex">Show command execution output from the algebraic expression rendered with Tex/Ghostscript.</label></li>
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<li><input type="radio" name="action" value="SlashArguments" id="SlashArguments" />
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<label for="SlashArguments">Check slasharguments setting.</label></li>
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</ol>
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<input type="submit" value="Do it!" />
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<input type="hidden" name="sesskey" value="<?php echo sesskey(); ?>" />
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</form> <br /> <br />
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<center>
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<iframe name="inlineframe" align="middle" width="80%" height="200">
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<p>Something is wrong...</p>
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</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/png/svg image file for that expression and to create one if it doesn't exist.
|
||
|
|
It will then use either the LaTex/Ghostscript renderer (using external executables
|
||
|
|
on your system) or the bundled Mimetex executable. The full Latex/Ghostscript
|
||
|
|
renderer produces better results and is tried first.
|
||
|
|
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/png/svg image conversion process does not work.
|
||
|
|
If paths are specified in the filter configuation screen for the three
|
||
|
|
executables these will be tried first. Note that they still must be correctly
|
||
|
|
installed and have the correct permissions. In particular make sure that you
|
||
|
|
have all the packages installed (e.g., on Debian/Ubuntu you need to install
|
||
|
|
the 'tetex-extra' package). Running the 'show command execution' test should
|
||
|
|
give a big clue.
|
||
|
|
If this fails or is not available, the Mimetex executable is tried. If this
|
||
|
|
fails 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>.
|
||
|
|
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>
|