PHP generates verification codes with specified digits and controllable interference elements

	//range('a','z')将括号中的内容作为键值生成一个索引数组
	//array_merge($array1,$array2)合并两个数组中的键值，生成新索引数组
	//array_flip()将括号中的内容，键名与键值对换
	//array_rand($array,$length)随机取出$array中$length长度的键名作为新数组的键值，生成一个索引数组
	//join('',$array)以空连接数组中的值，以数组的内容生成字符串

<?php
function buildVerifyCode($type=2,$length=4){
switch ($type) {
	case 0:
	$string=join(&#39;&#39;,array_rand(range(0,9),$length));
	break;
	case 1:
	$string=join(&#39;&#39;,array_rand(array_flip(array_merge(range(&#39;a&#39;,&#39;z&#39;),range(&#39;A&#39;,&#39;Z&#39;))),$length));
	break;
	case 2:
	$string=join(&#39;&#39;,array_rand(array_flip(array_merge(range(&#39;a&#39;,&#39;z&#39;),range(&#39;A&#39;,&#39;Z&#39;),range(0,9))),$length));
	break;
}
return $string;
}

<?php
require &#39;buildVerifyCode.func.php&#39;;
echo buildVerifyCode();
// 	$fontfiles=[&#39;msyh.ttc&#39;,&#39;msyhbd.ttc&#39;,&#39;msyhl.ttc&#39;,&#39;simsun.ttc&#39;,&#39;Sitka.ttc&#39;];
// 	$fontfile=$fontfiles[mt_rand(0,count($fontfiles)-1)];
// var_dump($fontfile);

<?php
$width=100;
$height=30;
//创建画布，默认底色黑色，rgb0，0，0
$image=imagecreatetruecolor($width,$height);
//创建白色，方便覆盖画布
$white=imagecolorallocate($image,255,255,255);
//创建白色矩形覆盖原始画布
imagefilledrectangle($image,1,1,$width-2,$height-2,$white);
require &#39;buildVerifyCode.func.php&#39;;
$type=2;
$length=4;
$verifyCode=buildVerifyCode($type,$length);
for($i=0;$i<$length;$i++){
	$color=imagecolorallocate($image,mt_rand(50,90),mt_rand(80,200),mt_rand(90,150));
	$size=mt_rand(14,16);
	$angle=mt_rand(-15,15);
	$x=($i*100/5)+$size;
	$y=mt_rand(20,25);
	$fontfiles=[&#39;msyh.ttc&#39;,&#39;msyhbd.ttc&#39;,&#39;msyhl.ttc&#39;,&#39;simsun.ttc&#39;,&#39;Sitka.ttc&#39;];
	$fontfile="../fonts/".$fontfiles[mt_rand(0,count($fontfiles)-1)];
	$text=substr($verifyCode,$i,1);
	imagettftext($image,$size,$angle,$x,$y,$color,$fontfile,$text);
}
$pixel=120;
if($pixel){
	$pixelcolor=imagecolorallocate($image,mt_rand(150,170),mt_rand(100,140),mt_rand(90,160));
	for($i=0;$i<$pixel;$i++){
		imagesetpixel($image,mt_rand(0,$width-1),mt_rand(0,$height-1),$pixelcolor);
	}
}
$line=4;
if($line){
	for($i=0;$i<$line;$i++){
		imageline($image,mt_rand(0,$width-1),mt_rand(0,$height-1),mt_rand(0,$width-1),mt_rand(0,$height-1),$pixelcolor);
	}
}

header(&#39;content-type:image/png&#39;);
imagepng($image);
imagedestroy($image);