Manual:Running MediaWiki on Windows/math.php

 * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA * * @author Benjamin Zeiss  * @version v0.8 * @package latexrender * */ /** * Error code: * 1. Too long formulas * 2. formula contains tags in the blacklist * 3. formula incorrect, can't be render * 4. can't exec tex command *   maybe directory unwritable,can't create temporary files * 5. formula image too big * 6. can't copy image file to cahed formula directory *   maybe ImageMagick fail */

class LatexRender {

// ====================================================================================   // Variable Definitions // ====================================================================================   var $_picture_path = ""; var $_picture_path_httpd = ""; var $_tmp_dir = ""; // i was too lazy to write mutator functions for every single program used // just access it outside the class or change it here if nescessary var $_latex_path   = 'latex.exe'; var $_dvips_path   = 'dvips.exe'; var $_convert_path = 'convert.exe'; var $_identify_path = 'identify.exe';

var $_formula_density = 120; var $_xsize_limit = 700; var $_ysize_limit = 700; var $_string_length_limit = 800; var $_font_size = 10; var $_latexclass = "article"; //install extarticle class if you wish to have smaller font sizes var $_tmp_filename; var $_image_format = "gif"; //change to png if you prefer // this most certainly needs to be extended. in the long term it is planned to use // a positive list for more security. this is hopefully enough for now. i'd be glad // to receive more bad tags ! var $_latex_tags_blacklist = array(       "include","def","command","loop","repeat","open","toks","output","input",        "catcode","name","^^",        "\\every","\\errhelp","\\errorstopmode","\\scrollmode","\\nonstopmode","\\batchmode",        "\\read","\\write","csname","\\newhelp","\\uppercase", "\\lowercase","\\relax","\\aftergroup",        "\\afterassignment","\\expandafter","\\noexpand","\\special"        ); var $_errorcode = 0; var $_errorextra = "";

// ====================================================================================   // constructor // ====================================================================================

/**    * Initializes the class *    * @param string path where the rendered pictures should be stored * @param string same path, but from the httpd chroot */   function LatexRender($picture_path,$picture_path_httpd,$tmp_dir) { $this->_picture_path = $picture_path; $this->_picture_path_httpd = $picture_path_httpd; $this->_tmp_dir = $tmp_dir; $this->_tmp_filename = md5(rand); }

// ====================================================================================   // public functions // ====================================================================================

/**    * Picture path Mutator function *    * @param string sets the current picture path to a new location */   function setPicturePath($name) { $this->_picture_path = $name; }

/**    * Picture path Mutator function *    * @returns the current picture path */   function getPicturePath { return $this->_picture_path; }

/**    * Picture path HTTPD Mutator function *    * @param string sets the current httpd picture path to a new location */   function setPicturePathHTTPD($name) { $this->_picture_path_httpd = $name; }

/**    * Picture path HTTPD Mutator function *    * @returns the current picture path */   function getPicturePathHTTPD { return $this->_picture_path_httpd; }

/**    * Tries to match the LaTeX Formula given as argument against the * formula cache. If the picture has not been rendered before, it'll    * try to render the formula and drop it in the picture cache directory. *    * @param string formula in LaTeX format * @returns the webserver based URL to a picture which contains the * requested LaTeX formula. If anything fails, the resultvalue is false. */   function getFormulaURL($latex_formula) { // circumvent certain security functions of web-software which // is pretty pointless right here

$latex_formula = preg_replace("/>/i", ">", $latex_formula); $latex_formula = preg_replace("/_image_format; $full_path_filename = $this->getPicturePath."/".$filename;

if (is_file($full_path_filename)) { return $this->getPicturePathHTTPD."/".$filename; } else { // security filter: reject too long formulas if (strlen($latex_formula) > $this->_string_length_limit) { $this->_errorcode = 1; return false; }

// security filter: try to match against LaTeX-Tags Blacklist for ($i=0;$i_latex_tags_blacklist);$i++) { if (stristr($latex_formula,$this->_latex_tags_blacklist[$i])) { $this->_errorcode = 2; return false; }           }

// security checks assume correct formula, let's render it           if ($this->renderLatex($latex_formula)) { return $this->getPicturePathHTTPD."/".$filename; } else { $this->_errorcode = 3; return false; }       }    }

// ====================================================================================   // private functions // ====================================================================================

/**    * wraps a minimalistic LaTeX document around the formula and returns a string * containing the whole document as string. Customize if you want other fonts for * example. *    * @param string formula in LaTeX format * @returns minimalistic LaTeX document containing the given formula */   function wrap_formula($latex_formula) { $string = "\documentclass{".$this->_latexclass."}\n"; $string .= "\usepackage{amsmath}\n"; $string .= "\usepackage{amsfonts}\n"; $string .= "\usepackage{amssymb}\n"; $string .= "\pagestyle{empty}\n"; $string .= "\begin{document}\n"; $string .= "$".$latex_formula."$\n"; $string .= "\end{document}\n";
 * 1)        $string  = "\documentclass[".$this->_font_size."pt]{".$this->_latexclass."}\n";
 * 2)        $string .= "\usepackage[latin1]{inputenc}\n";

return $string; }

/**    * returns the dimensions of a picture file using 'identify' of the * imagemagick tools. The resulting array can be adressed with either * $dim[0] / $dim[1] or $dim["x"] / $dim["y"] *    * @param string path to a picture * @returns array containing the picture dimensions */   function getDimensions($filename) { $output=exec($this->_identify_path." ".$filename); $result=explode(" ",$output); $dim=explode("x",$result[2]); $dim["x"] = $dim[0]; $dim["y"] = $dim[1];

return $dim; }

/**    * Renders a LaTeX formula by the using the following method: * - write the formula into a wrapped tex-file in a temporary directory *   and change to it     *  - Create a DVI file using latex (tetex) * - Convert DVI file to Postscript (PS) using dvips (tetex) * - convert, trim and add transparancy by using 'convert' from the *   imagemagick package. * - Save the resulting image to the picture cache directory using an     *    md5 hash as filename. Already rendered formulas can be found directly *   this way. *    * @param string LaTeX formula * @returns true if the picture has been successfully saved to the picture *         cache directory */   function renderLatex($latex_formula) { $latex_document = $this->wrap_formula($latex_formula);

