用PHP写一个验证码类，并进行封装。
类名： validationcode.class.php
代码如下：
代码如下:
<?php
class ValidationCode {
private $width;
private $height;
private $codeNum;
private $image; //图像资源
private $disturbColorNum;
private $checkCode;
function __construct($width=80, $height=20, $codeNum=4){
$this->width=$width;
$this->height=$height;
$this->codeNum=$codeNum;
$this->checkCode=$this->createCheckCode();
$number=floor($width*$height/15);
if($number > 240-$codeNum){
$this->disturbColorNum= 240-$codeNum;
}else{
$this->disturbColorNum=$number;
}
}
//通过访问该方法向浏览器中输出图像
function showImage($fontFace=""){
//第一步：创建图像背景
$this->createImage();
//第二步：设置干扰元素
$this->setDisturbColor();
//第三步：向图像中随机画出文本
$this->outputText($fontFace);
//第四步：输出图像
$this->outputImage();
}
//通过调用该方法获取随机创建的验证码字符串
function getCheckCode(){
return $this->checkCode;
}
private function createImage(){
//创建图像资源
$this->image=imagecreatetruecolor($this->width, $this->height);
//随机背景色
$backColor=imagecolorallocate($this->image, rand(225, 255), rand(225,255), rand(225, 255));
//为背景添充颜色
imagefill($this->image, 0, 0, $backColor);
//设置边框颜色
$border=imagecolorallocate($this->image, 0, 0, 0);
//画出矩形边框
imagerectangle($this->image, 0, 0, $this->width-1, $this->height-1, $border);
}
private function setDisturbColor(){
for($i=0; $i<$this->disturbColorNum; $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), $color);
}
for($i=0; $i<10; $i++){
$color=imagecolorallocate($this->image, rand(200, 255), rand(200, 255), rand(200, 255));
imagearc($this->image, rand(-10, $this->width), rand(-10, $this->height), rand(30, 300), rand(20, 200), 55, 44, $color);
}
}
private function createCheckCode(){
//这里主要产生随机码，从2开始是为了区分1和l
$code="23456789abcdefghijkmnpqrstuvwxyzABCDEFGHIJKMNPQRSTUVWXYZ";
