非常实用的php验证码类

<?php 
/** 
 * 
 * @author administrator 
 * 
 */ 
class validatecode{ 
   
  private $width; 
  private $height; 
  private $codenum; 
  private $img_resouce; 
  private $disturbcolornum; 
  private $checkcode; 
   
  function __construct($width=80,$height=20,$codenum=4) { 
    $this->width=$width; 
    $this->height=$height; 
    $this->codenum=$codenum; 
    $this->checkcode=$this->createcheckcode(); 
    $number=floor($width*$height/25); 
    if ($number>240-$codenum) { 
      $this->disturbcolornum=240-$codenum; 
    }else{ 
      $this->disturbcolornum=$number; 
    } 
  } 
   
  public function showimage($fontpath='') { 
    //创建图像背景 
    $this->img_resouce(); 
    //var_dump($img_resouce); 
    //设置干扰元素 
    $this->setdistructcolor(); 
    //向图像中随机画出文本 
    $this->outputtext($fontpath); 
    //输出图像 
    $this->outputimage(); 
  } 
  /** 
   * 
   *获取随机创建的验证码 
   */ 
  public function getcheckcode(){ 
     
  } 
  private function img_resouce(){ 
    //创建一个真彩图像 
    $this->img_resouce=imagecreatetruecolor($this->width,$this->height); 
    //随机设置图像背景 
    $backcolor=imagecolorallocate($this->img_resouce,rand(225,255),rand(225,255),rand(225,255)); 
    //填充颜色 
    imagefill($this->img_resouce, 0, 0, $backcolor); 
    //设置边框背景 
    $border=imagecolorallocate($this->img_resouce, 0,0,0); 
    //画一个矩形 
    imagerectangle($this->img_resouce,0,0,$this->width-1,$this->height-1,$border); 
  } 
  private function setdistructcolor(){ 
    //绘画干扰点 
    for ($i = 0; $i <$this->disturbcolornum; $i++) { 
       
      imagesetpixel($this->img_resouce, rand(1, $this->width-2), rand(1, $this->height-2), rand(0,255)); 
    } 
     
    //绘画干扰线 
    for ($j = 0; $j <3; $j++) { 
      $linecolor=imagecolorallocate($this->img_resouce,rand(0,255),rand(0,255),rand(0,255)); 
      imagearc($this->img_resouce, rand(0,$this->width), rand(0,$this->height), 
       rand(10, 225), rand(20, 150), 
       55, 44, $linecolor); 
    } 
  } 
  private function createcheckcode(){ 
    $code='23456789abcdefghijkmnpqrstuvwxyzabcdefghijkmnpqrstuvwxyz'; 
    $string=''; 
    for ($i = 0; $i < $this->codenum; $i++) { 
       
      $char=$code{rand(0, strlen($code)-1)}; 
      $string.=$char; 
    } 
    return $string; 
  } 
  private function outputtext($fontpath=''){ 
    for ($i = 0; $i < $this->codenum; $i++) { 
      $fontcolor=imagecolorallocate($this->img_resouce, rand(0,128), rand(0, 128), rand(0, 128)); 
      if ($fontpath=='') { 
         
         $fontsize=rand(3, 5); 
         $x=floor($this->width/$this->codenum)*$i+3; 
         $y=rand(0, $this->height-20); 
         imagechar($this->img_resouce, $fontsize, $x, $y, $this->checkcode{$i}, $fontcolor); 
    }else{ 
         $fontsize=rand(12, 16); 
         $x=floor(($this->width-8)/$this->codenum)*$i+8; 
         $y=rand($fontsize, $this->height-15); 
         imagettftext($this->img_resouce,$fontsize,rand(-45,45),$x,$y,$fontcolor,fontpath,$this->checkcode{$i}); 
       } 
    } 
  } 
  private function outputimage() { 
     
    if (imagetypes() & img_gif) { 
      header("content-type: image/gif"); 
      imagegif($this->img_resouce); 
    }else if(imagetypes() & img_jpeg) { 
      header("content-type: image/jpeg"); 
      imagejpeg($this->img_resouce); 
    }else if(imagetypes() & img_png) { 
      header("content-type: image/png"); 
      imagepng($this->img_resouce); 
    }else { 
      echo "php不支持的类型"; 
    } 
     
     
  } 
  private function __destruct(){ 
     
    imagedestroy($this->img_resouce); 
  } 
} 
?>