PHP验证码类代码 功能比较齐全

/**
 * 验证码类
 */
class VeriCode{
    // 获取验证码配置
    private static function _getCodeConfig(){
        return  [
            // 验证码字符集
            'codeStr' => 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789',
            // 验证码个数
            'codeCount' => 4,
            // 字体大小
            'fontsize' =>16,
            // 验证码的宽度
            'width' => 100,
            // 验证码高度
            'height' => 36,
            // 是否有干扰点?true有,false没有
            'disturbPoint' => true,
            // 干扰点个数,disturbPoint开启后生效
            'pointCount' => 200,
            // 是否有干扰条?true有,false没有
            'disturbLine' => true,
            // 干扰条个数,disturbLine开启后生效
            'lineCount' => 3
        ];
    }

    // 创建图片验证码
    public static function create(){
        // 配置
        $config = self::_getCodeConfig();

        //创建画布
        $image = imagecreatetruecolor($config['width'],$config['height']);
        //背景颜色
        $bgcolor=imagecolorallocate($image,255,255,255);
        imagefill($image,0,0,$bgcolor);
        $captch_code = '';//存储验证码
        $captchCodeArr = str_split($config['codeStr']);

        //随机选取4个候选字符
        for($i=0;$i<$config['codeCount'];$i++){
            $fontsize = $config['fontsize'];
            $fontcolor=imagecolorallocate($image,rand(0,120),rand(0,120),rand(0,120));//随机颜色
            $fontcontent = $captchCodeArr[rand(0,strlen($config['codeStr'])-1)];
            $captch_code.=$fontcontent;
            $_x = $config['width']/$config['codeCount'];
            $x=($i*(int)$_x)+rand(5,10);   //随机坐标
            $y=rand(5,10);
            imagestring($image,$fontsize,$x,$y,$fontcontent,$fontcolor);   // 水平地画一行字符串
        }
        session_start();
        $_SESSION['code']=$captch_code;
        //增加干扰点
        if($config['disturbPoint']){
            for($i=0;$i<$config['pointCount'];$i++){
                $pointcolor=imagecolorallocate($image,rand(50,200),rand(50,200),rand(50,200));
                imagesetpixel($image,rand(1,99),rand(1,29),$pointcolor);
            }
        }

        //增加干扰线
        if($config['disturbLine']){
            for($i=0;$i<$config['lineCount'];$i++){
                $linecolor=imagecolorallocate($image,rand(80,280),rand(80,220),rand(80,220));
                imageline($image,rand(1,99),rand(1,29),rand(1,99),rand(1,29),$linecolor);
            }
        }

        //输出格式
        header('content-type:image/png');
        imagepng($image);

        //销毁图片
        imagedestroy($image);
    }
}