php 验证码2

<?php

/**

* 图片验证码生成

* @copyright (c) Emlog All Rights Reserved

*/

session_start();

$randCode = '';

$chars = 'abcdefghijkmnpqrstuvwxyzABCDEFGHIJKLMNPRSTUVWXYZ23456789';

for ( $i = 0; $i < 5; $i++ ){

$randCode .= substr($chars, mt_rand(0, strlen($chars) - 1), 1);

}

$_SESSION['chkcode'] = strtolower($randCode);

$img = imagecreate(70,22);

$bgColor = isset($_GET['mode']) && $_GET['mode'] == 't' ? imagecolorallocate($img,245,245,245) : imagecolorallocate($img,255,255,255);

$pixColor = imagecolorallocate($img,mt_rand(30, 180), mt_rand(10, 100), mt_rand(40, 250));

for($i = 0; $i < 5; $i++){

$x = $i * 13 + mt_rand(0, 4) - 2;

$y = mt_rand(0, 3);

$text_color = imagecolorallocate($img, mt_rand(30, 180), mt_rand(10, 100), mt_rand(40, 250));

imagechar($img, 5, $x + 5, $y + 3, $randCode[$i], $text_color);

}

for($j = 0; $j < 60; $j++){

$x = mt_rand(0,70);

$y = mt_rand(0,22);

imagesetpixel($img,$x,$y,$pixColor);

}

header('Content-Type: image/png');

imagepng($img);

imagedestroy($img);