PHP实现随机数字、字母的验证码功能

　　可自定义生成验证码文字的大小、数量、干扰项等等，也可以自定义验证文字的字体。。。

　　废话不多说，直接上代码：

1、classgd.class.php

<?phpClass Captcha{    private $_fontfile="";    private $_size=36;    private $_width=200;    private $_height=100;    private $_length=4;    private $_image=null;    private $_snow=0;    private $_pixel=0;    private $_line=0;  public function __construct($config=array()){    if(is_array($config)&&count($config)>0){      if(isset($config["fontfile"])&&is_file($config["fontfile"])&&is_readable($config["fontfile"])){        $this->_fontfile=$config["fontfile"];      }else{        return false;      }      if(isset($config["size"])&&$config["size"]>0){        $this->_size=(int)$config["size"];      }      if(isset($config["width"])&&$config["width"]>0){        $this->_width=(int)$config["width"];      }      if(isset($config["height"])&&$config["height"]>0){        $this->_height=(int)$config["height"];      }      if(isset($config["length"])&&$config["length"]>0){        $this->_length=(int)$config["length"];      }      if(isset($config["snow"])&&$config["snow"]>0){        $this->_snow=(int)$config["snow"];      }      if(isset($config["pixel"])&&$config["pixel"]>0){        $this->_pixel=(int)$config["pixel"];      }      if(isset($config["line"])&&$config["line"]>0){        $this->_line=(int)$config["line"];      }      $this->_image=imagecreatetruecolor($this->_width,$this->_height);      return $this->_image;     }     else{      return false;    }  }  public function getCaptcha(){    $white=imagecolorallocate($this->_image,255,255,255);    imagefilledrectangle($this->_image,0,0,$this->_width,$this->_height,$white);    $str=$this->_generateStr($this->_length);    if(false===$str){      return false;    }    $fontfile=$this->_fontfile;    for($i=0;$i<$this->_length;$i++){      $size=$this->_size;      $angle=mt_rand(-30,30);      $x=ceil($this->_width/$this->_length)*$i+mt_rand(5,10);      $y=ceil($this->_height/1.5);      $color=$this->_getRandColor();      //针对中文字符截取      //$text=mb_substr($str,$i,1,"utf-8");      $text=$str{$i};      imagettftext($this->_image, $size, $angle, $x, $y, $color, $fontfile, $text);    }    if($this->_snow){      $this->_getSnow();    }else{      if($this->_pixel){        $this->_getPixel();      }      if($this->_line){        $this->_getLine();      }    }    header("content-type:image/png");    imagepng($this->_image);    imagedestroy($this->_image);    return strtolower($str);  }  private function _getSnow(){    for($i=1;$i<=$this->_snow;$i++){      imagestring($this->_image,mt_rand(1,5),mt_rand(0,$this->_width),mt_rand(0,$this->_height),"*",$this->_getRandColor());    }  }  private function _getPixel(){    for($i=1;$i<=$this->_pixel;$i++){      imagesetpixel($this->_image,mt_rand(0,$this->_width),mt_rand(0,$this->_height),$this->_getRandColor());    }  }  private function _getLine(){    for($i=1;$i<=$this->_line;$i++){      imageline($this->_image,mt_rand(0,$this->_width),mt_rand(0,$this->_height),mt_rand(0,$this->_width),mt_rand(0,$this->_height),$this->_getRandColor());    }  }  private function _generateStr($length=4){    if($length<1 || $length>30){      return false;    }    $chars=array(      "a","b","c","d","e","f","g","h","k","m","n","p","x","y","z",      "A","B","C","D","E","F","G","H","K","M","N","P","X","Y","Z",      1,2,3,4,5,6,7,8,9      );    $str=join("",array_rand(array_flip($chars),$length));    return $str;  }  private function _getRandColor(){    return imagecolorallocate($this->_image,mt_rand(0,255),mt_rand(0,255),mt_rand(0,255));  }}?>

 2、testCaptcha.php

<?phprequire_once "classgd.class.php";$config=array("fontfile"=>"fonts/simfang.ttf",  //引入字体文件//"snow"=>50,"pixel"=>100,"line"=>10  );$captcha=new Captcha($config);$captcha->getCaptcha();?>

总结

以上所述是小编给大家介绍的PHP实现随机数字、字母的验证码功能，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对网页设计网站的支持！