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
rush:PHP;">
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);
imagefilledrectangle($this->_image,$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),$this->_height),'*',$this->_getRandColor());
}
}
private function _getPixel(){
for($i=1;$i<=$this->_pixel;$i++){
imagesetpixel($this->_image,$this->_getRandColor());
}
}
private function _getLine(){
for($i=1;$i<=$this->_line;$i++){
imageline($this->_image,$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',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,255),255));
}
}
?>
2、testCaptcha.PHP
rush:PHP;">
'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。程序员遇到问题都会上（编程之家jb51.cc）查找问题解答方法！如果觉得站点还不错，随手转发给程序员朋友一下！
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