/**
 *微信接口调用凭证
 */
public function checkAuth($appid, $appsecret)
{
    $url = 'https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=' . $appid . '&secret=' . $appsecret;
    $result = $this->httpRequest($url);
    if ($result) {
        $json = json_decode($result, true);
        if (!$json || isset($json['errcode'])) {
            return false;
        }
        return $json['access_token'];
    }
    return false;

}

/**
 * 小程序二维码
 */
public function Wxcode($openid)
{
    $appsecret = preg_replace("/\s/", "",*******);
    $appid = *******;
    $token = $this->checkAuth($appid, $appsecret);
    $url = "https://api.weixin.qq.com/wxa/getwxacodeunlimit?access_token=" . $token;
    $post_data = json_encode([
        'page' => 'pages/index/index',
        'width' => 1280,
        'scene' => $openid,
    ]);
    $data = $this->httpRequest($url, $post_data, 'POST');
    $poster = './upload/poster/posters.jpg';   //海报
    $result = $this->poster($data, $poster, $openid);
    return json(['code' => 1, 'msg' => 'succeed', 'data' => "http://" . $_SERVER['HTTP_HOST'] . $result]);
}

/**
 * 合成海报二维码
 */
function poster($code, $poster, $openid)
{
    $timg = imagecreatefromstring(file_get_contents($poster));        //目标图象连接资源。
    $originalUrl = imagecreatefromstring($code);    //源图象连接资源。
    $QR_width1 = imagesx($timg);            //背景海报图片宽度
    $QR_height1 = imagesy($timg);            //背景海报图片高度
    $logo_width1 = imagesx($originalUrl);        //logo图片宽度
    $logo_height1 = imagesy($originalUrl);        //logo图片高度
    $logo_qr_width1 = $QR_width1 / 4;       //组合之后logo的宽度(占二维码的1/5)
    $scale1 = $logo_width1 / $logo_qr_width1;       //logo的宽度缩放比(本身宽度/组合后的宽度)
    $logo_qr_height1 = $logo_height1 / $scale1;  //组合之后logo的高度
    $from_width1 = ($QR_width1 - $logo_qr_width1) / 2;   //组合之后logo左上角所在坐标点
    //重新组合图片并调整大小
    //imagecopyresampled() 将一幅图像(源图象)中的一块正方形区域拷贝到另一个图像中
    imagecopyresampled($timg,
        $originalUrl,
        $from_width1,
        $from_width1 * 1.8,
        0,
        0,
        $logo_qr_width1,
        $logo_qr_height1,
        $logo_width1,
        $logo_height1
    );
    $filename = './upload/code/' . $openid . '.jpg';
    //输出图片
    imagepng($timg, $filename);

    return $filename;
}

/**
 * @param $url
 * @param string $data
 * @param string $method
 * @return bool|string
 */
function httpRequest($url, $data = '', $method = 'GET')
{
    $curl = curl_init();
    curl_setopt($curl, CURLOPT_URL, $url);
    curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, 0);
    curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, 0);
    curl_setopt($curl, CURLOPT_USERAGENT, $_SERVER['HTTP_USER_AGENT']);
    curl_setopt($curl, CURLOPT_FOLLOWLOCATION, 1);
    curl_setopt($curl, CURLOPT_AUTOREFERER, 1);
    if ($method == 'POST') {
        curl_setopt($curl, CURLOPT_POST, 1);
        if ($data != '') {
            curl_setopt($curl, CURLOPT_POSTFIELDS, $data);
        }
    }

    curl_setopt($curl, CURLOPT_TIMEOUT, 30);
    curl_setopt($curl, CURLOPT_HEADER, 0);
    curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
    $result = curl_exec($curl);
    curl_close($curl);
    return $result;
}