有谁帮忙把php的验证码代码修改一下。
验证码中的字和$_SESSION['code']中的值不一致！
谢谢了！

<?php
class Imagecode{
private $width ;
private $height;
private $counts;
private $distrubcode;
private $fonturl;
private $session;
function __construct($width = 120,$height = 30,$counts = 5,$distrubcode="1235467890qwertyuipkjhgfdaszxcvbnm",$fonturl="./TektonPro-BoldCond.otf"){
$this->width=$width;
$this->height=$height;
$this->counts=$counts;
$this->distrubcode=$distrubcode;
$this->fonturl=$fonturl;
$this->session=$this->sessioncode();
session_start();
$_SESSION['code']=$this->session;
}
function imageout(){
$im=$this->createimagesource();
$this->setbackgroundcolor($im);
$this->set_code($im);
$this->setdistrubecode($im);
ImageGIF($im);
ImageDestroy($im); 
}
private function createimagesource(){
return imagecreate($this->width,$this->height);
}
private function setbackgroundcolor($im){
$bgcolor = ImageColorAllocate($im, rand(200,255),rand(200,255),rand(200,255));
imagefill($im,0,0,$bgcolor);
}
private function setdistrubecode($im){
$count_h=$this->height;
$cou=floor($count_h*2);
for($i=0;$i<$cou;$i++){
$x=rand(0,$this->width);
$y=rand(0,$this->height);
$jiaodu=rand(0,360);
$fontsize=rand(8,15);
$fonturl=$this->fonturl;
$originalcode = $this->distrubcode;
$countdistrub = strlen($originalcode);
$dscode = $originalcode[rand(0,$countdistrub-1)];
$color = ImageColorAllocate($im, rand(40,140),rand(40,140),rand(40,140));
imagettftext($im,$fontsize,$jiaodu,$x,$y,$color,$fonturl,$dscode);
}
}
private function set_code($im){
$width=$this->width;
$counts=$this->counts;
$height=$this->height;
$scode=$this->session;
$y=floor($height/2)+floor($height/4);
$fontsize=rand(30,35);
$fonturl="./AdobeGothicStd-Bold.otf";
$counts=$this->counts;
for($i=0;$i<$counts;$i++){
$char=$scode[$i];
$x=floor($width/$counts)*$i+8;
$jiaodu=rand(-20,30);
$color = ImageColorAllocate($im,rand(0,50),rand(50,100),rand(100,140));
imagettftext($im,$fontsize,$jiaodu,$x,$y,$color,$fonturl,$char);
}
}
private function sessioncode(){
$originalcode = $this->distrubcode;
$countdistrub = strlen($originalcode);
$_dscode = "";
$counts=$this->counts;
for($j=0;$j<$counts;$j++){
$dscode = $originalcode[rand(0,$countdistrub-1)];
$_dscode.=$dscode;
}
return $_dscode;
}
}
Header("Content-type: image/GIF");
$imagecode=new  Imagecode(160,50);
echo $imagecode->imageout();
?>