验证码扭曲类

<?php


class  image {
    public  static function code(){
        $str = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz023456789';
        $code = substr(str_shuffle($str),0,4);
        $src= imagecreatetruecolor(60,25);
        $dst = imagecreatetruecolor(60,25);

        $sgray = imagecolorallocate($src,128,128,128);
        $dgray =imagecolorallocate($dst,128,128,128);
        $sblue  = imagecolorallocate($src,255,255,255);


        imagefill($src,0,0,$sgray);
        imagefill($dst,0,0,$dgray);

        imagestring($src,5,5,4,$code,$sblue);

        for($i=0;$i<60;$i++){
            $offset = 3;//最大波动几个像素，纵向
            $round = 2;//扭2个周期，横向
            $posy = round(sin($i*$round*2*M_PI /60)*$offset);
            //round函数，是四舍五入用的，sin函数返回的是小数型
            imagecopy($dst,$src,$i,$posy,$i,0,1,25);
        }
        // 输出图像
        header ( "content-type: image/jpeg" );
        imagejpeg ( $dst);

    }
}