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Differences Between: [Versions 310 and 403] [Versions 311 and 403] [Versions 39 and 403] [Versions 400 and 403]

   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      require_once("../../config.php");
   7  
   8      if (!filter_is_enabled('algebra')) {
   9          throw new \moodle_exception('filternotenabled');
  10      }
  11  
  12      require_once($CFG->libdir.'/filelib.php');
  13      require_once($CFG->dirroot.'/filter/tex/lib.php');
  14  
  15      $action = optional_param('action', '', PARAM_ALPHANUM);
  16      $algebra = optional_param('algebra', '', PARAM_RAW);
  17  
  18      require_login();
  19      require_capability('moodle/site:config', context_system::instance());
  20      if ($action || $algebra) {
  21          require_sesskey();
  22      }
  23  
  24      if ($algebra && $action) {
  25        $md5 = md5($algebra);
  26        if ($action == 'ShowDB' || $action == 'DeleteDB') {
  27          $texcache = $DB->get_record("cache_filters", array("filter"=>"algebra", "md5key"=>$md5));
  28        }
  29        if ($action == 'ShowDB') {
  30          if ($texcache) {
  31            $output = "DB cache_filters entry for $algebra\n";
  32            $output .= "id = $texcache->id\n";
  33            $output .= "filter = $texcache->filter\n";
  34            $output .= "version = $texcache->version\n";
  35            $output .= "md5key = $texcache->md5key\n";
  36            $output .= "rawtext = $texcache->rawtext\n";
  37            $output .= "timemodified = $texcache->timemodified\n";
  38          } else {
  39            $output = "DB cache_filters entry for $algebra not found\n";
  40          }
  41        }
  42        if ($action == 'DeleteDB') {
  43          if ($texcache) {
  44            $output = "Deleting DB cache_filters entry for $algebra\n";
  45            $result =  $DB->delete_records("cache_filters", array("id"=>$texcache->id));
  46            if ($result) {
  47              $result = 1;
  48            } else {
  49              $result = 0;
  50            }
  51            $output .= "Number of records deleted = $result\n";
  52          } else {
  53            $output = "Could not delete DB cache_filters entry for $algebra\nbecause it could not be found.\n";
  54          }
  55        }
  56        if ($action == 'TeXStage1') {
  57          $output = algebra2tex($algebra);
  58        }
  59        if ($action == 'TexStage2') {
  60          $output = algebra2tex($algebra);
  61          $output = refineTeX($output);
  62        }
  63        if ($action == 'ShowImage'|| $action == 'SlashArguments') {
  64          $output = algebra2tex($algebra);
  65          $output = refineTeX($output);
  66          if ($action == 'ShowImage') {
  67            tex2image($output, $md5);
  68          } else {
  69            slasharguments($output, $md5);
  70          }
  71        } else {
  72          outputText($output);
  73        }
  74        exit;
  75      }
  76  
  77  function algebra2tex($algebra) {
  78    global $CFG;
  79    $algebra = str_replace('&lt;','<',$algebra);
  80    $algebra = str_replace('&gt;','>',$algebra);
  81    $algebra = str_replace('<>','#',$algebra);
  82    $algebra = str_replace('<=','%',$algebra);
  83    $algebra = str_replace('>=','!',$algebra);
  84    $algebra = preg_replace('/([=><%!#] *)-/',"\$1 zeroplace -",$algebra);
  85    $algebra = str_replace('delta','zdelta',$algebra);
  86    $algebra = str_replace('beta','bita',$algebra);
  87    $algebra = str_replace('theta','thita',$algebra);
  88    $algebra = str_replace('zeta','zita',$algebra);
  89    $algebra = str_replace('eta','xeta',$algebra);
  90    $algebra = str_replace('epsilon','zepslon',$algebra);
  91    $algebra = str_replace('upsilon','zupslon',$algebra);
  92    $algebra = preg_replace('!\r\n?!',' ',$algebra);
  93    $algebra = escapeshellarg($algebra);
  94  
  95    if ( (PHP_OS == "WINNT") || (PHP_OS == "WIN32") || (PHP_OS == "Windows") ) {
  96      $cmd  = "cd $CFG->dirroot\\filter\\algebra & algebra2tex.pl x/2";
  97      $test = `$cmd`;
  98      if ($test != '\frac{x}{2}') {
  99        echo "There is a problem with either Perl or the script algebra2tex.pl<br/>";
 100        $ecmd = $cmd . " 2>&1";
 101        echo `$ecmd` . "<br/>\n";
 102        echo "The shell command<br/>$cmd<br/>returned status = $status<br/>\n";
