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<?php
/**
* Created by PhpStorm.
* User: Administrator
* Date: 2016/6/20
* Time: 14:29
*/
Class captcha{
//验证码类
protected $str="xaaxqwe556232assd"; //随机数
protected $code; //验证码
protected $length=4; //验证码长度
protected $width=80; //验证码宽度
protected $height=30; //验证码高度
protected $img;//验证码生成
//随机数
public function getcode()
{
$len=strlen($this->str)-1;
for($i=0;$i<4;$i++)
{
$this->code.=$this->str[mt_rand(0,$len)];
}
}
//生成背景
public function codeBg()
{
//新建一个图像
$this->img=imagecreatetruecolor($this->width,$this->height);
$color=imagecolorallocate($this->img,rand(1,100),rand(1,100),rand(1,100)); //红，绿，蓝
//$back=imagecolorallocate($this->img,0,0,0);
imagefilledrectangle($this->img,0,0,$this->width,$this->height,$color);
}
//生成干扰元素
public function setLine()
{
//干扰点
for($i=0;$i<1000;$i++)
{
$color=imagecolorallocate($this->img,rand(0,255),rand(0,255),rand(0,255));
imagesetpixel($this->img,rand(1,99),rand(1,99),$color);
}
//
// //干扰线
for($i=0;$i<5;$i++)
{
$color=imagecolorallocate($this->img,rand(0,255),rand(0,255),rand(0,255));
imageline($this->img,rand(0,$this->width),rand(0,$this->height),rand(0,$this->width),rand(0,$this->height),$color);
}
//
// //干扰线
}
//生成元素头
public function outHeader()
{
header("Content-type:image/png");
}
//写入验证码
public function writeString()
{
$red = imagecolorallocate ( $this->img , 255 , 0 , 0 );
imagestring($this->img,5,rand(1,15),rand(1,15),$this->code(),$red);
//$font = ‘arial.ttf‘ ;
//imagettftext ( $this->img , 20 , 0 , 10 , 20 , $red , $font , $this->code );
}
//shu
public function png()
{
$this->outHeader();
$this->codeBg();
$this->getcode();
$this->setLine();
$this->writeString();
session_start();
$_SESSION[‘code‘]=$this->code();
imagepng($this->img);
}
public function code(){
return strtoupper($this->code);
}
}
$ce=new captcha();
$ce->png();
var_dump($_SESSION[‘code‘]);
测试页面
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
<title>Examples</title>
<meta name="description" content="">
<meta name="keywords" content="">
<link href="" rel="stylesheet">
</head>
<?php session_start(); ?>
<body>
<img title="点击刷新" src="./captcha.class.php" onclick="this.src=‘captcha.class.php?‘+Math.random();"/>
<form action="<?php $_SERVER[‘PHP_SELF‘]; ?>" method="post">
<input type="text" name=‘captcha‘ />
<input type="submit" name=‘submit‘ value="buton" />
</form>
</body>
</html>
<?php
if($_POST[‘submit‘]){
if($_POST[‘captcha‘]!==$_SESSION[‘code‘])
{
echo "登录失败";
}else{
echo "成功";
}
}
?>
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原文地址：http://www.cnblogs.com/mengluo/p/5608673.html
