209 lines
9.5 KiB
PHP
209 lines
9.5 KiB
PHP
<?php
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/**
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* Based on LaTeX Rendering Class
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* Copyright (C) 2003 Benjamin Zeiss <zeiss@math.uni-goettingen.de>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library 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 GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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* --------------------------------------------------------------------
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* @author Benjamin Zeiss <zeiss@math.uni-goettingen.de>
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* @version v0.8
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* @package latexrender
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*
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*
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*
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* This is not the original version of the LaTeX rendering class, but a pretty heavy modification of it.
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* Please find the original at http://www.mayer.dial.pipex.com/tex.htm
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* I won't say this is better, just different.
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*
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*/
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class LatexRender {
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// ====================================================================================
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// Variable Definitions
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// ====================================================================================
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var $_picture_path = "";
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var $_tmp_dir = "";
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// i was too lazy to write mutator functions for every single program used
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// just access it outside the class or change it here if nescessary
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var $_latex_path = "/usr/bin/latex";
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var $_dvips_path = "/usr/bin/dvips";
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var $_convert_path = "/usr/bin/convert";
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var $_identify_path="/usr/bin/identify";
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var $_formula_density = 120;
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var $_xsize_limit = 600;
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var $_ysize_limit = 500;
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var $_string_length_limit = 500;
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var $_font_size = 10;
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var $_latexclass = "article"; //install extarticle class if you wish to have smaller font sizes
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var $_tmp_filename;
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var $_image_format = "gif"; //change to png if you prefer
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var $_transparency = false;
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// this most certainly needs to be extended. in the long term it is planned to use
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// a positive list for more security. this is hopefully enough for now. i'd be glad
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// to receive more bad tags !
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var $_latex_tags_blacklist = array(
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"include","def","command","loop","repeat","open","toks","output","input",
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"catcode","name","^^",
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"\\every","\\errhelp","\\errorstopmode","\\scrollmode","\\nonstopmode","\\batchmode",
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"\\read","\\write","csname","\\newhelp","\\uppercase", "\\lowercase","\\relax","\\aftergroup",
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"\\afterassignment","\\expandafter","\\noexpand","\\special"
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);
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var $_errorcode = 0;
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var $_errorextra = "";
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var $_cachefiles = 1;
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var $_extraname = ""; //adds time to stop images being cached by IE
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// ====================================================================================
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// constructor
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// ====================================================================================
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/**
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* Initializes the class
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*
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* @param string path where the rendered pictures should be stored
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* @param string same path, but from the httpd chroot
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*/
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function LatexRender($config_array) {
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$this->_picture_path = $config_array['picture_path'];
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$this->_tmp_dir = $config_array['tmp_dir'];
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$this->_filename = $config_array['filename'];
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$this->_latex_path = $config_array['latex_path'];
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$this->_dvips_path = $config_array['dvips_path'];
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$this->_convert_path = $config_array['convert_path'];
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$this->_transparency = $config_array['transparency'];
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$this->_tmp_filename = md5(rand());
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$this->_image_format = $config_array['filetype'];
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}
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// ====================================================================================
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// private functions
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// ====================================================================================
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/**
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* wraps a minimalistic LaTeX document around the formula and returns a string
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* containing the whole document as string. Customize if you want other fonts for
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* example.
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*
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* @param string formula in LaTeX format
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* @returns minimalistic LaTeX document containing the given formula
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*/
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function wrap_formula($latex_formula) {
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$string = "\documentclass[".$this->_font_size."pt]{".$this->_latexclass."}\n";
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$string .= "\usepackage[latin1]{inputenc}\n";
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$string .= "\usepackage{amsmath}\n";
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$string .= "\usepackage{amsfonts}\n";
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$string .= "\usepackage{amssymb}\n";
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$string .= "\pagestyle{empty}\n";
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$string .= "\begin{document}\n";
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$string .= "$".$latex_formula."$\n";
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$string .= "\end{document}\n";
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return $string;
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}
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/**
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* Renders a LaTeX formula by the using the following method:
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* - write the formula into a wrapped tex-file in a temporary directory
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* and change to it
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* - Create a DVI file using latex (tetex)
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* - Convert DVI file to Postscript (PS) using dvips (tetex)
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* - convert, trim and add transparancy by using 'convert' from the
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* imagemagick package.
