<?php
class RandCheckCode
{
        /*函數(shù)名稱:get_code()
        *作用:取得隨機(jī)字符串
        * 參數(shù):
        1、(int)$length = 32 #隨機(jī)字符長度
        2、(int)$mode = 0    #隨機(jī)字符類型，
        0為大小寫英文和數(shù)字,1為數(shù)字,2為小寫字母,3為大寫字母,
        4為大小寫字母,5為大寫字母和數(shù)字,6為小寫字母和數(shù)字
        *返回:取得的字符串
        */
        function get_code($length=32,$mode=0)//獲取隨機(jī)驗證碼函數(shù)
        {
                switch ($mode)
                {
                        case '1':
                                $str='123456789';
                                break;
                        case '2':
                                $str='abcdefghijklmnopqrstuvwxyz';
                                break;
                        case '3':
                                $str='ABCDEFGHIJKLMNOPQRSTUVWXYZ';
                                break;
                        case '4':
                                $str='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';
                                break;
                        case '5':
                                $str='ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890';
                                break;
                        case '6':
                                $str='abcdefghijklmnopqrstuvwxyz1234567890';
                                break;
                        default:
                                $str='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890';
                                break;
                }
                $checkstr='';
                $len=strlen($str)-1;
                for ($i=0;$i<$length;$i++)
                {
                        //$num=rand(0,$len);//產(chǎn)生一個0到$len之間的隨機(jī)數(shù)
                        $num=mt_rand(0,$len);//產(chǎn)生一個0到$len之間的隨機(jī)數(shù)
                        $checkstr.=$str[$num];

                      
                }
                return $checkstr;
        }

/**     函數(shù)名稱:create_check_image()
        函數(shù)作用:產(chǎn)生一個校驗碼的圖片
        參    數(shù):$checkcode:校驗碼字符串
        返 回 值:返回該圖片
*/
        function create_check_image($checkcode)//產(chǎn)生一個
        {
                $im=imagecreate(65,22);//產(chǎn)生一個圖片
                $black=imagecolorallocate($im,0,0,0);//背景顏色
                $white=imagecolorallocate($im,255,255,255);//前景顏色
                $gray=imagecolorallocate($im,200,200,200);
                imagefill($im,30,30,$gray);//在$im圖像的坐標(biāo)30,30(圖像左上角為0,0)處用$gray 顏色執(zhí)行區(qū)域填充(即與30,30點顏色相同且相鄰的點都會被填充)

                imagestring($im,5,8,3,$checkcode,$white);//用$white顏色將字符串$checkcode畫到$im 所代表的圖像的8,3坐標(biāo)處(這是字符串左上角坐標(biāo),整幅圖像的左上角為0,0),5是字體大小, 字體只能是1,2,3,4或5,使用內(nèi)置字體
                for ($i=0;$i<120;$i++)
                {
                        $randcolor=imagecolorallocate($im,rand(0,255),rand(0,255),rand(0,255));
                        imagesetpixel($im,rand()%70,rand()%30,$randcolor);//在$im圖象上用$randcolor顏色在(rand()%70,rand()%30)坐標(biāo)(圖像左上角為0,0)上畫一個點
                }
                header("Content-type:image/png");
                imagepng($im);//以PNG格式將圖像輸出到瀏覽器或文件
                imagedestroy($im);//銷毀圖像$im
        }
}
/*
$randcode=new RandCheckCode();
$checkstring=$randcode->get_code(5,7);
$image=$randcode->create_check_image($checkstring);
echo $image;
*/

?>