, 2009
* Licensed under GNU GPLv2.0
*
* LatexImg plugin provides ability to insert snippets of LaTeX into a page that are
* rendered as either .gif or .png images. This is useful for adding mathematical
* equations to a wiki page.
*
* LatexImg plugin is built upon LaTeX Rendering Class 0.8, (c) 2003/2004 Benjamin Zeiss
* See the file "LatexImg/class.latexrender.php" for licensing and further details.
*
* Syntax: insert {tex}Some Latex markup, e.g. E = mc^2{/tex}
*
* Explanation of error codes:
*
* 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 LatexImg {
// Description array for the ListPlugins plugin
var $desc = array(
array("LatexImgv0.1", "supports the insertion of snippets of LaTeX into a wiki page that are rendered as .gif or .png images.")
);
// This holds the LatexRender object
var $latex;
// Data array to hold details of Latex snippets between first and second parse
var $latex_data = array();
/* Constructor */
function LatexImg()
{
global $REAL_PATH, $PLUGINS_DIR, $PLUGINS_DATA_DIR;
// Setup important directories for LatexImg
$lateximg_dir = $PLUGINS_DIR . 'LatexImg';
$lateximg_data_dir = $PLUGINS_DATA_DIR . 'LatexImg';
$pictures_dir = $lateximg_data_dir . '/pictures';
$tmp_dir = $lateximg_data_dir . '/tmp';
// Include LatexImg configuration variables
include_once($REAL_PATH . $lateximg_dir . '/config.php');
// Include the LatexRender class
include_once($REAL_PATH . $lateximg_dir . '/class.latexrender.php');
// Check existence of data and tmp directories
foreach(array($lateximg_data_dir , $tmp_dir) as $DIR)
if(!file_exists($DIR)) {
mkdir($DIR, 0777);
$f = fopen($REAL_PATH . $DIR . "/.htaccess", "w");
fwrite($f, "deny from all");
fclose($f);
}
// Check existence of pictures directory. Has to allow http requests.
if(!file_exists($pictures_dir)) {
mkdir($pictures_dir, 0777);
$f = fopen($REAL_PATH . $pictures_dir . "/.htaccess", "w");
fwrite($f, "allow from all");
fclose($f);
}
// Get a new latex renderer
$this->latex = new LatexRender($REAL_PATH . $pictures_dir, $pictures_dir, $REAL_PATH . $tmp_dir);
// Set output image format
$this->latex->_image_format = $LATEXIMG_IMAGE_FORMAT;
// Set up the paths to the utilities that latexrender needs to run
$this->latex->_latex_path = $LATEXIMG_LATEX_PATH;
$this->latex->_dvips_path = $LATEXIMG_DVIPS_PATH;
$this->latex->_convert_path = $LATEXIMG_CONVERT_PATH;
$this->latex->_identify_path = $LATEXIMG_IDENTIFY_PATH;
}
/* Template hook */
function template()
{
global $HEAD, $PLUGINS_DIR;
// Include css for minimal styling on Latex images
$HEAD .= '';
}
/* subPagesLoaded hook.
* Main processing of LaTeX markup. This is done before the main LionWiki syntax parsing
* because many of the elements of LionWiki syntax constructions, e.g. { ,^ and }, commonly
* occur inside LaTeX markup and would be misinterpreted. */
function subPagesLoaded()
{
// Import the content to be processed
global $CON;
// Detect all latex markup
preg_match_all("/(?latex_data = array();
for ($i = 0, $c = count($tex_matches[0]); $i < $c; $i++) {
$pos = strpos($CON, $tex_matches[0][$i]);
$latex_formula = $tex_matches[1][$i];
// Get a link to the image (this also makes the image if it doesn't exist yet)
$this->latex_data[0][$i] = $this->latex->getFormulaURL($latex_formula);
// Build a string for the alt attribute that displays the original LaTeX markup
$alt_latex_formula = htmlentities($latex_formula, ENT_QUOTES);
$alt_latex_formula = str_replace("\r", "
", $alt_latex_formula);
$alt_latex_formula = str_replace("\n", "
", $alt_latex_formula);
$this->latex_data[1][$i] = $alt_latex_formula;
// Check whether latexrenderer successfully returned an image
if ($this->latex_data[0][$i] != false)
// If so, replace the LaTeX markup with {tex} placeholder
$CON = substr_replace($CON, "{TEX}", $pos, strlen($tex_matches[0][$i]));
else
// If not, display the error code
$CON = substr_replace($CON, "[LatexImg Error" . $this->latex->_errorcode . " " . $this->latex->_errorextra . "]", $pos, strlen($tex_matches[0][$i]));
}
}
/* formatEnd hook. Replaces {tex} placeholders with images */
function formatEnd()
{
// Import the content to be processed
global $CON;
// Detect all {TEX} placeholders
preg_match_all("/\{TEX\}/", $CON, $tex_matches);
// Go through each {TEX} placeholder and replace it with an image
for ($i = 0; $i < count($tex_matches[0]); $i++) {
$pos = strpos($CON, $tex_matches[0][$i]);
$CON = substr_replace($CON, "![" . $this->latex_data[1][$i] ."](" . $this->latex_data[0][$i] . " "\" . $this->latex_data[1][$i] . \"")
", $pos, strlen($tex_matches[0][$i]));
}
}
}