生成驗證碼

啥也不說，直接上代碼

 1 class Captcha
 2 {
 3 
 4     /**
 5      * 生成驗證碼
 6      *
 7      * @param int $length 碼字符長度
 8      * @param int $width 寬度
 9      * @param int $height 長度
10      * @param string $type 類型
11      * @return string
12      */
13     public static function createCode($length = 4, $width = 45, $height = 30, $type = 'png')
14     {
15         session_start();
16         $code = self::randCode($length);
17         $_SESSION['captcha'] = $code;
18         $img = @imagecreatetruecolor($width, $height); //新建一個真彩色圖像
19         //畫一矩形並填充
20         $color = imagecolorallocate($img, mt_rand(200, 255), mt_rand(200, 255), mt_rand(200, 255));
21         @imagefilledrectangle($img, 0, 0, $width, $height, $color);
22         //干擾線
23         for ($i = 0; $i < 3; $i++) {
24             $color = imagecolorallocate($img, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
25             @imageline($img, mt_rand(0, $width), mt_rand(0, $height), mt_rand(0, $width), mt_rand(0, $height), $color);
26         }
27         //畫驗證碼
28         $codeColor = imagecolorallocate($img, mt_rand(0, 200), mt_rand(0, 120), mt_rand(0, 120));
29         @imagestring($img, 5, 5, 8, $code, $codeColor);
30         //生成圖像
31         header("Content-type: Image/" . $type);
32         $ImageFun = 'Image' . $type;
33         $ImageFun($img);
34         imagedestroy($img);
35     }
36 
37     /**
38      * 生成隨機驗證碼
39      *
40      * @param int $length 生成長度
41      * @return string
42      */
43     public static function randCode($length)
44     {
45         $string = "0123456789abcdefghijklmnopqrstuvwxyz";
46         $code = '';
47         for ($i = 0; $i < $length; $i++) {
48             $code .= $string[mt_rand(0, strlen($string) - 1)];
49         }
50         return $code;
51     }
52 }