php 验证码程序_PHP

验证码

        // -------------------------------------------------------------
        // 名称: my_authimg class
        //
        // 用途: 根据图片数字字母验证
        // 实例:
        // $ai = new my_authimg();
        // $ai->render();
        //
        // 判断结果是否正确
        // $ai = new my_authimg();
        // $ai->is_true($str);
        //
        // @作者: hightman
        // @版本: 0.0.0
        // @时间: 2005/05/26
        // $Id: $
        // -------------------------------------------------------------
       
        class my_authimg {
                // public var
                var $width          = 72;
                var $height         = 20;
                var $text_font      = 5;
                var $text_space     = 10;
                var $text_length    = 5;
                var $sess_name      = "＿＿auth_xyz_123__";
                var $num_only       = false;
               
                // private
                var $_top           = 1;
                var $_move          = 3;
                var $_lines         = 5;
               
                function auth_image($params = array()) {
                        settype($params, "array");
                        foreach ($params as $key => $value) {
                                if (isset($this->$key)) {
                                        $this->$key = $value;
                                }
                        }
                        $this->_lines = intval($this->height / 10);
                }
               
                function set_sess_name($name = "") {
                        if (!empty($name)) {
                                $this->sess_name = $name;
                        }
                }
               
                function set_text_length($length = 5) {
                        $this->text_length = $length;
                }
               
                function set_img_size($width = 100, $height = 15) {
                        $this->width = $width;
                        $this->height = $height;
                }
               
                function get_sess_value() {
                        @session_start();
                       
                        $sess_key = $this->sess_name;
                        $sess_value = NULL;               

                        if (isset($_SESSION) && isset($_SESSION[$sess_key])) {
                                $sess_value = $_SESSION[$sess_key];
                                unset($_SESSION[$sess_key]);                               
                        } else {
                                global $HTTP_SESSION_VARS;
                               
                                if (isset($HTTP_SESSION_VARS[$sess_key])) {
                                        $sess_value = $HTTP_SESSION_VARS[$sess_key];
                                        session_unregister($this->sess_name);
                                }
                        }
                       
                        if (isset($GLOBALS[$sess_key])) {
                                unset($GLOBALS[$sess_key]);
                        }

                        return $sess_value;
                }
               
                function is_true($str) {
                        $sess_value = $this->get_sess_value();
                        return (!strcasecmp($sess_value, $str));
                }
               
                function render() {
                        $radix = "123456789";
                        if (!$this->num_only) {
                                $radix .= "ABCDEFGHIJKLMNPQRSTUVWXYZ";
                        }
                        $radix_len = strlen($radix);
      
                        // 种下随机种子
                        mt_srand();

                        // 初始化图片
                        $image          = ImageCreate($this->width, $this->height);
                       
                        // 设定颜色
                        $r = mt_rand() % 255; //2 ? 255 : 0;
                        $g = mt_rand() % 255; //2 ? 255 : 0;
                        $b = mt_rand() % 255; //2 ? 255 : 0;
                        $fgcolor        = ImageColorAllocate($image, $r, $g, $b);
                        $bgcolor        = ImageColorAllocate($image, 255 - $r, 255 - $g, 255 - $b);
                        $silver                = ImageColorAllocate($image, (255 - $r) * 2, (255 - $g) * 2, (255 - $b) * 2);
                       
                        // 生成背景
                        ImageFill($image, 0, 0, $bgcolor);                       
                       
                        // 画出横向干扰线
                        $line_space = ceil($this->height / ($this->_lines + 1));
                        $line_move  = ceil($line_space * 2);
                        for ($i = 1; $i _lines; $i++) {
                                $y  = $line_space * $i;
                                $y2 = $y + (($i - rand(0, 2 * $i)) % 2) * $line_move;
                                ImageLine($image, 0, $y, $this->width, $y2, $silver);
                        }
                       
                        // 画出干扰点
                        $pixel_num = intval($this->height * $this->width / 20);
                        for($i = 0; $i                                 $x = mt_rand() % $this->width;
                                $y = mt_rand() % $this->height;
                                ImageSetPixel($image, $x, $y, $silver);
                        }
                       
                        // 画出字符
                        $rand_str = "";
                        $step_len = intval($this->width / ($this->text_length + 1));
                        $left_len = $step_len - 6;

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                        for ($i = 0; $i text_length; $i++) {
                                $x = $left_len + ($step_len * $i);
                                $y = ($i % 2) * $this->_move + $this->_top;

                                $rand = mt_rand(0, $radix_len - 1);
                                $rand_str .= substr($radix, $rand, 1);
                               
                                ImageString($image, $this->text_font, $x, $y, substr($radix, $rand, 1), $fgcolor);
                        }
                       
                        // 设定 SESSION 值
                        @session_start();
                        if (isset($_SESSION)) {
                                $sess_key = $this->sess_name;
                                $_SESSION[$sess_key] = $rand_str;
                        }
                        else {
                                session_register($this->sess_name, $rand_str);
                        }
                       
                        // 输出图象
                        header("Content-type: image/png");
                        ImagePNG($image);
                        ImageDestroy($image);
                }
        }
?>