How to generate qrcode in the Codeigniter framework?

I call qrcode in the Controller of Codeigniter. The generated image is always broken. But it is normal in a non-Codeigniter framework. I don't know where the error is. Thank you !! The following is my code: My controller (the q_interface file is already a... can you tell me that I call qrcode in the Controller of Codeigniter, And the generated image is always broken.
But it is normal in a non-Codeigniter framework. I don't know where the error is. Thank you !!
The following is my code:

My controller (the q_interface file has been autoload ):

class Qrcode3 extends CI_Controller {    public function __construct() {        parent::__construct();    }    public function index() {        echo $this->q_interface->t("abc");    }}

Q_interface file:

... // Include the class Q_interface {public function t ($ data) {$ img = QRcode: png ($ data); $ imgData = "data: image/png; base64 ,". base64_encode ($ img); return $ imgData ;}}

Reply content:

I call qrcode in the Controller of Codeigniter. The generated image is always broken.
But it is normal in a non-Codeigniter framework. I don't know where the error is. Thank you !!
The following is my code:

My controller (the q_interface file has been autoload ):

class Qrcode3 extends CI_Controller {    public function __construct() {        parent::__construct();    }    public function index() {        echo $this->q_interface->t("abc");    }}

Q_interface file:

... // Include the class Q_interface {public function t ($ data) {$ img = QRcode: png ($ data); $ imgData = "data: image/png; base64 ,". base64_encode ($ img); return $ imgData ;}}