php驗證碼類

<?
 /**


驗證碼類
@author  firerat
@email    lukai_rat@163.com
@time     Feb 16  2011 15:28
@lastmodify Feb 16  2011 15:28
*/

class verifycode{
        //image source
        private  $im;
        //圖片寬度
        private  $w;
        //圖片高度
        private  $h;
        //驗證字符集合
        private  $text;
        //字符數
        private $length;
        //字體
        private  $font = array();
        //字體大小
        private  $fontsize = array();
        //字體顏色
        private  $fontcolor = array();
        //字體的偏轉角度
        private  $angel = array();
        //背景色
        private  $backgroundcolor = array();
        //背景圖片
        private $backgroundimage = array();
        //坐標-x
        private $x  ;
        //坐標-y
        private $y  ;
        //驗證碼存放的字段
        private $checkcodefield ;

    /**
     * 構造函數
     *
     */
    public function __construct(){
      //圖片寬度
      $this->w = 500 ;
      //圖片高度
      $this->h = 600;
      //驗證字符
      $this->text = '0123456789qwertyuiopasdfghjklzxcvbnm';
      //字體
      $this->font = array(
             'C:\\WINDOWS\\Fonts\\Ming Imperial.TTF',
             'C:\\WINDOWS\\Fonts\\latha.TTF',
             'C:\\WINDOWS\\Fonts\\ARIALNBI.TTF',
             'C:\\WINDOWS\\Fonts\\GOTHICBI.TTF'
            );
      //字符數
      $this->length = '4';
      //字體大小
      $this->fontsize = array(50,60,70);
      //字體顏色
      $this->fontcolor = array(
             array('red'=>0x14, 'green'=>0x37,'blue'=>0xad),
             array('red'=>0x6e, 'green'=>0x86,'blue'=>0xd6),
             array('red'=>0x2c, 'green'=>0x40 ,'blue'=>0x81),
             array('red'=>0x06, 'green'=>0x1f ,'blue'=>0x70),
             array('red'=>0x14, 'green'=>0x37 ,'blue'=>0xad),
             array('red'=>0x57, 'green'=>0x79 ,'blue'=>0xc0)
      );
      //字體的偏轉角度
      $this->angel = array(2,4,8,-2,-4,-8);
      //背景色
      $this->backgroundcolor = array(
              array('red'=>0x14, 'green'=>0x37,'blue'=>0xad),
              array('red'=>0x6e, 'green'=>0x86,'blue'=>0xd6),
              array('red'=>0x2c, 'green'=>0x40 ,'blue'=>0x81),
              array('red'=>0x06, 'green'=>0x1f ,'blue'=>0x70),
              array('red'=>0x14, 'green'=>0x37 ,'blue'=>0xad),
              array('red'=>0x57, 'green'=>0x79 ,'blue'=>0xc0)
      );

      //背景圖片
      $this->backgroundimage = array(
             'F:\\city_photo\\city_photo\\1\\1807141.jpg',
             'F:\\city_photo\\city_photo\\1\\1807141.jpg',
             'F:\\city_photo\\city_photo\\1\\1807141.jpg',
             'F:\\city_photo\\city_photo\\1\\1807141.jpg',
             'F:\\city_photo\\city_photo\\1\\1807141.jpg'
      );
      //坐標軸X
      $this->x = 100 ;
      //坐標軸Y
      $this->y = 300 ;
      //驗證碼存放的字段
      $this->checkcodefield = 'checkcode';
    }

    /* 創建背景
     *
     * @return $im
     */
    public function createImgae(){
       //$this->im = imagecreatetruecolor($this->w,$this->h);
       $key = array_rand($this->backgroundimage);
       $this->im = imagecreatefromjpeg( $this->backgroundimage[$key]);

       return $this->im;
    }

    /* 創建背景的索引色
     *
     *  @return
     */
    public function createBackgroundColor(){
       //獲取背景隨機顏色組key
       $rgbGroupKey = array_rand($this->backgroundcolor);
       $red = $this->backgroundcolor[$rgbGroupKey]['red'];
       $green = $this->backgroundcolor[$rgbGroupKey]['green'];
       $blue = $this->backgroundcolor[$rgbGroupKey]['blue'];

       //返回顏色索引
       return imagecolorallocate($this->im, $red, $green, $blue);
    }

    /* 獲取隨機字符，并將字符存放發到
     *
     *  @return
     */
    public  function getRandStr(){
       $randChars  = '';
       for($i = 0 ; $i < $this->length ; $i++){
           $randChars .= $this->text[rand(0,strlen($this->text))] ;
       }

       //字體編碼統一轉換為utf-8
       //$randChars = iconv("GB2312","UTF-8",$randChars);

       //寫進session
       $_SESSION[$this->checkcodefield] =  $randChars;

       return  $randChars;
    }

    /* 創建字體顏色索引
     * @return
     */
    public function createFontColor(){
       //獲取背景隨機顏色組key
       $rgbGroupKey = array_rand($this->fontcolor);
       $red = $this->fontcolor[$rgbGroupKey]['red'];
       $green = $this->fontcolor[$rgbGroupKey]['green'];
       $blue = $this->fontcolor[$rgbGroupKey]['blue'];

       //顏色索引
       return  imagecolorallocate($this->im, $red, $green, $blue);;
    }

    //添加文字到圖片
    public function addTextToImage(){
      //字體顏色
      $fontcolor =$this->createFontColor();
      //字體
      $key = array_rand($this->font);
      $font = $this->font[$key];

      //驗證碼
      $text = $this->getRandStr();

      //偏轉角度
      $key = array_rand($this->angel);
      $_angle = $this->angel[$key];

      //起始坐標
      $x = $this->x;
      $y = $this->y;

      //字體大小
      $key = array_rand($this->fontsize);
      $_fontsize = $this->fontsize[$key];

      //添加文字到圖片
      imagettftext($this->im, $_fontsize , $_angle, $x, $y, $fontcolor, $font, $text);
    }

    /**
     * 輸出圖片
     *
     */
    public function outputImage(){
      //創建布景
      $this->createImgae();
      //顏色添加到布景
      $this->createBackgroundColor();
      //添加文字到圖片
      $this->addTextToImage();

      //增加過期,30分鐘后過期
      $expireTime = date("M, d Y H:i:s",time()+1800);
      header("Expires: {$expireTime} GMT ");
      header("Last-Modified: " . gmdate("D, d M Y H:i:s")." GMT");
      header("Cache-Control: no-store, no-cache, must-revalidate");
      header("Cache-Control: post-check=0, pre-check=0", false);
      header("Pragma: no-cache");

      //聲明輸出文件的類型
      header('Content-type: image/png');
      //輸出png圖片
      imagepng($this->im);
      //釋放與此圖片關聯的內存
      imagedestroy($this->im);
    }

}

$instance = new verifycode;
$instance->outputImage();</pre> 

 驗證碼效果圖：