RosSoft

Helper for rendering LaTeX formulas easy

Usage: in your view,

echo $latex->render(’\displaystyle\int_{0}^{1}\frac{x^{4}\left(1-x\right)^{4}}{1+x^{2}}dx=
\frac{25}{8}-\pi’);

It will create an IMG tag to the destination URL of the image. You need a folder in webroot writable by the web sever

1. Download latexrender, and save class.latexrender.php to vendors/latexrender/

2. Edit class.latexrender.php and change the paths to your apps imagemagik and latex

3. Copy this app/views/helpers/latex.php and change the paths of your temp folder and the destination folder of images (writable by webserver under wwwroot)

<?php
/**
 * Latex Helper
 * Renders some LaTeX formula to a image
 * and returns the <IMG> tag to it
 *
 * You need to set the destination directory under webroot folder
 * to store the images (set write permissions on it)
 *
 * @author RosSoft
 * @version 0.1
 * @license MIT
 *
 * @link http://www.mayer.dial.pipex.com/tex.htm LatexRender
 *
 */

class LatexHelper extends Helper
{
    var $_instance=null;
    
    var $images_url=’img/latex’; // under webroot folder
    
    var $tmp_dir=’/tmp’;
    
    /**
     * Renders the formula and returns the <IMG> tag
     *
     * @param string $formula LaTeX Formula
     * @return string <IMG> tag to the rendered image
     */    
    function render($formula)
    {
        $this->_init();
        
        $url = $this->_instance->getFormulaURL($formula);
        $alt = htmlentities($formula, ENT_QUOTES);
        $alt= str_replace(”\r”,” ”,$alt);
        $alt= str_replace(”\n”,” ”,$alt);
        
        if ($url != false)
        {
            return “<img src=’”.$url.”‘ title=’”.$alt.”‘ alt=’”.$alt.”‘ align=’middle’ />”;
        }
        else
        {
            return ‘[unparseable or potentially dangerous latex formula]‘;
        }            
    }

    function _init()
    {        
        if (! $this->_instance)
        {
            $dest_path=WWW_ROOT. $this->images_url;
            $dest_url=$this->webroot . $this->images_url;
            
            //edit class.latexrender and change the paths to your apps
            vendor(’latexrender/class.latexrender’);
            $this->_instance= new LatexRender($dest_path,$dest_url,$this->tmp_dir);                    
        }
    }
}    
?>