008-php generates random verification code

This article introduces the random verification code generated by php. Now I share it with everyone. Friends in need can refer to it

<?php 

/**
* 生成随机字符串
* @param int $num 生成的随机字符串的个数
* @return str 生成的随机字符串
*/
function randStr($num=6) {
	$str = str_shuffle(&#39;abcedfghjkmnpqrstuvwxyzABCEDFGHJKMNPQRSTUVWXYZ23456789&#39;);
	return substr($str, 0 , $num);
}

//1.创建画布
$pic = imagecreatetruecolor(80, 50);

//2.创建颜料（RGB）
$red = imagecolorallocate($pic, 255, 0, 0);
$blue = imagecolorallocate($pic, 127, 127, 127);

//3.背景填充
imagefill($pic, 0, 0, $red);

//4.写入文字
imagestring($pic, 5, 5, 5, randStr(4), $blue);

//5. 输出/保存图形
header(&#39;Content-type:image/png&#39;);
imagepng($pic);

//6. 销毁画布(关闭画板)
imagedestroy($pic);

?>

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