<?php

require_once'string.func.php';

//通過GD庫做驗證碼

//創建畫布

$width=80;

$height=28;

$image=imagecreatetruecolor($width,$height);

$white=imagecolorallocate($image,255,255,255);

$black=imagecolorallocate($image,0,0,0);

//用填充矩形填充畫布

imagefilledrectangle($image,1,1,$width-x,$height-2,$white);

$type=1;

$length=4;

//賦值產生的驗證碼

$chars=buildRandomString($type,$length);

$_SESSION[$sess_name]=$chars;

$fontfiles= array ("simfang.ttf","simhei.ttf","simkai.ttf");

for ($i=0;$i<$length;$i++){

? ?//設置隨機大小

? ?$size=mt_rand(14,18);

? ?//隨機角度

? ?$angle=mt_rand(-15,15);

? ?$x=5+$i*$size;

? ?//隨機的Y坐標

? ?$y=mt_rand(20,26);

? ?$fontfile="../fonts/".$fontfiles[mt_rand(0,count($fontfiles)-1)];

? ?$color=imagecolorallocate($image,mt_rand(50,90),mt_rand(80,200),mt_rand(90,180));

? ?$text=substr($chars,$i,1);

? ?imagettftext($image,$size,$angle,$x,$y,$color,$fontfile,$text);

}

header("content-type:image/gif");

imagegif($image);

imagedestroy($image);

?>

string.func.php

<?php

//產生隨機的字符串

function buildRandomString($type=1,$length=4){

//$type=1;

//$length=4;

if($type==1){

? ?$char=join("",range(0,9));

}

else if($type==2){

? ?$char=join("",array_merge(range("a","z"),range("A","Z")));

}

elseif($type==3){

? ? $char=join("",array_merge(range("a","z"),range("A","Z"),range(0,9)));

}

if($length>strlen($chars)){

? ?exit("字符串長度不夠");

}

$chars=str_shuffle($chars);//隨機打亂字符串

return substr($chars,0,$length);//截取

}

?>