public static function numVerify($length = 4, $type = 'png', $width = 150, $height = 35, $verifyName = 'verifyCode', $font = 'tahoma.ttf')
{
$randNum = substr(str_shuffle(str_repeat('0123456789', 5)), 0, $length);
$authKey = md5(mt_rand() . microtime());
Cookie::set($verifyName, $authKey);
Model::getInstance()->cache()->set($authKey, $randNum, 1800);
$width = $length * 33 + 20 > $width ? $length * 33 + 20 : $width;
$height = $length < 35 ? 35 : $height;
if ($type != 'gif' && function_exists('imagecreatetruecolor')) {
$im = imagecreatetruecolor($width, $height);
} else {
$im = imagecreate($width, $height);
}
$r = array(225, 255, 255, 223);
$g = array(225, 236, 237, 255);
$b = array(225, 236, 166, 125);
$key = mt_rand(0, 3);
$backColor = imagecolorallocate($im, $r[$key], $g[$key], $b[$key]);
//背景色（随机）
$borderColor = imagecolorallocate($im, 100, 100, 100);
//边框色
imagefilledrectangle($im, 0, 0, $width - 1, $height - 1, $backColor);
imagerectangle($im, 0, 0, $width - 1, $height - 1, $borderColor);
$stringColor = imagecolorallocate($im, mt_rand(0, 200), mt_rand(0, 120), mt_rand(0, 120));
// 干扰
for ($i = 0; $i < 10; $i++) {
imagearc($im, mt_rand(-10, $width), mt_rand(-10, $height), mt_rand(30, 300), mt_rand(20, 200), 55, 44, $stringColor);
}
for ($i = 0; $i < 25; $i++) {
imagesetpixel($im, mt_rand(0, $width), mt_rand(0, $height), $stringColor);
}
for ($i = 0; $i < $length; $i++) {
$x = $i === 0 ? 15 : $i * 35;
$stringColor = imagecolorallocate($im, mt_rand(0, 200), mt_rand(0, 120), mt_rand(0, 120));
imagettftext($im, 28, mt_rand(0, 60), $x, 35, $stringColor, CML_EXTEND_PATH . DIRECTORY_SEPARATOR . $font, $randNum[$i]);
}
self::output($im, $type);
}