<?php

/**

 * Created by PhpStorm.

 * User: Yang

 * Date: 2019/8/13

 * Time: 10:51

 */

class Captcha

{

    private $charset = 'abcdefghkmnprstuvwxyzABCDEFGHKMNPRSTUVWXYZ23456789';//随机因子

    private $code;//验证码

    private $codelen = 4;//验证码长度

    private $width = 130;//宽度

    private $height = 50;//高度

    private $img;//图形资源句柄

    private $font;//指定的字体

    private $fontsize = 20;//指定字体大小

    private $fontcolor;//指定字体颜色

    //构造方法初始化

    public function __construct()

    {

        $this->font = dirname(__FILE__) . '/font/Elephant.ttf';//注意字体路径要写对，否则显示不了图片

    }

    //生成随机码

    private function createCode()

    {

        $_len = strlen($this->charset) - 1;

        for ($i = 0; $i < $this->codelen; $i++) {

            $this->code .= $this->charset[mt_rand(0, $_len)];

        }

    }

    //生成背景

    private function createBg()

    {

        //创建真彩图像资源

        $this->img = imagecreatetruecolor($this->width, $this->height);

        //分配一个随机色

        $color = imagecolorallocate($this->img, mt_rand(157, 255), mt_rand(157, 255), mt_rand(157, 255));

        //画一矩形并填充随机色

        imagefilledrectangle($this->img, 0, $this->height, $this->width, 0, $color);

    }

    //生成文字

    private function createFont()

    {

        $_x = $this->width / $this->codelen;

        for ($i = 0; $i < $this->codelen; $i++) {

            $this->fontcolor = imagecolorallocate($this->img, mt_rand(0, 156), mt_rand(0, 156), mt_rand(0, 156));

            //可以绘制汉字

            //绘制验证码

            imagettftext($this->img, $this->fontsize, mt_rand(-30, 30), $_x * $i + mt_rand(1, 5), $this->height / 1.4, $this->fontcolor, $this->font, $this->code[$i]);

        }

    }

    //生成线条、雪花

    private function createLine()

    {

        //线条

        for ($i = 0; $i < 6; $i++) {

            $color = imagecolorallocate($this->img, mt_rand(0, 156), mt_rand(0, 156), mt_rand(0, 156));

            imageline($this->img, mt_rand(0, $this->width), mt_rand(0, $this->height), mt_rand(0, $this->width), mt_rand(0, $this->height), $color);

        }

        //雪花

        for ($i = 0; $i < 100; $i++) {

            $color = imagecolorallocate($this->img, mt_rand(200, 255), mt_rand(200, 255), mt_rand(200, 255));

            imagestring($this->img, mt_rand(1, 5), mt_rand(0, $this->width), mt_rand(0, $this->height), '*', $color);

        }

    }

    //输出

    private function outPut()

    {

        header('Content-type:image/png');

        imagepng($this->img);

        imagedestroy($this->img);

    }

    //对外生成

    public function createImage()

    {

        $this->createBg();

        $this->createCode();

        $this->createLine();

        $this->createFont();

        $this->outPut();

    }

    //获取验证码

    public function getCode()

    {

        return strtolower($this->code);

    }

}

<?php

/**

 * Created by PhpStorm.

 * User: Yang

 * Date: 2019/8/13

 * Time: 11:02

 */

include "./Captcha.php";

$c = new Captcha();

$c->createImage();