效果如图：
文件都放到了同一文件夹下。
************************************容易出现的问题*************
1.未开启php_gd2.dll 去php.ini将其前面的“ ;”去掉
2.上面的checks.php中<?前面有空格或者内容
3.字符编码改为统一的
4.最容易忽略的一点：
5.如果copy代码到你的项目中图片显示为×，检查你的checks.php放置路径
你本机上的环境是将报错提示全部打开的,所以在输出时有系统的未定义提示信息也跟着一起输出了,这样生成的图片肯定就不正常了,方法有两,在ValidationCode.php和checks.php文件开头加上ini_set('display_errors', 'Off'); 就ok了
**********************************************************
CreateImage.class.php
<?php
class ValidationCode
{
private $width,$height,$codenum;
public $checkcode; //产生的验证码
private $checkimage; //验证码图片
private $disturbColor = ''; //干扰像素
function __construct($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);
}
private function outFileHeader()
{
header ('Content-type: image/png');
}
private function createCode()
{
$this->checkcode = strtoupper(substr(md5(rand()),0,$this->codenum));
}
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
}
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);
}
}
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);
}
}
checks.php
<?php
ini_set('display_errors','off');
session_start();
header("content-type:image/png"); //设置创建图像的格式
$image_width=70; //设置图像宽度
$image_height=18; //设置图像高度
srand(microtime()*100000); //设置随机数的种子
for($i=0;$i<4;$i++){ //循环输出一个4位的随机数
$new_number.=dechex(rand(0,15));
}
$_SESSION[check_checks]=$new_number; //将获取的随机数验证码写入到SESSION变量中
$num_image=imagecreate($image_width,$image_height); //创建一个画布
imagecolorallocate($num_image,255,255,255); //设置画布的颜色
for($i=0;$i<strlen($_SESSION[check_checks]);$i++){ //循环读取SESSION变量中的验证码
$font=mt_rand(3,5); //设置随机的字体
$x=mt_rand(1,8)+$image_width*$i/4; //设置随机字符所在位置的X坐标
$y=mt_rand(1,$image_height/4); //设置随机字符所在位置的Y坐标
$color=imagecolorallocate($num_image,mt_rand(0,100),mt_rand(0,150),mt_rand(0,200)); //设置字符的颜色
imagestring($num_image,$font,$x,$y,$_SESSION[check_checks][$i],$color); //水平输出字符
}
imagepng($num_image); //生成PNG格式的图像
imagedestroy($num_image); //释放图像资源
?>
index.php
<?php
header("content-type:text/html; charset=utf-8");
session_start();
if(!empty($_POST["Submit"])){
$checks=$_POST["checks"];
if($checks==""){
echo "<script> alert('验证码不能为空');window.location.href='index.php';</script>";
}
if($checks==$_SESSION[check_checks]){
echo "<script> alert('用户登录成功!');window.location.href='index.php';</script>";
}else{
echo "<script> alert('您输入的验证码不正确!');window.location.href='index.php';</script>";
}
}
?>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>rand函数的应用</title>
<style type="text/css">
<!--
.STYLE1 {
font-size: 12px;
color: #FFFFFF;
font-weight: bold;
}
.style2 {font-weight: bold; font-size: 12px;}
-->
</style>
</head>
<body>
<form name="form" method="post" action="">
<input type="hidden" name="Submit" id="Submit" value="1" />
<table width="1003" border="0" cellspacing="0" cellpadding="0">
<tr>
<td width="168" height="169" background="images/index_01.gif"> </td>
<td width="685" background="images/index_02.gif"> </td>
<td width="150" background="images/index_03.gif"> </td>
</tr>
<tr>
<td width="168" height="311" background="images/index_04.gif"> </td>
<td background="images/index_05.gif"><table width="675" height="169" border="0" cellpadding="0" cellspacing="0">
<tr>
<td height="43" align="center" valign="baseline"> </td>
<td align="center" valign="middle"> </td>
<td align="center" valign="baseline"> </td>
</tr>
<tr>
<td width="382" height="24" align="center" valign="baseline"> </td>
<td width="207" height="24" valign="middle"><span class="style2">用户名</span><span class="STYLE1">
<input name="txt_user" id="txt_user" style="height:20px " size="10">
</span></td>
<td width="86" height="24" align="center" valign="baseline"> </td>
</tr>
<tr>
<td height="24" align="center" valign="baseline"> </td>
<td height="24" valign="middle"><span class="style2">密码</span><span class="STYLE1">
<input name="txt_pwd" type="password" id="txt_pwd" style="FONT-SIZE: 9pt; height:20px" size="10">
</span></td>
<td height="24" align="center" valign="baseline"> </td>
</tr>
<tr>
<td height="24" align="center" valign="baseline"> </td>
<td height="24" valign="middle"><span class="style2">验证码</span><span class="STYLE1">
<input name="checks" size="6" style="height:20px ">
<img src="./checks.php" width="70" height="18" border="0" align="bottom"></span> </td>
<td height="24" align="center" valign="baseline"> </td>
</tr>
<tr>
<td height="40" align="center" valign="baseline"> </td>
<td align="center" valign="baseline"> <input type="submit" id="Submit" name="Submit" value="登录" /></td>
<td align="center" valign="baseline"> </td>
</tr>
</table></td>
<td background="images/index_06.gif"> </td>
</tr>
<tr>
<td height="100"> </td>
<td> </td>
<td> </td>
</tr>
</table>
</form>
</body>
</html>