ci添加任意图片验证码方式

验证码类需要放到用户类库中
只是注意的一点就是记得要清空输出缓存,否则就会造成图片不能显示
D:\Program Files\Apache\htdocs\edm\application\libraries\captcha.php
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<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');

class captcha
{

/**
* 背景图片所在目录
*
* @var string $folder
*/
var $folder = 'images/captcha/';//用于存放背景图片的文件夹,

/**
* 图片的文件类型
*
* @var string $img_type
*/
var $img_type = 'jpeg';

/*------------------------------------------------------ */
//-- 存在session中的名称
/*------------------------------------------------------ */
var $session_word = 'captcha_word';

/**
* 背景图片以及背景颜色
*用于存放背景图片的文件夹中的图片文件,必须存在否则出错,主要是用于随机出现背景图片
* 0 => 背景图片的文件名
* 1 => Red, 2 => Green, 3 => Blue
* @var array $themes
*/
var $themes_jpg = array(
1 => array('captcha_bg1.jpg', 255, 255, 255),
2 => array('captcha_bg2.jpg', 0, 0, 0),
3 => array('captcha_bg3.jpg', 0, 0, 0),
4 => array('captcha_bg4.jpg', 255, 255, 255),
5 => array('captcha_bg5.jpg', 255, 255, 255),
);

var $themes_gif = array(
1 => array('captcha_bg1.gif', 255, 255, 255),
2 => array('captcha_bg2.gif', 0, 0, 0),
3 => array('captcha_bg3.gif', 0, 0, 0),
4 => array('captcha_bg4.gif', 255, 255, 255),
5 => array('captcha_bg5.gif', 255, 255, 255),
);

/**
* 图片的宽度
*
* @var integer $width
*/
var $width = 53;

/**
* 图片的高度
*
* @var integer $height
*/
var $height = 20;

/**
* 构造函数
*
* @access public
* @param string $folder 背景图片所在目录
* @param integer $width 图片宽度
* @param integer $height 图片高度
* @return bool
*/
function captcha($folder = '', $width = 53, $height = 20)
{
session_start();
$this->folder = str_replace('\\', '/', dirname(dirname(dirname(__FILE__)))). "/". $this->folder;

if (!empty($folder))
{
$this->folder = $folder;
}

$this->width = $width;
$this->height = $height;

/* 检查是否支持 GD */
if (PHP_VERSION >= '4.3')
{

return (function_exists('imagecreatetruecolor') || function_exists('imagecreate'));
}
else
{

return (((imagetypes() & IMG_GIF) > 0) || ((imagetypes() & IMG_JPG)) > 0 );
}
}

/**
* 构造函数
*
* @access public
* @param
*
* @return void
*/
function __construct($folder = '', $width = 53, $height = 20)
{
$this->captcha($folder, $width, $height);
}

/**
* 检查给出的验证码是否和session中的一致
*
* @access public
* @param string $word 验证码
* @return bool
*/
function check_word($word)
{
$recorded = isset($_SESSION[$this->session_word]) ? base64_decode($_SESSION[$this->session_word]) : '';
$given = $this->encrypts_word(strtoupper($word));

return (preg_match("/$given/", $recorded));
}

/**
* 生成图片并输出到浏览器
*
* @access public
* @param string $word 验证码
* @return mix
*/
function generate_image($word = false)
{
if (!$word)
{
$word = $this->generate_word();
}

/* 记录验证码到session */
$this->record_word($word);

/* 验证码长度 */
$letters = strlen($word);

/* 选择一个随机的方案 */
mt_srand((double) microtime() * 1000000);

if (function_exists('imagecreatefromjpeg') && ((imagetypes() & IMG_JPG) > 0))
{
$theme = $this->themes_jpg[mt_rand(1, count($this->themes_jpg))];
}
else
{
$theme = $this->themes_gif[mt_rand(1, count($this->themes_gif))];
}

if (!file_exists($this->folder . $theme[0]))
{
return false;
}
else
{
$img_bg = (function_exists('imagecreatefromjpeg') && ((imagetypes() & IMG_JPG) > 0)) ?
imagecreatefromjpeg($this->folder . $theme[0]) : imagecreatefromgif($this->folder . $theme[0]);
$bg_width = imagesx($img_bg);
$bg_height = imagesy($img_bg);

