1 <?php 2  3 class Captcha 4 { 5     private $width; 6     private $height; 7     private $codeNum; 8     private $code; 9     private $im;10 11     function __construct($width=80, $height=20, $codeNum=4)12     {13         $this->width = $width;14         $this->height = $height;15         $this->codeNum = $codeNum;16     }17 18     function showImg()19     {20         //创建图片21         $this->createImg();22         //设置干扰元素23         $this->setDisturb();24         //设置验证码25         $this->setCaptcha();26         //输出图片27         $this->outputImg();28     }29 //http://www.cnblogs.com/sosoft/30     function getCaptcha()31     {32         return $this->code;33     }34 35     private function createImg()36     {37         $this->im = imagecreatetruecolor($this->width, $this->height);38         $bgColor = imagecolorallocate($this->im, 0, 0, 0);39         imagefill($this->im, 0, 0, $bgColor);40     }41 42     private function setDisturb()43     {44         $area = ($this->width * $this->height) / 20;45         $disturbNum = ($area > 250) ? 250 : $area;46         //加入点干扰47         for ($i = 0; $i < $disturbNum; $i++) {48             $color = imagecolorallocate($this->im, rand(0, 255), rand(0, 255), rand(0, 255));49             imagesetpixel($this->im, rand(1, $this->width - 2), rand(1, $this->height - 2), $color);50         }51         //加入弧线52         for ($i = 0; $i <= 5; $i++) {53             $color = imagecolorallocate($this->im, rand(128, 255), rand(125, 255), rand(100, 255));54             imagearc($this->im, rand(0, $this->width), rand(0, $this->height), rand(30, 300), rand(20, 200), 50, 30, $color);55         }56     }57 58     private function createCode()59     {60         $str = "23456789abcdefghijkmnpqrstuvwxyzABCDEFGHIJKMNPQRSTUVWXYZ";61 62         for ($i = 0; $i < $this->codeNum; $i++) {63             $this->code .= $str{rand(0, strlen($str) - 1)};64         }65     }66 67     private function setCaptcha()68     {69         $this->createCode();70 71         for ($i = 0; $i < $this->codeNum; $i++) {72             $color = imagecolorallocate($this->im, rand(50, 250), rand(100, 250), rand(128, 250));73             $size = rand(floor($this->height / 5), floor($this->height / 3));74             $x = floor($this->width / $this->codeNum) * $i + 5;75             $y = rand(0, $this->height - 20);76             imagechar($this->im, $size, $x, $y, $this->code{$i}, $color);77         }78     }79 80     private function outputImg()81     {82         if (imagetypes() & IMG_JPG) {83             header('Content-type:image/jpeg');84             imagejpeg($this->im);85         } elseif (imagetypes() & IMG_GIF) {86             header('Content-type: image/gif');87             imagegif($this->im);88         } elseif (imagetype() & IMG_PNG) {89             header('Content-type: image/png');90             imagepng($this->im);91         } else {92             die("Don't support image type!");93         }94     }95 96 }
?>