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<?php // latex.php // render TeX stuff using latex - this will not work on all platforms // or configurations. Only works on Linux and Mac with appropriate // software installed. // Much of this inspired/copied from Benjamin Zeiss' work class latex { var $temp_dir; var $error; /** * Constructor - create temporary directories and build paths to * external 'helper' binaries. * Other platforms could/should be added */ public function __construct() {< global $CFG; < < // construct directory structure < $this->temp_dir = $CFG->tempdir . "/latex"; < make_temp_directory('latex');> // Construct directory structure. > $this->temp_dir = make_request_directory();} /** * Old syntax of class constructor. Deprecated in PHP7. * * @deprecated since Moodle 3.1 */ public function latex() { debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER); self::__construct(); } /** * Accessor function for support_platform field. * @return boolean value of supported_platform */ function supported() { return $this->supported_platform; } /** * Turn the bit of TeX into a valid latex document * @param string $forumula the TeX formula * @param int $fontsize the font size * @return string the latex document */ function construct_latex_document($formula, $fontsize = 12) { // $fontsize don't affects to formula's size. $density can change size $doc = "\\documentclass[{$fontsize}pt]{article}\n"; $doc .= get_config('filter_tex', 'latexpreamble'); $doc .= "\\pagestyle{empty}\n"; $doc .= "\\begin{document}\n"; if (preg_match("/^[[:space:]]*\\\\begin\\{(gather|align|alignat|multline).?\\}/i", $formula)) { $doc .= "$formula\n"; } else { $doc .= "$ {$formula} $\n"; } $doc .= "\\end{document}\n"; // Sanitize the whole document (rather than just the formula) to make sure no one can bypass sanitization // by using \newcommand in preamble to give an alias to a blocked command. $doc = filter_tex_sanitize_formula($doc); return $doc; } /** * execute an external command, with optional logging * @param string $command command to execute * @param file $log valid open file handle - log info will be written to this file * @return return code from execution of command */ function execute( $command, $log=null ) { $output = array(); exec( $command, $output, $return_code ); if ($log) { fwrite( $log, "COMMAND: $command \n" ); $outputs = implode( "\n", $output ); fwrite( $log, "OUTPUT: $outputs \n" ); fwrite( $log, "RETURN_CODE: $return_code\n " ); } return $return_code; } /** * Render TeX string into gif/png * @param string $formula TeX formula * @param string $filename filename for output (including extension) * @param int $fontsize font size * @param int $density density value for .ps to .gif/.png conversion * @param string $background background color (e.g, #FFFFFF). * @param file $log valid open file handle for optional logging (debugging only) * @return bool true if successful */ function render( $formula, $filename, $fontsize=12, $density=240, $background='', $log=null ) { global $CFG; // quick check - will this work? $pathlatex = get_config('filter_tex', 'pathlatex'); if (empty($pathlatex)) { return false; } $pathlatex = escapeshellarg(trim($pathlatex, " '\"")); $doc = $this->construct_latex_document( $formula, $fontsize ); // construct some file paths $convertformat = get_config('filter_tex', 'convertformat'); if (!strpos($filename, ".{$convertformat}")) { $convertformat = 'png'; } $filename = str_replace(".{$convertformat}", '', $filename); $tex = "$filename.tex"; // Absolute paths won't work with openin_any = p setting. $dvi = "{$this->temp_dir}/$filename.dvi"; $ps = "{$this->temp_dir}/$filename.ps"; $img = "{$this->temp_dir}/$filename.{$convertformat}"; // Change directory to temp dir so that we can work with relative paths. chdir($this->temp_dir); // turn the latex doc into a .tex file in the temp area $fh = fopen( $tex, 'w' ); fputs( $fh, $doc ); fclose( $fh ); // run latex on document $command = "$pathlatex --interaction=nonstopmode --halt-on-error $tex"; if ($this->execute($command, $log)) { // It allways False on Windows // return false; } // run dvips (.dvi to .ps) $pathdvips = escapeshellarg(trim(get_config('filter_tex', 'pathdvips'), " '\"")); $command = "$pathdvips -q -E $dvi -o $ps"; if ($this->execute($command, $log )) { return false; } // Run convert on document (.ps to .gif/.png) or run dvisvgm (.ps to .svg). if ($background) { $bg_opt = "-transparent \"$background\""; // Makes transparent background } else { $bg_opt = ""; } if ($convertformat == 'svg') { $pathdvisvgm = escapeshellarg(trim(get_config('filter_tex', 'pathdvisvgm'), " '\"")); $command = "$pathdvisvgm -E $ps -o $img"; } else { $pathconvert = escapeshellarg(trim(get_config('filter_tex', 'pathconvert'), " '\"")); $command = "$pathconvert -density $density -trim $bg_opt $ps $img"; } if ($this->execute($command, $log )) { return false; } return $img; }< < /** < * Delete files created in temporary area < * Don't forget to copy the final gif/png before calling this < * @param string $filename file base (no extension) < */ < function clean_up( $filename ) { < global $CFG; < < unlink( "{$this->temp_dir}/$filename.tex" ); < unlink( "{$this->temp_dir}/$filename.dvi" ); < unlink( "{$this->temp_dir}/$filename.ps" ); < $convertformat = get_config('filter_tex', 'convertformat'); < unlink( "{$this->temp_dir}/$filename.{$convertformat}" ); < unlink( "{$this->temp_dir}/$filename.aux" ); < unlink( "{$this->temp_dir}/$filename.log" ); < return; < } <}< < <