php ci框架验证码实例分析

php代码：
<div class="codetitle"><a style="CURSOR: pointer" data="78374" class="copybut" id="copybut78374" onclick="doCopy('code78374')"> 代码如下:<div class="codebody" id="code78374">
<?php
class Captcha_code
{
var $width='60';
var $num='4';
var $height='20';
var $name='randcode';
public function __construct($conf="")
{
if($conf!="")
{
foreach($conf as $key=>$value)
{
$this->$key=$value;
}
}
}function show()
{
Header("Content-type: image/gif");
/
初始化
/
$border = 0; //是否要边框 1要:0不要
$how = $this->num; //验证码位数
$w = $this->width; //图片宽度
$h = $this->height; //图片高度
$fontsize = 5; //字体大小
$alpha = "abcdefghijkmnopqrstuvwxyz"; //验证码内容1:字母
$number = "023456789"; //验证码内容2:数字
$randcode = ""; //验证码字符串初始化
srand((double)microtime()1000000); //初始化随机数种子$im = ImageCreate($w,$h); //创建验证图片/
绘制基本框架
/
$bgcolor = ImageColorAllocate($im,255,255); //设置背景颜色
ImageFill($im,$bgcolor); //填充背景色
if($border)
{
$black = ImageColorAllocate($im,0); //设置边框颜色
ImageRectangle($im,$w-1,$h-1,$black);//绘制边框
}/
逐位产生随机字符
/
for($i=0; $i<$how; $i++)
{
$alpha_or_number = mt_rand(0,1); //字母还是数字
$str = $alpha_or_number ? $alpha : $number;
$which = mt_rand(0,strlen($str)-1); //取哪个字符
$code = substr($str,$which,1); //取字符
$j = !$i ? 4 : $j+15; //绘字符位置
$color3 = ImageColorAllocate($im,mt_rand(0,100),100)); //字符随即颜色
ImageChar($im,$fontsize,$j,3,$code,$color3); //绘字符
$randcode .= $code; //逐位加入验证码字符串
}/
添加干扰
/
for($i=0; $i<5; $i++)//绘背景干扰线
{
$color1 = ImageColorAllocate($im,255),255)); //干扰线颜色
ImageArc($im,mt_rand(-5,$w),$h),mt_rand(20,300),200),55,44,$color1); //干扰线
}
for($i=0; $i<$how15; $i++)//绘背景干扰点
{
$color2 = ImageColorAllocate($im,255)); //干扰点颜色
ImageSetPixel($im,$color2); //干扰点
}//把验证码字符串写入session//$this->session->set_userdata(array($this->name=>$randcode));$_SESSION[$this->name]=$randcode;
/绘图结束/
Imagegif($im);
ImageDestroy($im);
/绘图结束/
}
}
?>

调用php代码：
<div class="codetitle"><a style="CURSOR: pointer" data="70088" class="copybut" id="copybut70088" onclick="doCopy('code70088')"> 代码如下:<div class="codebody" id="code70088">
function verify_image() {
$conf['name'] = 'verify_code'; //作为配置参数
$this->load->library('lib_captcha',$conf);
$this->lib_captcha->show();
$yzm_session = $this->session->userdata('verify_code');
echo $yzm_session;
}

html代码：
<div class="codetitle"><a style="CURSOR: pointer" data="48062" class="copybut" id="copybut48062" onclick="doCopy('code48062')"> 代码如下:<div class="codebody" id="code48062">

验证码：

<input type="text" name="verify_text" id="verify_text" class="yzma" value="">

<a href="javascript:changeCode();" class="change_yz">换一张

<dd class="tips_wrong">验证码不正确
<dd class="tips_correct">