<?php
/**
 * Alkivia Chameleon. CAPTCHA code.
 * Creates and shows a CAPTCHA code.
 *
 * @version		$Rev: 477 $
 * @author		Jordi Canals
 * @copyright   Copyright (C) 2009, 2010 Jordi Canals
 * @license		GNU General Public License version 2
 * @link		http://alkivia.org
 * @package		Alkivia
 * @subpackage	Chameleon
 *

	Copyright 2009, 2010 Jordi Canals <devel@jcanals.cat>

	This program is free software; you can redistribute it and/or
	modify it under the terms of the GNU General Public License
	version 2 as published by the Free Software Foundation.

	This program 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 General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

/**
 * Genrates a CAPTCHA code for a given length.
 *
 * @param $len	Lengh for the CAPTCHA code.
 * @return string	Generated code.
 */
function cham_captcha_code( $len = 5 )
{
	$pattern = "23456789BCDFGHJKLMNPRSTVWXYZ";

	$code = '';
	for ( $i = 0; $i < $len; $i++ )
	{
		$code .= $pattern[mt_rand(0,27)];
    }
    return $code;
}


$image	= imagecreatefrompng(dirname(__FILE__) . '/captcha.png');
$color	= imagecolorallocate($image, 0, 0, 0);
$code	= cham_captcha_code();

imagestring($image, 5, 10, 2, $code, $color);

// Save the code on a session var
@session_start();
$_SESSION['captcha_code'] = $code;

header("Content-type: image/png");
imagepng($image);
imagedestroy($image);
?>