<?php



//生成验证码图片

Header("Content-type: image/PNG");

srand((double)microtime()*1000000);

$im = imagecreate(62,20);

$black = ImageColorAllocate($im, 0,0,0);

$white = ImageColorAllocate($im, 255,255,255);

$gray = ImageColorAllocate($im, 200,200,200);

imagefill($im,68,30,$gray);

while(($authnum=rand()%100000)<10000);

setcookie("login_check_number",$authnum,time()+3600*24*0.1,'/');



//将四位整数验证码绘入图片

imagestring($im, 5, 10, 3, $authnum, $white);

for($i=0;$i<200;$i++) //加入干扰象素

{

$randcolor = ImageColorallocate($im,rand(0,255),rand(0,255),rand(0,255));

imagesetpixel($im, rand()%70 , rand()%30 , $randcolor);

}
ImagePNG($im);
ImageDestroy($im);
?>
