php 生成验证码

版权声明：阿西莫多 https://blog.csdn.net/yang_yun_hao/article/details/84066038

php 生成验证码的类

<?php
/**
 * @version 1.0
 * @author   bolted snail
 * @date 2011-10-15
 * @email [email protected]
 * @PHP验证码类
 * 使用方法：
 * $image=new Captcha();
 * $image->config('宽度','高度','字符个数','验证码session索引');
 * $image->create();//这样就会向浏览器输出一张图片
 * 如：
 * new Captcha(80,20,4,'captcha_code');
 * //所有参数都可以省略，
 * 默认是：宽80 高20 字符数4 验证码session索引captcha_code
 * 第四个参数即把验证码存到$_SESSION['captcha_code']
 * 最简单使用示例:
 * $image=new Captcha();
 * $image->create();//这样就会向浏览器输出一张图片
 */
class CaptchaController extends AppController
{
    private $width=102,$height=34,$codenum=4;
    public $checkcode;     //产生的验证码
    private $checkimage;    //验证码图片
    private $disturbColor = ''; //干扰像素
    private $session_flag='captcha_code';//存到session中的索引

    //尝试开始session
    function __construct(){
        @session_start();
    }
    /*
    * 参数：（宽度，高度，字符个数）
    */
    function config($width='80',$height='20',$codenum='4',$session_flag='captcha_code')
    {
        $this->width=$width;
        $this->height=$height;
        $this->codenum=$codenum;
        $this->session_flag=$session_flag;
    }
    function create()
    {
        //输出头
        $this->outFileHeader();
        //产生验证码
        $this->createCode();

        //产生图片
        $this->createImage();
        //设置干扰像素
        $this->setDisturbColor();
        //往图片上写验证码
        $this->writeCheckCodeToImage();
        imagepng($this->checkimage);
        imagedestroy($this->checkimage);
        $_SESSION[$this->session_flag]=$this->checkcode;
    }
    /*
       * @brief 输出头
       */
    private function outFileHeader()
    {
        header ("Content-type: image/png");
    }
    /**
     * 产生验证码
     */
    private function createCode()
    {
        $this->checkcode = strtoupper(substr(md5(rand()),0,$this->codenum));
    }
    /**
     * 产生验证码图片
     */
    private function createImage()
    {
        $this->checkimage = @imagecreate($this->width,$this->height);
        $back = imagecolorallocate($this->checkimage,255,255,255);
        $border = imagecolorallocate($this->checkimage,0,0,0);
        imagefilledrectangle($this->checkimage,0,0,$this->width - 1,$this->height - 1,$back); // 白色底
        imagerectangle($this->checkimage,0,0,$this->width - 1,$this->height - 1,$border);   // 黑色边框
    }
    /**
     * 设置图片的干扰像素
     */
    private function setDisturbColor()
    {
        for ($i=0;$i<=200;$i++)
        {
            $this->disturbColor = imagecolorallocate($this->checkimage, rand(0,255), rand(0,255), rand(0,255));
            imagesetpixel($this->checkimage,rand(2,128),rand(2,38),$this->disturbColor);
        }
    }
    /**
     *
     * 在验证码图片上逐个画上验证码
     *
     */
    private function writeCheckCodeToImage()
    {
        for ($i=0;$i<$this->codenum;$i++)
        {
            $bg_color = imagecolorallocate ($this->checkimage, rand(0,255), rand(0,128), rand(0,255));
            $x = floor($this->width/$this->codenum)*$i;
            $y = rand(0,$this->height-15);
            imagechar ($this->checkimage, rand(5,8), $x+5, $y, $this->checkcode[$i], $bg_color);
        }
    }
    function __destruct()
    {
        unset($this->width,$this->height,$this->codenum,$this->session_flag);
    }
}
?>

使用方法

1.前端页面

<li class="validate">
    <input type="text" id="code" placeholder="请输入验证码"/>
    <img id="captcha_img" src="/Users/captcha?time=0.7279450597531716" alt=""/>
</li>

2.js代码段

// 输入验证码后 验证码错误 自动 生成新二维码替换代码（js）
var src = $('#captcha_img').attr('src') + '?time=' + Math.random();
$('#captcha_img').attr('src', src);

// 点击更换验证码 (js)
$('#captcha_img').click(function () {
    var src = $(this).attr('src') + '?time=' + Math.random();
    $(this).attr('src', src);
});

3.php 代码段

// php 代码生成
public function captcha()
{
    $this->autoRender = false; // 禁止使用模板
    include 'CaptchaController.php'; // 引入二维码类
    $Captcha = new CaptchaController(); // 实例化类
    return $Captcha->create(); // 生成图片
}