 103        $commandpath = "$CFG->dirroot\\filter\\algebra\\algebra2tex.pl";
 104        if (file_exists($commandpath)) {
 105          echo "The file permissions of algebra2tex.pl are: " . decoct(fileperms($commandpath)) . "<br/>";
 106        }
 107        die;
 108      }
 109      $cmd  = "cd $CFG->dirroot\\filter\\algebra & algebra2tex.pl $algebra";
 110    } else {
 111      $cmd  = "cd $CFG->dirroot/filter/algebra; ./algebra2tex.pl x/2";
 112      $test = `$cmd`;
 113      if ($test != '\frac{x}{2}') {
 114        echo "There is a problem with either Perl or the script algebra2tex.pl<br/>";
 115        $ecmd = $cmd . " 2>&1";
 116        echo `$ecmd` . "<br/>\n";
 117        echo "The shell command<br/>$cmd<br/>returned status = $status<br/>\n";
 118        $commandpath = "$CFG->dirroot/filter/algebra/algebra2tex.pl";
 119        if (file_exists($commandpath)) {
 120          echo "The file permissions of algebra2tex.pl are: " . decoct(fileperms($commandpath)) . "<br/>";
 121        }
 122        die;
 123      }
 124      $cmd  = "cd $CFG->dirroot/filter/algebra; ./algebra2tex.pl $algebra";
 125    }
 126    $texexp = `$cmd`;
 127    return $texexp;
 128  }
 129  
 130  function refineTeX($texexp) {
 131    $texexp = str_replace('zeroplace','',$texexp);
 132    $texexp = str_replace('#','\not= ',$texexp);
 133    $texexp = str_replace('%','\leq ',$texexp);
 134    $texexp = str_replace('!','\geq ',$texexp);
 135    $texexp = str_replace('\left{','{',$texexp);
 136    $texexp = str_replace('\right}','}',$texexp);
 137    $texexp = str_replace('\fun',' ',$texexp);
 138    $texexp = str_replace('infty','\infty',$texexp);
 139    $texexp = str_replace('alpha','\alpha',$texexp);
 140    $texexp = str_replace('gamma','\gamma',$texexp);
 141    $texexp = str_replace('iota','\iota',$texexp);
 142    $texexp = str_replace('kappa','\kappa',$texexp);
 143    $texexp = str_replace('lambda','\lambda',$texexp);
 144    $texexp = str_replace('mu','\mu',$texexp);
 145    $texexp = str_replace('nu','\nu',$texexp);
 146    $texexp = str_replace('xi','\xi',$texexp);
 147    $texexp = str_replace('rho','\rho',$texexp);
 148    $texexp = str_replace('sigma','\sigma',$texexp);
 149    $texexp = str_replace('tau','\tau',$texexp);
 150    $texexp = str_replace('phi','\phi',$texexp);
 151    $texexp = str_replace('chi','\chi',$texexp);
 152    $texexp = str_replace('psi','\psi',$texexp);
 153    $texexp = str_replace('omega','\omega',$texexp);
 154    $texexp = str_replace('zdelta','\delta',$texexp);
 155    $texexp = str_replace('bita','\beta',$texexp);
 156    $texexp = str_replace('thita','\theta',$texexp);
 157    $texexp = str_replace('zita','\zeta',$texexp);
 158    $texexp = str_replace('xeta','\eta',$texexp);
 159    $texexp = str_replace('zepslon','\epsilon',$texexp);
 160    $texexp = str_replace('zupslon','\upsilon',$texexp);
 161    $texexp = str_replace('\mbox{logten}','\mbox{log}_{10}',$texexp);
 162    $texexp = str_replace('\mbox{acos}','\mbox{cos}^{-1}',$texexp);
 163    $texexp = str_replace('\mbox{asin}','\mbox{sin}^{-1}',$texexp);
 164    $texexp = str_replace('\mbox{atan}','\mbox{tan}^{-1}',$texexp);
 165    $texexp = str_replace('\mbox{asec}','\mbox{sec}^{-1}',$texexp);
 166    $texexp = str_replace('\mbox{acsc}','\mbox{csc}^{-1}',$texexp);
 167    $texexp = str_replace('\mbox{acot}','\mbox{cot}^{-1}',$texexp);
 168    $texexp = str_replace('\mbox{acosh}','\mbox{cosh}^{-1}',$texexp);
 169    $texexp = str_replace('\mbox{asinh}','\mbox{sinh}^{-1}',$texexp);
 170    $texexp = str_replace('\mbox{atanh}','\mbox{tanh}^{-1}',$texexp);
 171    $texexp = str_replace('\mbox{asech}','\mbox{sech}^{-1}',$texexp);
 172    $texexp = str_replace('\mbox{acsch}','\mbox{csch}^{-1}',$texexp);
 173    $texexp = str_replace('\mbox{acoth}','\mbox{coth}^{-1}',$texexp);
 174    $texexp = preg_replace('/\\\sqrt{(.+?),(.+?)}/s','\sqrt['. "\$2]{\$1}",$texexp);
 175    $texexp = preg_replace('/\\\mbox{abs}\\\left\((.+?)\\\right\)/s',"|\$1|",$texexp);
 176    $texexp = preg_replace('/\\\log\\\left\((.+?),(.+?)\\\right\)/s','\log_{'. "\$2}\\left(\$1\\right)",$texexp);
 177    $texexp = preg_replace('/(\\\cos|\\\sin|\\\tan|\\\sec|\\\csc|\\\cot)([h]*)\\\left\((.+?),(.+?)\\\right\)/s',"\$1\$2^{". "\$4}\\left(\$3\\right)",$texexp);
 178    $texexp = preg_replace('/\\\int\\\left\((.+?),(.+?),(.+?)\\\right\)/s','\int_'. "{\$2}^{\$3}\$1 ",$texexp);
 179    $texexp = preg_replace('/\\\int\\\left\((.+?d[a-z])\\\right\)/s','\int '. "\$1 ",$texexp);
