custom barcode plugin

Im trying to write a barcode plugin follow instructions from
https://xlinesoft.com/phprunner/docs/how_to_create_a_custom_edit_control.htm
But when i run application i receive the message
Fatal error: Call to undefined method ViewBarCode::addJSSetting() in E:\xampp\htdocs\barcodedemo\classes\controls\Viewbarcode.php on line 13
What im missing?

The Viewbarcode.php starts with

<?php

class ViewBarCode extends ViewUserControl

{

public function initUserControl()

{

//

$this->output="canvas";

$this->type="ean13";

//

if ($this->settings["output"]) $this->output=$this->settings["output"];

if ($this->settings["type"]) $this->type=$this->settings["type"];

//

$this->addJSSetting("output", $this->output);

$this->addJSSetting("type", $this->type);