$current_dir = getcwd;

chdir($this->_tmp_dir);

// create temporary latex file $fp = fopen($this->_tmp_dir."/".$this->_tmp_filename.".tex","a+"); fputs($fp,$latex_document); fclose($fp);

// create temporary dvi file // The \"'s are used in case the path has spaces in it (same as below for dvi)       $command = "\"".$this->_latex_path."\" --interaction=nonstopmode ".$this->_tmp_filename.".tex";        $status_code = exec($command);

if (!$status_code) { $this->cleanTemporaryDirectory; chdir($current_dir); $this->_errorcode = 4; return false; }

// convert dvi file to postscript using dvips $command = "\"".$this->_dvips_path."\" -q -E ".$this->_tmp_filename.".dvi"." -o ".$this->_tmp_filename.".ps"; $status_code = exec($command); // imagemagick convert ps to image and trim picture $command = $this->_convert_path." -density ".$this->_formula_density. " -trim -transparent \"#FFFFFF\" ".$this->_tmp_filename.".ps ". $this->_tmp_filename.".".$this->_image_format;

$status_code = exec($command);

// test picture for correct dimensions $dim = $this->getDimensions($this->_tmp_filename.".".$this->_image_format);

if ( ($dim["x"] > $this->_xsize_limit) or ($dim["y"] > $this->_ysize_limit)) { $this->cleanTemporaryDirectory; chdir($current_dir); $this->_errorcode = 5; $this->_errorextra = ": ". $dim["x"]. "x". number_format($dim["y"],0,"",""); return false; }

// copy temporary formula file to cached formula directory $latex_hash = md5($latex_formula); $filename = $this->getPicturePath."/math-".$latex_hash.".".$this->_image_format;

$status_code = copy($this->_tmp_filename.".".$this->_image_format,$filename);

$this->cleanTemporaryDirectory;

if (!$status_code) { chdir($current_dir); $this->_errorcode = 6; return false; }       chdir($current_dir);

return true; }

/**    * Cleans the temporary directory */   function cleanTemporaryDirectory { $current_dir = getcwd; chdir($this->_tmp_dir);

unlink($this->_tmp_dir."/".$this->_tmp_filename.".tex"); unlink($this->_tmp_dir."/".$this->_tmp_filename.".aux"); unlink($this->_tmp_dir."/".$this->_tmp_filename.".log"); unlink($this->_tmp_dir."/".$this->_tmp_filename.".dvi"); unlink($this->_tmp_dir."/".$this->_tmp_filename.".ps"); unlink($this->_tmp_dir."/".$this->_tmp_filename.".".$this->_image_format);

chdir($current_dir); }

}

/** * LaTeX Rendering Class - Calling function * Copyright (C) 2003 Benjamin Zeiss  * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA * * @author Benjamin Zeiss  * @version v0.8 * @package latexrender * Revised by Steve Mayer * This file can be included in many PHP programs by using something like (see example.php to see how it can be used) *             include_once('/full_path_here_to/latexrender/latex.php'); *             $text_to_be_converted=latex_content($text_to_be_converted); * $text_to_be_converted will then contain the link to the appropriate image * or an error code as follows (the 500 values can be altered in class.latexrender.php): *     0 OK *      1 Formula longer than 500 characters *     2 Includes a blacklisted tag *     3 (Not used) Latex rendering failed *     4 Cannot create DVI file *     5 Picture larger than 500 x 500 followed by x x y dimensions *     6 Cannot copy image to pictures directory */ class MathRenderer { function renderMath($latex_formula) {

global $wgMathDirectory, $wgMathPath, $wgTmpDirectory, $wgLaTexCommand, $wgDvipsCommand, $wgImageMagickConvertCommand, $wgImageMagickIdentifyCommand; $latex_formula = '\displaystyle '. $latex_formula; $latex = new LatexRender ($wgMathDirectory, $wgMathPath, $wgTmpDirectory);

#check Math dir if(!file_exists($wgMathDirectory)) @mkdir($wgMathDirectory); if(!file_exists($wgTmpDirectory)) @mkdir($wgTmpDirectory);

$latex->_latex_path         = $wgLaTexCommand; $latex->_dvips_path         = $wgDvipsCommand; $latex->_convert_path       = $wgImageMagickConvertCommand; $latex->_identify_path      = $wgImageMagickIdentifyCommand;

$url = $latex->getFormulaURL($latex_formula);

$alt_latex_formula = htmlentities($latex_formula, ENT_QUOTES); $alt_latex_formula = str_replace("\r"," ",$alt_latex_formula); $alt_latex_formula = str_replace("\n"," ",$alt_latex_formula); $alt_latex_formula = str_replace('\displaystyle ','',$alt_latex_formula);

if ($url != false) $text = ""; else $text = "[Unparseable or potentially dangerous latex formula. Error $latex->_errorcode $latex->_errorextra]";

return $text; } }

?>