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* - Save the resulting image to the picture cache directory using an
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* md5 hash as filename. Already rendered formulas can be found directly
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* this way.
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*
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* @param string LaTeX formula
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* @returns true if the picture has been successfully saved to the picture
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* cache directory
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*/
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function renderLatex($latex_formula) {
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$latex_document = $this->wrap_formula($latex_formula);
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// create temporary latex file
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$fp = fopen($this->_tmp_dir."/".$this->_tmp_filename.".tex","a+");
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fputs($fp,$latex_document);
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fclose($fp);
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if (!is_file($this->_tmp_dir."/".$this->_tmp_filename.".tex")) {
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$this->_errorcode = 1;
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$this->_errorextra = "Unable to create tex file. There are various reasons this might happen, from the wrong latex mode to invalid pathes. <br />The command was: $command";
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return;
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}
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// create temporary dvi file
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$command = $this->_latex_path." --interaction=nonstopmode -output-directory=".$this->_tmp_dir." ".$this->_tmp_dir."/".$this->_tmp_filename.".tex";
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$status_code = exec($command);
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if (!is_file($this->_tmp_dir."/".$this->_tmp_filename.".dvi")) {
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$this->_errorcode = 1;
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$this->_errorextra = "Unable to create dvi file (".$this->_tmp_dir."/".$this->_tmp_filename.".dvi). There are various reasons this might happen, from the wrong latex mode to invalid pathes. <br />The command was: $command";
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return;
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}
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// convert dvi file to postscript using dvips
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$command = $this->_dvips_path." -E ".$this->_tmp_dir."/".$this->_tmp_filename.".dvi"." -o ".$this->_tmp_dir."/".$this->_tmp_filename.".ps";
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$status_code = exec($command);
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if (!is_file($this->_tmp_dir."/".$this->_tmp_filename.".dvi")) {
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$this->_errorcode = 1;
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$this->_errorextra = "Unable to create ps file (".$this->_tmp_dir."/".$this->_tmp_filename.".ps). There are various reasons this might happen, from the wrong latex mode to invalid pathes. <br />The command was: $command";
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return;
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}
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if ($this->_transparency) {
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$trans_string = " -transparent \"#FFFFFF\" ";
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} else {
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$trans_string = "";
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}
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// imagemagick convert ps to image and trim picture
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$command = $this->_convert_path." -quality 100 -unsharp 5 -density ".$this->_formula_density.
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" -trim ".$trans_string." ".$this->_tmp_dir."/".$this->_tmp_filename.".ps ".
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$this->_tmp_dir."/".$this->_tmp_filename.".".$this->_image_format;
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$status_code = exec($command);
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if (!is_file($this->_tmp_dir."/".$this->_tmp_filename.".".$this->_image_format)) {
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$this->_errorcode = 1;
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$this->_errorextra = "Unable to create ".$this->_image_format." file (".$this->_tmp_dir."/".$this->_tmp_filename.$this->_image_format."). There are various reasons this might happen, from the wrong latex mode to invalid pathes. <br />The command was: $command";
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return;
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}
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// copy temporary formula file to cached formula directory
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$filename = $this->_picture_path."/".$this->_filename.".".$this->_image_format;
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$status_code = copy($this->_tmp_dir."/".$this->_tmp_filename.".".$this->_image_format,$filename);
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if (!is_file($this->_tmp_dir."/".$this->_tmp_filename.".".$this->_image_format)) {
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$this->_errorcode = 1;
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$this->_errorextra = "Unable to copy the final file (".$filename."). There are various reasons this might happen, from the wrong latex mode to invalid pathes.";
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return;
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}
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$this->cleanTemporaryDirectory();
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return true;
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}
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/**
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* Cleans the temporary directory
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*/
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function cleanTemporaryDirectory() {
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unlink($this->_tmp_dir."/".$this->_tmp_filename.".tex");
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unlink($this->_tmp_dir."/".$this->_tmp_filename.".aux");
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unlink($this->_tmp_dir."/".$this->_tmp_filename.".log");
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unlink($this->_tmp_dir."/".$this->_tmp_filename.".dvi");
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unlink($this->_tmp_dir."/".$this->_tmp_filename.".ps");
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unlink($this->_tmp_dir."/".$this->_tmp_filename.".".$this->_image_format);
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chdir($current_dir);
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}
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}
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?>
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