[Mod] ColorCaptcha

<?php

/**
 * Generates a CAPTCHA picture
 *
 * @copyright Copyright (C) 2008 PunBB, partially based on code by Jamie Furness
 * @license http://www.gnu.org/licenses/gpl.html GPL version 2 or higher
 * @package pun_antispam
 * modified by James Anderson :)
 */

// Generate a random string
function pun_antispam_rand_str()
{
    return strtr(substr(strtolower(md5(uniqid(rand(), 1))), 2, 6), 'abcdef', '165380');
}
//decide what color to use
function pun_antispam_random_color() {
    $random_color = rand(0, 2);
    switch($random_color) {
        case "0";
        $use = "red";
        break;
        case "1";
        $use = "blue";
        break;
        case "2";
        $use = "green";
        break;
    }
    return $use;
}

// Output CAPTCHA string into an image
function pun_antispam_image($string, $usecolor)
{
    $im      = imagecreatetruecolor(100, 18);
    // Make the background white
    imagefilledrectangle($im, 0, 0, 99, 17, 0xFFFFFF);
    //other colors
    $red     = imagecolorallocate($im, 255, 0, 0);
    $blue    = imagecolorallocate($im, 0, 0, 255);
    $green   = imagecolorallocate($im, 0, 168, 20);
    $noise   = imagecolorallocate($im, 255, 0, 0);
    $x = 0;
    while($x <= 5) {
        $color = rand(0,2); //is this character red or blue? make it up
        $pallet = $pallet.$color;    //This attaches a number, 0 or 1, to each character, determining whether it is red or blue
                                    //pallet is an all numerical string. there are no letters in pallet
        $x++;
    }
    //if the first is red, the last has to be blue, and vice versa
    //this is to ensure that there will always be at least one red and at least one blue
    //also if the first one is blue, then the second one is green, and if the last one is blue, then the next to last one is green
    $pallet{0} = rand(0,1);
    if($pallet{0} == 1) { //the first one is blue
        $pallet{5} = 0; //the last one is red
        $pallet{1} = 2; //the second one is green
    }
    elseif($pallet{0} == 0) { //the first one is red
        $pallet{5} = 1; //the last one is blue
        $pallet{4} = 2; //the second to last one is green
    }
    $px      = rand(1,10); //moves it around a bit, x

//draw each character
//reads pallet to see whether the letter is red or blue
    $j = 0;
    while($j <= 5) {
        $color = rand(0, 2);
        if($pallet{$j} == 0) {
            $y = rand(2,4);
            imagestring($im, 5, $px, $y, $string{$j}, $red);
            if($usecolor == "red")
                $list .= $string{$j}; //make the list of red chars
        }
        elseif($pallet{$j} == 1) {
            $y = rand(2,4);
            imagestring($im, 5, $px, $y, $string{$j}, $blue);
            if($usecolor == "blue")
                $list .= $string{$j}; //make the list of blue chars
        }
        elseif($pallet{$j} == 2) {
            $y = rand(2,4);
            imagestring($im, 5, $px, $y, $string{$j}, $green);
            if($usecolor == "green")
                $list .= $string{$j}; //make the list of green chars
        }
        else { die("Something went wrong in pallet. It didn't make any colors."); }
        $j++;
        $px = $px + 15; //move for the next char
    }
    //make some noise
    while($k<(100*18)/1000) { //where it says 1000, raise/lower the value to increase or decrease the noise leve. Higher numbers = LESS noise
        imageline($im, mt_rand(0,100), mt_rand(0,18), mt_rand(0,100), mt_rand(0,18), $noise);
        $k++;
    }
    sleep(1);
    header('Content-type:image/gif');
    header('Cache-Control: no-cache, must-revalidate');
    header('Expires: Mon, 26 Jul 1997 05:00:00 GMT');
    header('Pragma: no-cache');

    imagegif($im, null, 30);
    imagedestroy($im);

    return $list; //the list of red chars
}

session_start();
$pun_antispam_string = pun_antispam_rand_str();
$_SESSION['use_color'] = pun_antispam_random_color();
$_SESSION['pun_antispam_text'] = pun_antispam_image($pun_antispam_string, $_SESSION['use_color']);
?>

<?php
<?php
if(!@defined($_SESSION)) {
    session_start();
}
// Language definitions used in pun_antispam
$lang_pun_antispam = array(
    'Captcha'                        =>    'Captcha',
    'Captcha Info'                    =>    'Please enter <i>only</i> the <b><font color="'.$_SESSION['use_color'].'">'.$_SESSION['use_color'].'</font></b> character(s) in the image.',
    'Invalid Text'                    =>    'The captcha text you entered appears to be wrong. <b>Please <i>only</i> enter the <font color="'.$_SESSION['use_color'].'">'.$_SESSION['use_color'].'</font> character(s).</b>',

    'Captcha admin head'            =>    'Setup which actions are protected by a captcha',
    'Captcha admin info'            =>    'You may enable captcha in certain areas of your forum if you are experiencing problems with spam.',
    'Captcha admin legend'            =>    'Enable Captcha',

    'Captcha registrations info'    =>    'Require a captcha before users may register. This can be helpful to stop spam.',
    'Captcha login info'            =>    'Require a captcha when logging in. This can be helpful to stop brute-force attacks.',
    'Captcha reset info'            =>    'Require a captcha to be entered when a user tries to reset their password.',
    'Captcha guestpost info'        =>    'Require a captcha for guest posting (if enabled one).'
);
?>

($hook = get_hook('po_end_validation')) ? eval($hook) : null;

($hook = get_hook('po_end_validation')) ? @eval($hook) : null;

($hook = get_hook('li_login_form_submitted')) ? eval($hook) : null;

($hook = get_hook('li_login_form_submitted')) ? @eval($hook) : null;

<?php ($hook = get_hook('li_login_pre_remember_me_checkbox')) ? eval($hook) : null; ?>

<?php ($hook = get_hook('li_login_pre_remember_me_checkbox')) ? @eval($hook) : null; ?>