<?php
require_once?'string.func.php';
//通過GD庫做驗證碼

function?verifyImage($type=1,$length=4,$pixel=0,$line=0,$sess_name="verify"){
	session_start();
	//創建畫布
	$width=80;
	$height=28;
	$image=imagecreatetruecolor($width,$height);
	$white=imagecolorallocate($image,255,255,255);
	$black=imagecolorallocate($image,0,0,0);
	//填充矩形填充畫布
	imagefilledrectangle($image,1,1,$width-2,$height-2,$white);
	$chars=buildRandomString($type,$length);
	$_SESSION[$sess_name]=$chars;
	$fontfiles=array('msyh.ttf');
	for($i=0;$i<$length;$i++){
		$size=mt_rand(14,18);
		$angle=mt_rand(-15,15);
		$x=5+$i*$size;
		$y=mt_rand(20,26);
		$fontfile="../fonts/".$fontfiles[mt_rand(0,count($fontfiles)-1)];
		$color=imagecolorallocate($image,mt_rand(50,90),mt_rand(0,255),mt_rand(0,255));
		
		$text=substr($chars,$i,1);
		imagettftext($image,$size,$angle,$x,$y,$color,$fontfile,$text);
	}
	if($pixel){
		for($i=0;$i<50;$i++){
			imagesetpixel($image,mt_rand(0,$width-1),mt_rand(0,$height-1),$black);
		}
	}
	if($line){
		for($i=1;$i<$line;$i++){
			$color=imagecolorallocate($image,mt_rand(50,90),mt_rand(0,255),mt_rand(0,255));
			imageline($image,mt_rand(0,$width-1),mt_rand(0,$height-1),mt_rand(0,$width-1),mt_rand(0,$height-1),$color);
		}
	}
	header("content-type:image/gif");
	imagegif($image);
	imagedestroy($image);
}

<?php

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

if($type==1){

$chars=join('',range(0,9));

}elseif($type==2){

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

}elseif($type==3){

$chars=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);

return substr($chars,0,$length);

}