<?php
    class Vcode {
    private $width; //宽
    private $height; //高
    private $num;  //数量
    private $code; //验证码
    private $img;  //图像的资源

    //构造方法， 三个参数
        function __construct($width=80, $height=20, $num=4) {
            $this->width = $width;
            $this->height = $height;
            $this->num = $num;
            $this->code = $this->createcode(); //调用自己的方法
        }

        //获取字符的验证码， 用于保存在服务器中
        function getcode() {
            return $this->code;
        }

        //输出图像
        function outimg() {
            //创建背景 (颜色， 大小， 边框)
            $this->createback();

            //画字 (大小， 字体颜色)
            $this->outstring();

            //干扰元素(点， 线条)

            $this->setdisturbcolor();
            //输出图像
            $this->printimg();
        }

        //创建背景
        private function createback() {
            //创建资源
            $this->img = imagecreatetruecolor($this->width, $this->height);
            //设置随机的背景颜色
            $bgcolor = imagecolorallocate($this->img, rand(225, 255), rand(225, 255), rand(225, 255));
            //设置背景填充
            imagefill($this->img, 0, 0, $bgcolor);
            //画边框
            $bordercolor = imagecolorallocate($this->img, 0, 0, 0);

            imagerectangle($this->img, 0, 0, $this->width-1, $this->height-1, $bordercolor);
        }

        //画字
        private function outstring() {
            for($i=0; $i<$this->num; $i++) {

                $color= imagecolorallocate($this->img, rand(0, 128), rand(0, 128), rand(0, 128));

            $fontsize=rand(3,5); //字体大小

            $x = 3+($this->width/$this->num)*$i; //水平位置
            $y = rand(0, imagefontheight($fontsize)-3);

        //画出每个字符
            imagechar($this->img, $fontsize, $x, $y, $this->code{$i}, $color);
            }
        }

        //设置干扰元素
        private function setdisturbcolor() {
        //加上点数
            for($i=0; $i<100; $i++) {
                $color= imagecolorallocate($this->img, rand(0, 255), rand(0, 255), rand(0, 255));
                imagesetpixel($this->img, rand(1, $this->width-2), rand(1, $this->height-2), $color);
            }

        //加线条
            for($i=0; $i<10; $i++) {
                $color= imagecolorallocate($this->img, rand(0, 255), rand(0, 128), rand(0, 255));
                imagearc($this->img,rand(-10, $this->width+10), rand(-10, $this->height+10), rand(30, 300), rand(30, 300), 55,44, $color);
            }
        }

        //输出图像
        private function printimg() {
            if (imagetypes() & IMG_GIF) {
                header("Content-type: image/gif");
                imagegif($this->img);
            } elseif (function_exists("imagejpeg")) {
                header("Content-type: image/jpeg");
                imagegif($this->img);
            } elseif (imagetypes() & IMG_PNG) {
                header("Content-type: image/png");
                imagegif($this->img);
            } else {
                die("No image support in this PHP server");
            }

        }

        //生成验证码字符串
        private function createcode() {
            $codes = "3456789abcdefghijkmnpqrstuvwxyABCDEFGHIJKLMNPQRSTUVWXY";

            $code = "";

            for($i=0; $i < $this->num; $i++) {
                $code .=$codes{rand(0, strlen($codes)-1)};
            }

            return $code;
        }

        //用于自动销毁图像资源
        function __destruct() {
            imagedestroy($this->img);
        }

    }
    ?>