黑色背景中间白框，没有显示验证码，弄了一天了，求解救
<?php
/**
* Created by PhpStorm.
* User: a117
* Date: 2018/10/14
* Time: 5:45 PM
*/
require_once 'string.func.php';
//创建画布，GD库做验证码
$width=80;
$height=30;
$image=imagecreatetruecolor($width,$height);
$white=imagecolorallocate($image,255,255,255);
$black=imagecolorallocate($image,0,0,0);
//填充画布，填充矩形
imagefilledrectangle($image,1,1,$width-2,$height-2,$white);
$type=1;
$length=4;
$chars=buildRandomString($type,$length);
//比对验证码
$sess_name="verify";
$_SESSION[$sess_name]=$chars;
//字体数组
$fontfile=array("Avenir.ttc","Helvetica.ttc","Kohinoor.ttc");
//产生验证码
for ($i=9;$i<$length;$i++){
$size=mt_rand(14,18);
$angle=mt_rand(-15,15);
$x=5+$i*$size;
$y=mt_rand(20,26);
$fontfile="../fonts/".$fontfile[mt_rand(0,count($fontfile)-1)];
$color=imagecolorallocate($image,mt_rand(50,90),mt_rand(80,200),mt_rand(90,180));
//截取验证码
$text=substr($chars,$i,1);
imagettftext($image,$size,$angle,$x,$y,$color,$fontfile,$text);
}
header("content-type:image/gif");
imagegif($image);
imagedestroy($image);下面是string.func.php的
<?php
/**
* Created by PhpStorm.
* User: a117
* Date: 2018/10/14
* Time: 5:46 PM
*/
function buildRandomString($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("字符串长度不够");
}
$chars = str_shuffle($chars);
//截取验证码长度
return substr($chars, 0, $length);
}GD库应该开了
