<?php

Class Captcha{

//字體文件

private $_fontfile='';

//字體大小

private $_size=20;

//寬度

private $_width=200;

//高度

private $_height=50;

//驗證碼長度

private $_length=4;

//畫布資源

private $_image=null;

//干擾元素

//雪花*的個數

private $_snow=0;

//像素個數

private $_pixel=0;

//線段個數

private $_line=0;

? ? //初始化數據

public function _construct($config=array()){

if(is_array($config)&&count($config)>0){

? ?//檢測字體文件是否存在并且可讀

if(isset($config['fontfile'])&&is_file($config['fontfile'])&&is_readable($config['fontfile'])){

$this->_fontfile=$config['fontfile'];

}else{

return false;

? ? }

? ? //檢測是否設置畫布寬或高

? ? if(isset($config['width'])&&$config['width']>0){

? ? $this->_width=(int)$config['width'];

? ? }

? ? if(isset($config['height'])&&$config['height']>0){

? ? $this->_height=(int)$config['height'];

? ? }

? ? //檢測是否設置字體大小

? ? if(isset($config['size'])&&$config['size']>0){

? ? $this->_size=(int)$config['size'];

? ? }

? ? //檢測是否設置驗證碼長度

? ? if(isset($config['length'])&&$config['length']>0){

? ? $this->_length=(int)$config['length'];

? ? }

? ? //配置干擾元素

? ? 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);

//填充矩形

imagefilledrectangle($this->_image,0,0,$this->_width,$this->_height,$white);

//生成驗證碼

$str=$this->_generateStr($this->_length);

if($str==false){

return false;

}

$fontfile=$this->_fontfile;

//繪制驗證碼

for($i=0;$i<$this->_length;$i++){

$size=$this->_size;

$angle=mt_rand(-15,15);

$x=ceil($this->_width/$this->_length)*$i+mt_rand(5,10);

$y=ceil($this->_height/1.5);

$color=$this->_getRandColor();

//$text=mb_substr($str,$i,1,'utf-8');

$text=$str{$i};

imagettftext($this->_image,$size, $angle, $x, $y, $color, $fontfile, $text);

}

//產生干擾元素

if($this->_snow){

//使用雪花當干擾元素

$this->_getSnow();

}else{

if($this->_pixel){

$this->_getPixel();

}

if($this->_line){

$this->_getLine();

}

}

//輸出圖像

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());

}

}

? ?

//產生驗證碼字符

private function _generateStr($length=4){

if($length<1 || $length>10){

return false;

}

$chars=array(

'a','b','c','d','e','f','g','h','k','m','n','p','x','y',

'A','B','C','D','E','F','G','H','K','M','N','P','X','Y',

1,2,3,4,5,6,7,8,9

? ? ? ? ? ? );

$str=join('',array_rand(array_flip($chars),$length));

return $str;

}

//產生隨機顏色

private function _getRandColor(){

? ? ?return imagecolorallocate($this->_image,mt_rand(0,255),mt_rand(0,255),mt_rand(0,255));

}

}