<"329832983DSDSKDSLKQWEWQ2lkfDSFSDjfdsfdsjwlkfj93290KFDSKJFDSOIDSLK";
  public $bg_color = '#DCDCDC';
  public $font_size = 16;
  public $font = 'font.ttf';
  public $font_color = '#000000';
   
  //创建验证码饿字符创
  public function create_code(){
    $code = '';
    for( $i=0;$i<$this->code_len;$i++ ){
      $code .= $this->code_str[mt_rand(0, strlen($this->code_str)-1)];
  }
    return $this->code = $code;
  }
   
  //输出图像
  public function getImage(){
    $w = $this->width;
    $h = $this->height;
    $bg_color = $this->bg_color;
    $img = imagecreatetruecolor($w, $h);
    $bg_color = imagecolorallocate($img, 
  hexdec(substr($bg_color, 1,2)), hexdec(substr($bg_color, 3,2)), hexdec(substr($bg_color, 5,2)));
  imagefill($img, 0, 0, $bg_color);
    $this->img = $img;
    $this->create_font();
    $this->create_pix();
  $this->show_code();
  }
 
 
  //写入验证码
  public function create_font(){
    $this->create_code();
    $color = $this->font_color;
    $font_color = imagecolorallocate($this->img, hexdec(substr($color,1,2)), hexdec(substr($color, 3,2)), hexdec(substr($color,5,2)));
    $x = $this->width/$this->code_len;
    for( $i=0;$i<$this->code_len;$i++ ){
      $txt_color = imagecolorallocate($this->img, mt_rand(0,100), mt_rand(0, 150), mt_rand(0, 200));
      imagettftext($this->img, $this->font_size, mt_rand(-30, 30), $x*$i+mt_rand(3, 6), mt_rand($this->height/1.2, $this->height), $txt_color, $this->font , $this->code[$i]); 
      //imagestring($this->img, $this->font_size, $x*$i+mt_rand(3, 6),mt_rand(0, $this->height/4) , $this->code[$i], $font_color);
    }
    $this->font_color = $font_color;
  }
   
  //画干扰线
  public function create_pix(){
    $pix_color= $this->font_color;
    for($i=0;$i<100;$i++){
      imagesetpixel($this->img, mt_rand(0, $this->width),mt_rand(0, $this->height), $pix_color);
    }
    for($j=0;$j<4;$j++){
      imagesetthickness($this->img, mt_rand(1, 2));
      imageline($this->img, mt_rand(0, $this->width), mt_rand(0, $this->height), mt_rand(0, $this->width), mt_rand(0, $this->height), $pix_color);
    }
  }
   
  //得到验证码
  public function getCode(){
    return strtoupper($this->code);
  }
 
 
  //输出验证码
  private function show_code(){
    header("Content-type:image/png");
    imagepng($this->img);
    imagedestroy($this->img);
  }
}

<"Don't support image type!");
		}
		//将验证码信息保存到session中，md5加密
		if(!isset($_SESSION)){
  		session_start();
		} 
		$_SESSION[$this->sessionKey] = md5($this->captcha);
		
    imagedestroy($this->image); 
	}
	
	function __destruct() {
		unset($this->width, $this->height, $this->codeNum,$this->captcha);
	}
}

<""){
  //第一步：创建图像背景
  $this->createImage();
  //第二步：设置干扰元素
  $this->setDisturbColor();
  //第三步：向图像中随机画出文本
  $this->outputText($fontFace);
  //第四步：输出图像
  $this->outputImage();
 }
 
 //通过调用该方法获取随机创建的验证码字符串
 function getCheckCode(){
  return $this->checkCode;
 }
 private function createImage(){
  //创建图像资源
  $this->image=imagecreatetruecolor($this->width, $this->height);
  //随机背景色
  $backColor=imagecolorallocate($this->image, rand(225, 255), rand(225,255), rand(225, 255));
  //为背景添充颜色
  imagefill($this->image, 0, 0, $backColor);
  //设置边框颜色
  $border=imagecolorallocate($this->image, 0, 0, 0);
  //画出矩形边框
  imagerectangle($this->image, 0, 0, $this->width-1, $this->height-1, $border);
 }
 private function setDisturbColor(){
  for($i=0; $i<$this->disturbColorNum; $i++){
  $color=imagecolorallocate($this->image, rand(0, 255), rand(0, 255), rand(0, 255));
  imagesetpixel($this->image, rand(1, $this->width-2), rand(1, $this->height-2), $color);
  }
  for($i=0; $i<10; $i++){
  $color=imagecolorallocate($this->image, rand(200, 255), rand(200, 255), rand(200, 255));
  imagearc($this->image, rand(-10, $this->width), rand(-10, $this->height), rand(30, 300), rand(20, 200), 55, 44, $color);
  }
 }
 private function createCheckCode(){

//这里主要产生随机码，从2开始是为了区分1和l
  $code="23456789abcdefghijkmnpqrstuvwxyzABCDEFGHIJKMNPQRSTUVWXYZ";
  $string='';
  for($i=0; $i < $this->codeNum; $i++){
  $char=$code{rand(0, strlen($code)-1)};
  $string.=$char;
  }
  return $string;
 }
 private function outputText($fontFace=""){
  for($i=0; $i<$this->codeNum; $i++){
  $fontcolor=imagecolorallocate($this->image, rand(0, 128), rand(0, 128), rand(0, 128));
  if($fontFace==""){
   $fontsize=rand(3, 5);
   $x=floor($this->width/$this->codeNum)*$i+3;
   $y=rand(0, $this->height-15);
   imagechar($this->image,$fontsize, $x, $y, $this->checkCode{$i},$fontcolor);
  }else{
   $fontsize=rand(12, 16);
   $x=floor(($this->width-8)/$this->codeNum)*$i+8;
   $y=rand($fontSize+5, $this->height);
   imagettftext($this->image,$fontsize,rand(-30, 30),$x,$y ,$fontcolor, $fontFace, $this->checkCode{$i});
  }
  }
 }
 private function outputImage() {
  if(imagetypes() & IMG_GIF){
  header("Content-Type:image/gif");
  imagepng($this->image);
  }else if(imagetypes() & IMG_JPG){
  header("Content-Type:image/jpeg");
  imagepng($this->image);
  }else if(imagetypes() & IMG_PNG){
  header("Content-Type:image/png");
  imagepng($this->image);
  }else if(imagetypes() & IMG_WBMP){
  header("Content-Type:image/vnd.wap.wbmp");
  imagepng($this->image);
  }else{
  die("PHP不支持图像创建");
  }
 }
 function __destruct(){
  imagedestroy($this->image);
 }
 }
 

<"validationcode.class.php";
$code=new ValidationCode(80, 20, 4);
$code->showImage();  //输出到页面中供 注册或登录使用
$_SESSION["code"]=$code->getCheckCode(); //将验证码保存到服务器中