PHP制作图形验证码代码分享

效果：

myvcode.class.php：封装创建验证码的类

<?php
/*
* file:myvcode.class.php
* 验证码类,类名vcode
*/
class vcode
{
private $width;              /*验证码宽度*/
private $height;             /*验证码高度*/
private $codenum;            /*验证码字符个数*/
private $checkcode;            /*验证码字符*/
private $image;                /*验证码资源*/
private $pixnum;            /*绘制干扰点的个数*/
private $linenum;            /*绘制干扰线的条数*/

/*
*构造方法实例化验证码对象，并初始化数据
*@param int $width         设置默认宽度
*@param int $height     设置默认高度
*@param int $codenum    设置验证码中的字符个数
*@param int $pixnum        设置干扰点的个数
*@param int $linenum    设置干扰线的数量
*/
function __construct($width=80,$height=40,$codenum=4,$pixnum=40,$linenum=5)
{
$this->width = $width;
$this->height = $height;
$this->codenum = $codenum;
$this->pixnum = $pixnum;
$this->linenum = $linenum;
}
/*内部私有方法,创建图像资源*/
private function getcreateimage()
{
$this->image = imagecreatetruecolor($this->width, $this->height);
$white = imagecolorallocate($this->image,0xff,0xff,0xff);
imagefill($this->image, 0, 0, $white);
$black = imagecolorallocate($this->image,0,0,0);
imagerectangle($this->image, 0, 0, $this->width-1, $this->height-1, $black);
}
/*内部私有方法,绘制字符，去掉o0llz和012*/
private function createcheckcode()
{
$code = '3456789abcdefghijkmnpqrstuvwxyabcdefghijkmnpqrstuvwxy';
$this->checkcode = "";
for($i=0; $i<$this->codenum;$i++)
{
$char = $code{rand(0,strlen($code) - 1)};
$this->checkcode .= $char;
$fontcolor = imagecolorallocate($this->image, rand(0,128), rand(0,128),rand(0,128));
$fontsize = rand(3,5);
$x = rand(0,$this->width-imagefontwidth($fontsize));
$y = rand(0,$this->height-imagefontheight($fontsize));
imagechar($this->image, $fontsize, $x, $y, $char, $fontcolor);
}
}
/*内部私有方法设置干扰元素*/
private function setdisturbcolor()
{
/*绘制干扰点*/
for($i=0; $i<$this->pixnum; $i++)
{
$color = imagecolorallocate($this->image, rand(0,255), rand(0,255), rand(0,255));
imagesetpixel($this->image, rand(1,$this->width-2), rand(1,$this->height-2), $color);
}
/*绘制干扰线*/
for($i=0; $i<$this->linenum; $i++)
{
$color = imagecolorallocate($this->image, rand(0,255), rand(0,255), rand(0,255));
imageline($this->image, rand(1,$this->width / 2), rand(1,$this->height / 2),
rand($this->width / 2,$this->width – 2), rand($this->height / 2,$this->height – 2), $color);

}
}
/*开启session保存 利用echo 输出图像*/
function __tostring()
{
$_session['code'] = strtoupper($this->checkcode);
$this->getcreateimage();
$this->createcheckcode();
$this->setdisturbcolor();
$this->outputimg();
}
/*内部私有方法输出图像*/
private function outputimg()
{
header("content-type:image/png");
imagepng($this->image);
}
/*析构方法，释放对象*/
function __destruct()
{
imagedestroy($this->image);
}
}
?>

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">

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