//验证码类
class ValidateCode {private $charset = 'abcdefghkmnprstuvwxyzABCDEFGHKMNPRSTUVWXYZ23456789';//随机因子private $code;//验证码private $codelen = 4;//验证码长度private $width = 130;//宽度private $height = 50;//高度private $img;//图形资源句柄private $font;//指定的字体private $fontsize = 20;//指定字体大小private $fontcolor;//指定字体颜色//构造方法初始化public function __construct() {$this->font = dirname(__FILE__).'/font/elephant.ttf';//注意字体路径要写对，否则显示不了图片}//生成随机码private function createCode() {$_len = strlen($this->charset)-1;for ($i=0;$i<$this->codelen;$i++) {$this->code .= $this->charset[mt_rand(0,$_len)];}}//生成背景private function createBg() {$this->img = imagecreatetruecolor($this->width, $this->height);$color = imagecolorallocate($this->img, mt_rand(157,255), mt_rand(157,255), mt_rand(157,255));imagefilledrectangle($this->img,0,$this->height,$this->width,0,$color);}//生成文字private function createFont() {$_x = $this->width / $this->codelen;for ($i=0;$i<$this->codelen;$i++) {$this->fontcolor = imagecolorallocate($this->img,mt_rand(0,156),mt_rand(0,156),mt_rand(0,156));imagettftext($this->img,$this->fontsize,mt_rand(-30,30),$_x*$i+mt_rand(1,5),$this->height / 1.4,$this->fontcolor,$this->font,$this->code[$i]);}}//生成线条、雪花private function createLine() {//线条for ($i=0;$i<6;$i++) {$color = imagecolorallocate($this->img,mt_rand(0,156),mt_rand(0,156),mt_rand(0,156));imageline($this->img,mt_rand(0,$this->width),mt_rand(0,$this->height),mt_rand(0,$this->width),mt_rand(0,$this->height),$color);}//雪花for ($i=0;$i<100;$i++) {$color = imagecolorallocate($this->img,mt_rand(200,255),mt_rand(200,255),mt_rand(200,255));imagestring($this->img,mt_rand(1,5),mt_rand(0,$this->width),mt_rand(0,$this->height),'*',$color);}}//输出private function outPut() {header('Content-type:image/png');imagepng($this->img);imagedestroy($this->img);}//对外生成public function doimg() {$this->createBg();$this->createCode();$this->createLine();$this->createFont();$this->outPut();}//获取验证码public function getCode() {return strtolower($this->code);}
}
输出实例：
使用方法：
1、先把验证码类保存为一个名为 ValidateCode.class.php 的文件；
2、新建一个名为 captcha.php 的文件进行调用该类；
captcha.php
session_start(); require './ValidateCode.class.php'; //先把类包含进来，实际路径根据实际情况进行修改。 $_vc = new ValidateCode(); //实例化一个对象 $_vc->doimg(); $_SESSION['authnum_session'] = $_vc->getCode();//验证码保存到SESSION中
3、引用到页面中，代码如下：
<img title="点击刷新" src="./captcha.php" align="absbottom" οnclick="this.src='captcha.php?'+Math.random();"></img>
4、一个完整的验证页面，代码如下：
<?php
session_start();
//在页首先要开启session,
//error_reporting(2047);
session_destroy();
//将session去掉，以每次都能取新的session值;
//用seesion 效果不错，也很方便
?>
<html>
<head>
<title>session 图片验证实例</title>
<style type="text/css">
#login p{
margin-top: 15px;
line-height: 20px;
font-size: 14px;
font-weight: bold;
}
#login img{
cursor:pointer;
}
form{
margin-left:20px;
}
</style>
</head>
<body> <form id="login" action="" method="post">此例为session验证实例 <span>验证码：</span>
<input type="text" name="validate" value="" size=10>
<img title="点击刷新" src="./captcha.php" align="absbottom" οnclick="this.src='captcha.php?'+Math.random();"></img><input type="submit"></form>
<?php
//打印上一个session;
//echo "上一个session：<b>".$_SESSION["authnum_session"]."</b><br>";
$validate="";
if(isset($_POST["validate"])){
$validate=$_POST["validate"];
echo "您刚才输入的是：".$_POST["validate"]."<br>状态：";
if($validate!=$_SESSION["authnum_session"]){
//判断session值与用户输入的验证码是否一致;
echo "<font color=red>输入有误</font>";
}else{
echo "<font color=green>通过验证</font>";
}
}
?>
https://www.cnblogs.com/superfeeling/p/4675676.html