 180    $texexp = preg_replace('/\\\lim\\\left\((.+?),(.+?),(.+?)\\\right\)/s','\lim_'. "{\$2\\to \$3}\$1 ",$texexp);
 181    return $texexp;
 182  }
 183  
 184  function outputText($texexp) {
 185    header("Content-type: text/html; charset=utf-8");
 186    echo "<html><body><pre>\n";
 187    if ($texexp) {
 188      $texexp = str_replace('<','&lt;',$texexp);
 189      $texexp = str_replace('>','&gt;',$texexp);
 190      $texexp = str_replace('"','&quot;',$texexp);
 191      echo "$texexp\n\n";
 192    } else {
 193      echo "No text output available\n\n";
 194    }
 195    echo "</pre></body></html>\n";
 196  }
 197  
 198  function tex2image($texexp, $md5, $return=false) {
 199      global $CFG;
 200  
 201      if (!$texexp) {
 202          echo 'No tex expresion specified';
 203          return;
 204      }
 205  
 206      $texexp = '\Large ' . $texexp;
 207      $image  = $md5 . ".gif";
 208      $filetype = 'image/gif';
 209      if (!file_exists("$CFG->dataroot/filter/algebra")) {
 210          make_upload_directory("filter/algebra");
 211      }
 212      $pathname = "$CFG->dataroot/filter/algebra/$image";
 213      if (file_exists($pathname)) {
 214          unlink($pathname);
 215      }
 216      $commandpath = filter_tex_get_executable(true);
 217      $cmd = filter_tex_get_cmd($pathname, $texexp);
 218      system($cmd, $status);
 219  
 220      if ($return) {
 221          return $image;
 222      }
 223      if (file_exists($pathname)) {
 224          send_file($pathname, $image);
 225  
 226      } else {
 227          $ecmd = "$cmd 2>&1";
 228          echo `$ecmd` . "<br />\n";
 229          echo "The shell command<br />$cmd<br />returned status = $status<br />\n";
 230          if ($status == 4) {
 231              echo "Status corresponds to illegal instruction<br />\n";
 232          } else if ($status == 11) {
 233              echo "Status corresponds to bus error<br />\n";
 234          } else if ($status == 22) {
 235              echo "Status corresponds to abnormal termination<br />\n";
 236          }
 237          if (file_exists($commandpath)) {
 238              echo "File size of mimetex executable  $commandpath is " . filesize($commandpath) . "<br />";
 239              echo "The file permissions are: " . decoct(fileperms($commandpath)) . "<br />";
 240              if (function_exists("md5_file")) {
 241                  echo "The md5 checksum of the file is " . md5_file($commandpath) . "<br />";
 242              } else {
 243                  $handle = fopen($commandpath,"rb");
 244                  $contents = fread($handle,16384);
 245                  fclose($handle);
 246                  echo "The md5 checksum of the first 16384 bytes is " . md5($contents) . "<br />";
 247              }
 248          } else {
 249              echo "mimetex executable $commandpath not found!<br />";
 250          }
 251          echo "Image not found!";
 252      }
 253  }
 254  
 255  function slasharguments($texexp, $md5) {
 256    global $CFG;
 257    $admin = $CFG->wwwroot.'/'.$CFG->admin.'/settings.php?section=http';
 258    $image = tex2image($texexp,$md5,true);
 259    echo "<p>If the following image displays correctly, set your ";
 260    echo "<a href=\"$admin\" target=\"_blank\">Administration->Server->HTTP</a> ";
 261    echo "setting for slasharguments to file.php/1/pic.jpg: ";
 262    echo "<img src=\"pix.php/$image\" align=\"absmiddle\"></p>\n";
 263    echo "<p>Otherwise set it to file.php?file=/1/pic.jpg ";
 264    echo "It should display correctly as ";
 265    echo "<img src=\"pix.php?file=$image\" align=\"absmiddle\"></p>\n";
 266    echo "<p>If neither equation image displays correctly, please seek ";
 267    echo "further help at moodle.org at the ";
 268    echo "<a href=\"http://moodle.org/mod/forum/view.php?id=752&loginguest=true\" target=\"_blank\">";
 269    echo "Mathematics Tools Forum</a></p>";
 270  }
 271  
 272  ?>
 273  
 274  <html>
 275  <head><title>Algebra Filter Debugger</title></head>
 276  <body>
 277      <p>Please enter an algebraic expression <b>without</b> any surrounding @@ into
 278         the text box below. (Click <a href="#help">here for help.</a>)
 279            <form action="algebradebug.php" method="get"
 280             target="inlineframe">
 281              <center>
 282               <label for="algebra" class="accesshide"><?php print_string('algebraicexpression', 'filter_algebra'); ?></label>
