#!/usr/bin/gjs

imports.gi.versions.Gtk = '3.0';

const GObject = imports.gi.GObject;

const Gtk = imports.gi.Gtk;

class ScrolledWindowExample {

    // Create the application itself

    constructor() {

        this.application = new Gtk.Application({

            application_id: 'org.example.jscrolledwindow'

        });

        // Connect 'activate' and 'startup' signals to the callback functions

        this.application.connect('activate', this._onActivate.bind(this));

        this.application.connect('startup', this._onStartup.bind(this));

    }

    // Callback function for 'activate' signal presents windows when active

    _onActivate() {

        this.window.present();

    }

    // Callback function for 'startup' signal builds the UI

    _onStartup() {

        this._buildUI();

    }

    // Build the application's UI

    _buildUI() {

        // Create the application window

        this.window = new Gtk.ApplicationWindow({

            application: this.application,

            window_position: Gtk.WindowPosition.CENTER,

            title: "ScrolledWindow Example",

            default_width: 200,

            default_height: 200,

            border_width: 10

        });

        // the scrolledwindow

        this.scrolledWindow = new Gtk.ScrolledWindow();

        this.scrolledWindow.set_border_width(10);

        // there is always the scrollbar (otherwise: AUTOMATIC - only if needed - or NEVER)

        this.scrolledWindow.set_policy(Gtk.PolicyType.ALWAYS, Gtk.PolicyType.ALWAYS);

        // an image - slightly larger than the window

        this.image = new Gtk.Image();

        this.image.set_from_file("gnome-image.png");

        // add the image to the scrolledwindow

        this.scrolledWindow.add_with_viewport(this.image);

        // add the scrolledwindow to the window

        this.window.add(this.scrolledWindow);

        this.window.show_all();

    }

};

// Run the application

let app = new ScrolledWindowExample();

app.application.run (ARGV);