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

<?php
Class 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

<?php
require_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脚本之家网站的支持！