PHP验证码-类

1、验证码类文件 CreateImg.class.php

<?php
/**
* @version 1.0
* @author   Ben
* @date 2008-1-30
* @email [e-mail]
* @验证码文件类
* int function imagecolorallocate(resource image, int red, int green, int blue) //为一幅图像分配颜色
* bool function imagefilledrectangle(resource image, int x1, int y1, int x2, int y2, int color) //画一矩形并填充
* bool function imagerectangle(resource image, int x1, int y1, int x2, int y2, int col)   //画一个矩形
* bool function imagesetpixel(resource image, int x, int y, int color)   //画一个单一像素
*/
class ValidationCode
{
private $width , $height , $codenum ;
public $checkcode ;      //产生的验证码
private $checkimage ;      //验证码图片
private $disturbColor = '' ; //干扰像素
/*
* 参数：（宽度，高度，字符个数）
*/
function __construct ( $width = '80' , $height = '20' , $codenum = '4' )
{
   $this -> width = $width ;
   $this -> height = $height ;
   $this -> codenum = $codenum ;
}
function outImg ( )
{
   //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 ) ;
}
/*
   * @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 , $y , $this -> checkcode [ $i ] , $bg_color ) ;
   }
}
function __destruct ( )
{
   unset ( $this -> width , $this -> height , $this -> codenum ) ;
}
}
?>

2、包含文件 imgcode.php

<?php
session_start ( ) ;
require_once ( 'CreateImg.class.php' ) ;
$image = new ValidationCode ( '80' , '20' , '4' ) ;      //图片长度、宽度、字符个数
$image -> outImg ( ) ;
$_SESSION [ 'validationcode' ] = $image -> checkcode ; //存贮验证码到 $_SESSION 中
?>

3、前台文件 image.php

<?php
session_start ( ) ;
$test = $_POST [ 'test' ] ;
$test = strtoupper ( trim ( $test ) ) ;
$submit = $_POST [ 'submit' ] ;
if ( isset ( $submit ) ) {
if ( $test == $_SESSION [ 'validationcode' ] ) {
   echo 'true' ;
} else {
   echo 'false' ;
}
}
?>
 
< html >
< head >
< title > Image < / title >
< meta http - equiv = "content-type" content = "text/html;charset=utf-8" >
<script language = "javascript" >
function newgdcode ( obj , url ) {
obj . src = url + '?nowtime=' + new Date ( ) . getTime ( ) ;
//后面传递一个随机参数，否则在IE7和火狐下，不刷新图片
}
</script>
< body >
< img src = "imgcode.php" alt = "看不清楚，换一张" align = "absmiddle" style = "cursor: pointer;" onclick = "javascript:newgdcode(this," http : //blog.51cto.com/viewpic.php?refimg=" + this.src);" />
< form method = "POST" name = "form1" action = "image.php" >
< input type = "text" name = "test" >
< br / >
< input type = "submit" name = "submit" value = "提交" >
< / form >
< / body >
< / head >
< / html >