How to use PHP verification code class

This article mainly introduces how to use the PHP verification code class. Interested friends can refer to it. I hope it will be helpful to everyone.

The details are as follows:

<?php
/**
* @version 1.0
* @author  bolted snail
* @date 2011-10-15
* @PHP验证码类
* 使用方法：
* $image=new Captcha();
* $image->config(&#39;宽度&#39;,&#39;高度&#39;,&#39;字符个数&#39;,&#39;验证码session索引&#39;);
* $image->create();//这样就会向浏览器输出一张图片
* //所有参数都可以省略，
* 默认是：宽80 高20 字符数4 验证码session索引captcha_code
* 第四个参数即把验证码存到$_SESSION[&#39;captcha_code&#39;]
* 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 Captcha
{
private $width=80,$height=20,$codenum=4;
public $checkcode;   //产生的验证码
private $checkimage;  //验证码图片 
private $disturbColor = &#39;&#39;; //干扰像素
private $session_flag=&#39;captcha_code&#39;;//存到session中的索引
//尝试开始session
function __construct(){
  @session_start();
}
/*
* 参数：（宽度，高度，字符个数）
*/
function config($width=&#39;80&#39;,$height=&#39;20&#39;,$codenum=&#39;4&#39;,$session_flag=&#39;captcha_code&#39;)
{ 
  $this->width=$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);
}
}
?>

Summary: The above is the entire content of this article, I hope it will be helpful to everyone's study.

Related recommendations:

Testing methods and examples of PHP scripts

PHP methods to integrate DISCUZ users

PHP four basic sorting algorithms and two search algorithms

The above is the detailed content of How to use PHP verification code class. For more information, please follow other related articles on the PHP Chinese website!