$img_org = ((function_exists('imagecreatetruecolor')) && PHP_VERSION >= '4.3') ?
imagecreatetruecolor($this->width, $this->height) : imagecreate($this->width, $this->height);

/* 将背景图象复制原始图象并调整大小 */
if (function_exists('imagecopyresampled') && PHP_VERSION >= '4.3') // GD 2.x
{
imagecopyresampled($img_org, $img_bg, 0, 0, 0, 0, $this->width, $this->height, $bg_width, $bg_height);
}
else // GD 1.x
{
imagecopyresized($img_org, $img_bg, 0, 0, 0, 0, $this->width, $this->height, $bg_width, $bg_height);
}
imagedestroy($img_bg);

$clr = imagecolorallocate($img_org, $theme[1], $theme[2], $theme[3]);

/* 绘制边框 */
//imagerectangle($img_org, 0, 0, $this->width - 1, $this->height - 1, $clr);

/* 获得验证码的高度和宽度 */
$x = ($this->width - (imagefontwidth(5) * $letters)) / 2;
$y = ($this->height - imagefontheight(5)) / 2;
imagestring($img_org, 5, $x, $y, $word, $clr);
@ob_end_clean();//必须清除,防止配合CI使用时,出现非图片内容.
header('Expires: Thu, 01 Jan 1970 00:00:00 GMT');

// HTTP/1.1
header('Cache-Control: private, no-store, no-cache, must-revalidate');
header('Cache-Control: post-check=0, pre-check=0, max-age=0', false);

// HTTP/1.0
header('Pragma: no-cache');
if ($this->img_type == 'jpeg' && function_exists('imagecreatefromjpeg'))
{
header('Content-type: image/jpeg');
imageinterlace($img_org, 1);
imagejpeg($img_org, false, 95);
}
else
{
header('Content-type: image/png');
imagepng($img_org);
}
imagedestroy($img_org);
return true;
}
}

/*------------------------------------------------------ */
//-- PRIVATE METHODs
/*------------------------------------------------------ */

/**
* 对需要记录的串进行加密
*
* @access private
* @param string $word 原始字符串
* @return string
*/
function encrypts_word($word)
{
return substr(md5($word), 1, 10);
}

/**
* 将验证码保存到session
*
* @access private
* @param string $word 原始字符串
* @return void
*/
function record_word($word)
{
$_SESSION[$this->session_word] = base64_encode($this->encrypts_word($word));
}

/**
* 生成随机的验证码
*
* @access private
* @param integer $length 验证码长度
* @return string
*/
function generate_word($length = 5)
{
$chars = '23456789ABCDEFGHJKLMNPQRSTUVWXYZ';

for ($i = 0, $count = strlen($chars); $i < $count; $i++)
{
$arr[$i] = $chars[$i];
}

mt_srand((double) microtime() * 1000000);
shuffle($arr);

return substr(implode('', $arr), 5, $length);
}
}
--------------
随便在一个控制器中放入调用验证码的方法
我是放在home/init中
-----

/**
*显示认证图片
*/
public function getCaptcha()
{
$this->load->library('captcha');
$this->captcha->generate_image();
exit;
}
------
验证码调用
-----
<img align="验证码" onclick="change_verify(this)" title="点击更换图片/输入时不区分大小写"
src="<?php echo site_url("home/init/getCaptcha");?>">
-----
显示



----
使用回调form验证方式验证输入码
---

/**
*回调认证码验证
*/
function verifyCheck($str){

$this->load->library('captcha');

if ($this->captcha->check_word($str)){
return true;
}else{
$this->form_validation->set_message('verifyCheck', '验证码有误');
return false;
}
}
------
设置回调规则
$this->form_validation->set_rules('verify', '认证码', 'callback_verifyCheck');