如何使用PHPMailer将QRCode发送到Gmail (CodeIgniter 3)

<?php
defined('BASEPATH') OR exit('No direct script access allowed');

require_once APPPATH.'libraries/PHPMailer/PHPMailerAutoload.php';

class Email extends PHPMailer {

    public function __construct($exceptions = null) {
        parent::__construct($exceptions);
    }

}

$config['protocol'] = 'smtp';
$config['smtp_host'] = 'smtp.gmail.com';
$config['smtp_port'] = 587;
$config['smtp_user'] = 'your_email@gmail.com';
$config['smtp_pass'] = 'your_password';
$config['smtp_crypto'] = 'tls';
$config['mailtype'] = 'html';
$config['charset'] = 'utf-8';
$config['newline'] = "\r\n";

<?php
defined('BASEPATH') OR exit('No direct script access allowed');

class Qrcode extends CI_Controller {

    public function __construct() {
        parent::__construct();
        $this->load->library('email');
    }

    public function index() {
        // 生成QRCode图片
        $qrcode = 'path_to_qrcode.png'; // 替换为你的QRCode图片路径

        // 发送邮件
        $this->email->from('your_email@gmail.com', 'Your Name');
        $this->email->to('recipient_email@gmail.com');
        $this->email->subject('QRCode');
        $this->email->message('Please find the attached QRCode.');
        $this->email->attach($qrcode);

        if ($this->email->send()) {
            echo 'Email sent successfully.';
        } else {
            echo 'Email sending failed.';
        }
    }

}