<?PHP
// +------------------------------------------------------------------------
// 验证码类，该类的对象能动态获取验证码图片,验证码字符保存在SESSION['code']中 
// +------------------------------------------------------------------------
// 支持4种格式 数字 字母 汉字 混合
// +------------------------------------------------------------------------
// @Author: HelloChina([email protected])                           
// +------------------------------------------------------------------------
// @Date: 2012年6月7日11:03:00                  
// +------------------------------------------------------------------------
// @version 1.0                                                     
// +------------------------------------------------------------------------

    class Vcode{
        protected $width;               //验证码宽度
        protected $height;              //验证码长度
        protected $codeNum;             //验证码字符个数
        protected $codeType;                //验证码类型
        protected $fontSize;                //字符大小
        protected $fontType;                //字体类型
        protected $codeStr;             //中文内容
        protected $strNum;              //中文个数
        protected $imageType;               //输出图片类型
        protected $image;               //图片资源
        protected $checkCode;               //验证码内容
     /**
      +--------------------------------------------------------------------------------
      * 取得验证码信息
      +--------------------------------------------------------------------------------
      * @param integer $width       验证码宽度 
      * @param integer $height      验证码高度 
      * @param integer $codeNum     验证码字符个数 
      * @param integer $codeType    验证码字符类型 1为数字 2为字母 3为汉字 4为混编
      * @param integer $fontSize        验证码字体的大小
      * @param string  $fontType    验证码字体类型
      * @param string  $imageType   验证码输出图片类型
      * @param string  $codestr     中文验证码内容
      +--------------------------------------------------------------------------------
     */
        public function __construct($width=100,$height=50,$codeNum=4,$codeType=4,$fontSize=12,$fontType='heiti.ttf',$imageType='jpeg',$codeStr='去我饿人他一哦平啊是的飞个好就看了在想才吧你吗'){
            $this->width     =  $width;
            $this->height    =  $height;
            $this->codeNum   =  $codeNum;
            $this->codeType  =  $codeType;
            $this->fontSize  =  $fontSize;
            $this->fontType  =  $fontType;
            $this->codeStr   =  $codeStr;
            $this->strNum = strlen($this->codeStr)/3-1;
            $this->imageType =  $imageType;
            $this->checkCode =  $this->getCheckCode();
        }

      //+--------------------------------------------------------------------------------
      //* 生成验证码字符
      //+--------------------------------------------------------------------------------
      //* @return string
      //+--------------------------------------------------------------------------------
        public function __toString(){           
            $string = implode('',$this->getCheckCode());
            $_SESSION["code"]=$string;  //加到session中
            $this->getImage();              //输出验证码
            return '';
        }   
        protected function getCheckCode(){
            $string = array();              
            switch($this->codeType){
                case 1:
                    //数字字符串
                    $string =  array_rand(range(0,9),$this->codeNum);
                    break;
                case 2:
                    //大字母字符串
                    $string = array_rand(array_flip(range('A','Z')),$this->codeNum);
                    break;
                case 3:
                    //汉字字符串

                    for($i=0; $i<($this->codeNum); $i++){
                        $start = mt_rand(0,$this->strNum);
                        $string[$i]= self::msubstr($this->codeStr,$start);
                    }
                    break;
                case 4:
                    //混合字符串
                    for($i=0; $i<($this->codeNum); $i++){
                        $rand=mt_rand(0,2);
                        switch($rand){
                            case 0:
                                $ascii = mt_rand(48,57);
                                $string[$i] = sprintf('%c',$ascii);
                                break;