vcode.php

<?php
require_once('include/db_info.inc.php');
    /****************************************
    *  验证码 v0.9
    *  Powerd by awaysoft.com
    *  本组件采用GPLv3发布
    *  2011-07-15
    ****************************************/
    /* $len 为随机字符串长度，$type为类型，a为字符数字，c为字符,n为数字， 已经去除可能误导的字符 */
    function get_rand_string($len=4, $type="n")
    {
        if ($len < 0) {
            $len = 4;
        }
        if ($type == 'a') {
            $chars = 'ABCDEFGHJKMNPQRSTUVWXYZabcdefghijkmnpqrstuvwxyz023456789';
        } elseif ($type == 'c') {
            $chars = 'ABCDEFGHJKMNPQRSTUVWXYZabcdefghijkmnpqrstuvwxyz';
        } elseif ($type == 'n') {
            $chars = '0123456789';
        } else {
            $chars = '0123456789';
        }
        
        $result = '';
        for ($i = 0; $i < $len; $i ++) {
            $index = mt_rand(0, strlen($chars) - 1);
            $result .= substr($chars, $index, 1);
        }
        return $result;
    }
    
   header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
header("Last-Modified: ".gmdate("D, d M Y H:i:s")." GMT");
header("Cache-Control: no-cache, must-revalidate");
header("Pramga: no-cache");

    
    /* 输出图片类型，字符长度，类型 */
    $imgtype = 'gif';
    $len = 4;
    $vcodetype = 'n';
    
    $width = 15 * $len;
    $height = 24;
    /* 生成随机字符串并写入SESSION */
    $vcode = get_rand_string($len, $vcodetype);
    $_SESSION[$OJ_NAME.'_'.'vcode'] = $vcode;
    header("Content-type: image/".$imgtype);
    
    if ($imgtype != 'gif' && function_exists('imagecreatetruecolor')) {
        $im = imagecreatetruecolor($width, $height);
    } else {
        $im = imagecreate($width, $height);
    }
    
    $r = mt_rand(0, 255);
    $g = mt_rand(0, 255);
    $b = mt_rand(0, 255);
    /* 生成背景颜色 */
    $backColor = ImageColorAllocate($im, $r, $g, $b);
    /* 生成边框颜色 */
    $borderColor = ImageColorAllocate($im, 0, 0, 0);
    /* 生成干扰点颜色 */
    $pointColor = ImageColorAllocate($im, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
    
    /* 背景位置 */
    imagefilledrectangle($im, 0, 0, $width - 1, $height - 1, $backColor);
    /* 边框位置 */
    imagerectangle($im, 0, 0, $width - 1, $height - 1, $borderColor);
    
    /* 字符串颜色(背景反色) */
    $stringColor = ImageColorAllocate($im, 255 - $r, 255 - $g, 255 - $b);
    
    /* 产生干扰点 */
    $pointNumber = mt_rand($len * 25, $len * 50);
    for ($i=0; $i<=$pointNumber; $i++) {
        $pointX = mt_rand(2, $width-2);
        $pointY = mt_rand(2, $height-2);
        imagesetpixel($im, $pointX, $pointY, $pointColor);
    }
    
    imagettftext($im, 15, 0, 4, 20, $stringColor, "include/Vera.ttf", $vcode);
    $image_out = 'Image' . $imgtype;
    $image_out($im);
    @ImageDestroy($im);