效果：
myvcode.class.php：封装创建验证码的类
/*<br>* file:myvcode.class.php<br>* 验证码类,类名Vcode<br>*/<br>class Vcode<br>{<br>private $width; /*验证码宽度*/<br>private $height; /*验证码高度*/<br>private $codeNum; /*验证码字符个数*/<br>private $checkCode; /*验证码字符*/<br>private $image; /*验证码资源*/<br>private $pixNum; /*绘制干扰点的个数*/<br>private $lineNum; /*绘制干扰线的条数*/
/*<br>*构造方法实例化验证码对象，并初始化数据<br><a href="mailto:*@param">*@param</a> int $width 设置默认宽度<br><a href="mailto:*@param">*@param</a> int $height 设置默认高度<br><a href="mailto:*@param">*@param</a> int $codeNum 设置验证码中的字符个数<br><a href="mailto:*@param">*@param</a> int $pixNum 设置干扰点的个数<br><a href="mailto:*@param">*@param</a> int $lineNum 设置干扰线的数量<br>*/<br>function __construct($width=80,$height=40,$codeNum=4,$pixNum=40,$lineNum=5)<br>{<br>$this->width = $width;<br>$this->height = $height;<br>$this->codeNum = $codeNum;<br>$this->pixNum = $pixNum;<br>$this->lineNum = $lineNum;<br>}<br>/*内部私有方法,创建图像资源*/<br>private function getCreateImage()<br>{<br>$this->image = imagecreatetruecolor($this->width, $this->height);<br>$white = imagecolorallocate($this->image,0xff,0xff,0xff);<br>imagefill($this->image, 0, 0, $white);<br>$black = imagecolorallocate($this->image,0,0,0);<br>imagerectangle($this->image, 0, 0, $this->width-1, $this->height-1, $black);<br>}<br>/*内部私有方法,绘制字符，去掉o0Llz和012*/<br>private function createCheckCode()<br>{<br>$code = '3456789abcdefghijkmnpqrstuvwxyABCDEFGHIJKMNPQRSTUVWXY';<br>$this->checkCode = "";<br>for($i=0; $icodeNum;$i++)<br>{<br>$char = $code{rand(0,strlen($code) - 1)};<br>$this->checkCode .= $char;<br>$fontColor = imagecolorallocate($this->image, rand(0,128), rand(0,128),rand(0,128));<br>$fontSize = rand(3,5);<br>$x = rand(0,$this->width-imagefontwidth($fontSize));<br>$y = rand(0,$this->height-imagefontheight($fontSize));<br>imagechar($this->image, $fontSize, $x, $y, $char, $fontColor);<br>}<br>}<br>/*内部私有方法设置干扰元素*/<br>private function setDisturbColor()<br>{<br>/*绘制干扰点*/<br>for($i=0; $ipixNum; $i++)<br>{<br>$color = imagecolorallocate($this->image, rand(0,255), rand(0,255), rand(0,255));<br>imagesetpixel($this->image, rand(1,$this->width-2), rand(1,$this->height-2), $color);<br>}<br>/*绘制干扰线*/<br>for($i=0; $ilineNum; $i++)<br>{<br>$color = imagecolorallocate($this->image, rand(0,255), rand(0,255), rand(0,255));<br>imageline($this->image, rand(1,$this->width / 2), rand(1,$this->height / 2),<br>rand($this->width / 2,$this->width – 2), rand($this->height / 2,$this->height – 2), $color);
}<br>}<br>/*开启session保存 利用echo 输出图像*/<br>function __toString()<br>{<br>$_SESSION['code'] = strtoupper($this->checkCode);<br>$this->getCreateImage();<br>$this->createCheckCode();<br>$this->setDisturbColor();<br>$this->outputImg();<br>}<br>/*内部私有方法输出图像*/<br>private function outputImg()<br>{<br>header("content-type:image/png");<br>imagepng($this->image);<br>}<br>/*析构方法，释放对象*/<br>function __destruct()<br>{<br>imagedestroy($this->image);<br>}<br>}<br>?>imgcode.php输出图像
<?php
session_start();
require_once('myvcode.class.php');
echo new Vcode();
?>
test.html:同过img标签引用
<img src="imgcode.php" alt="PHP制作图形验证码代码分享_php实例" >
可以加一个a标签，用js实现换一张效果：
/*局部刷新换验证码*/
function changeCode()
{
var imgcode = document.getElementById(‘code');
var change = document.getElementById(‘change');
change.onclick = function()
{
/*必须加后面的参数才能刷新*/
imgcode.src='code.php?tm'+Math.random();
}
}
code和change分别是img和a的id