 283               <input type="text" id="algebra" name="algebra" size="50"
 284                      value="sin(z)/(x^2+y^2)" />
 285              </center>
 286             <ol>
 287             <li>First click on this button <button type="submit" name="action" value="ShowDB">Show DB Entry</button>
 288                 to see the cache_filters database entry for this expression.</li>
 289             <li>If the database entry looks corrupt, click on this button to delete it:
 290                 <button type="submit" name="action" value="DeleteDB">Delete DB Entry</button></li>
 291             <li>Now click on this button <button type="submit" name="action" value="TeXStage1">First Stage Tex Translation</button>.
 292                 A preliminary translation into TeX will appear in the box below.</li>
 293             <li>Next click on this button <button type="submit" name="action" value="TexStage2">Second Stage Tex Translation</button>.
 294                 A more refined translation into TeX will appear in the box below.</li>
 295             <li>Then click on this button <button type="submit" name="action" value="ShowImage">Show Image</button>
 296                 to show a graphic image of the algebraic expression.</li>
 297             <li>Finally check your slash arguments setting
 298                 <button type="submit" name="action" value="SlashArguments">Check Slash Arguments</button></li>
 299             </ol>
 300             <input type="hidden" name="sesskey" value="<?php echo sesskey(); ?>" />
 301            </form> <br /> <br />
 302         <center>
 303            <iframe name="inlineframe" align="middle" width="80%" height="200">
 304            &lt;p&gt;Something is wrong...&lt;/p&gt;
 305            </iframe>
 306         </center> <br />
 307  <hr />
 308  <a name="help">
 309  <h2>Debugging Help</h2>
 310  </a>
 311  <p>First here is a brief overview on how the algebra filter works. It
 312  takes an algebra expression and first translates it into TeX.  It first
 313  looks for the TeX translation in the Moodle database in the table cache_filters
 314  in the field rawtext. If not found, it passes the algebraic expression to the
 315  Perl script algebra2tex.pl, which also uses the Perl library AlgParser.pm.
 316  It then saves the TeX translation in the database for subsequent uses and
 317  passes the TeX to the mimetex executable to be converted to a gif image.
 318  Here are a few common things that can go wrong and some suggestions on how
 319  you might try to fix them.</p>
 320  <ol>
 321  <li>Something had gone wrong on a previous occasion when the filter tried to
 322  translate this expression. Then the database entry for that expression contains
 323  a bad TeX translation in the rawtext field (usually blank). You can fix this
 324  by clicking on &quot;Delete DB Entry&quot;</li>
 325  <li>The First Stage TeX Translation gives a &quot;No text output available&quot;
 326  message. If your server is running Windows, this may be due to the fact that
 327  you haven't installed Perl or didn't install it correctly. If your server is
 328  running some version of Unix (e.g. Linux), then this may be due to your Perl
 329  binary being installed in a nonstandard location. To fix this edit the first
 330  line of the algebra2tex.pl script. Another possible problem which may affect
 331  both Unix and Windows servers is that the web server doesn't have execute permission
 332  on the algebra2tex.pl script. In that case change permissions accordingly</li>
 333  <li>The Second Stage TeX Translation produces malformed TeX. This indicates
 334  a bug in the algebra filter. Post the original algebraic expression and the
 335  bad TeX translation in the <a href="http://moodle.org/mod/forum/view.php?id=752">
 336  Mathematics Tools</a> forum in the Using Moodle course on moodle.org.</li>
 337  <li>The TeX to gif image conversion process does not work. If your server is
 338  running Unix, a likely cause is that the mimetex binary you are using is
 339  incompatible with your operating system. You can try compiling it from the
 340  C sources downloaded from <a href="http://www.forkosh.com/mimetex.zip">
 341  http://www.forkosh.com/mimetex.zip</a>. Lastly check the execute permissions
 342  on your mimetex binary, as outlined in item 2 above.</li>
 343  </ol>
 344  </body>
 345  </html>