php中文驗證碼

 

<?php
header("content-type: image/png");
  class yanzhengma{
  public $str="你是我的好朋友"; //驗證碼
  public $geshu=4;//驗證碼個數
  public $img;//圖片sourcer
  public function  __construct($geshu){
    $this->geshu=$geshu; //初始化個數
}

   public function yanzhengma($x,$y){
    //創建一個畫布x表示橫座標，y表示縱座標
    $this->img=imagecreatetruecolor($x,$y);//創建畫布,返回畫布句柄
    $rand = strlen($this->str)-2;
    $rand = $rand/2;//中文佔2個字節
    $text_color=imagecolorallocate($this->img,mt_rand(0,255),mt_rand(0,255),mt_rand(0,255));//隨機創建文本的顏色
    $text_color2=imagecolorallocate($this->img,mt_rand(0,255),mt_rand(0,255),mt_rand(0,255));//隨機創建背景的顏色

   $text='';
   for($i=0;$i<$this->geshu;$i++){
       $rand=mt_rand(0,$rand);//得到驗證碼
       $text=$text.substr($this->str,$rand*2,2);
    }


    $text=iconv('gb2312', 'UTF-8', $text);//必須轉換才能用
    imagefill($this->img, 0, 0, $text_color2);//填充背景
    imagettftext ($this->img,20,1,10,30,$text_color,"simkai.ttf",$text);//這個函數用於輸出中文
   //imagestring($img, 30, 40, 40, $text, $text_color);該函數只能用於英文數字
    imagepng($this->img);//顯示圖片
    return $text;//返回驗證碼，用於以後session

  }

  public function destory(){
    imagedestroy($this->img);//一定要關閉資源
  }
   }

   $img= new yanzhengma(5);
   $text=$img->yanzhengma(200,40);
   file_put_contents('1.txt', $text)   ;
   $img->destory();
?>