一個比較簡易的php驗證碼

 

<?php

    class captcha {
        public static function generate($width,$height){
            $char_arr = array_merge(range('a','z'),range('A','Z'),range(1,9));
            $rand_keys = array_rand($char_arr,4);
            shuffle($rand_keys);
            $rand_str = ''; //設置初始值
            foreach($rand_keys as $key ){
                $rand_str .= $char_arr[$key]; // 注意是 .=
            }

            //將 $rand_str保存到 session中
            $_SESSION['captcha_code'] = $rand_str;

            $img = p_w_picpathcreatetruecolor($width,$height);

            //增長背景顏色
            $back_color = p_w_picpathcolorallocate($img, mt_rand(160,250), mt_rand(150,240), mt_rand(150,250));

            p_w_picpathfill($img, 0, 0, $back_color);

            //增長像素點
            $pixel_color = p_w_picpathcolorallocate($img, mt_rand(95,190), mt_rand(95,190), mt_rand(95,190));
            for($i=0;$i<40;$i++){

                p_w_picpathsetpixel($img,mt_rand(0,$width),mt_rand(0,$height),$pixel_color);
            }

            //增長線條
            $line_color = p_w_picpathcolorallocate($img, mt_rand(95,190), mt_rand(95,190), mt_rand(95,190));
            for($i=0;$i<3;$i++){

                p_w_picpathline($img,mt_rand(0,$width),mt_rand(0,$height),mt_rand(0,$width),mt_rand(0,$height),$line_color);
            }

            //在圖片上面 添加字體,設置字體顏色
            $str_color = p_w_picpathcolorallocate($img, mt_rand(0,150), mt_rand(0,100), mt_rand(0,140));
            p_w_picpathstring($img, 5, 58, 3, $rand_str, $str_color);

            //顯示圖片
            header("content-type:p_w_picpath/png");
            p_w_picpathpng($img);

            //銷燬圖片
            p_w_picpathdestroy($img);

        }

        public static function checkCode($str){
            if(strtoupper($_SESSION['captcha_code']) == strtoupper($str)){
                return true;
            }else {
                return false;
            }
        }
    }

    //captcha::generate(145, 20);
?>