How, with Bevy, can you get and set Window information after creation?

Question

I want to be able to read and set window-settings with Bevy. I attempted to do so with a basic system:

fn test_system(mut win_desc: ResMut<WindowDescriptor>) {
    win_desc.title = "test".to_string();
    println!("{}",win_desc.title);
}

While this works (partially), it only gives you the original settings, and it doesn't allow changes at all. In this example, the title will not change, but the display of the title will. In another example, changing the window-size (manually at run-time) will not be reflected if you were to print win_desc.width.

score 9 · Accepted Answer · answered Aug 31 '20 at 07:07

At the moment, the WindowDescriptor is used only during window creation and is not updated later

To get notified when the window is resized I use this system:

fn resize_notificator(resize_event: Res<Events<WindowResized>>) {
    let mut reader = resize_event.get_reader();
    for e in reader.iter(&resize_event) {
        println!("width = {} height = {}", e.width, e.height);
    }
}

Other useful events can be found at https://github.com/bevyengine/bevy/blob/master/crates/bevy_window/src/event.rs

Does this mean that currently we cannot resize the window? – STF_ZBR Aug 31 '20 at 22:02 — STF_ZBR, Aug 31 '20 at 22:02

score 6 · Answer 2 · answered Dec 07 '20 at 03:05

There's a nice example of working with windows provided in the bevy GitHub repo: https://github.com/bevyengine/bevy/blob/master/examples/window/window_settings.rs

For your case of reading / writing window size:

fn window_resize_system(mut windows: ResMut<Windows>) {
    let window = windows.get_primary_mut().unwrap();
    println!("Window size was: {},{}", window.width(), window.height());
    window.set_resolution(1280, 720);
}

As zyrg mentioned, you can also listen for window events.

score 4 · Answer 3 · answered Jul 08 '23 at 16:13

With Bevy 0.10 you can do this:

fn get_window(window: Query<&Window>) {
    let window = window.single();

    let width = window.resolution.width();
    let height = window.resolution.height();

    let (x, y) = match window.position {
        WindowPosition::At(v) => (v.x as f32, v.y as f32),
        _ => (0., 0.),
    };

    dbg!(width, height, x, y);
}

How, with Bevy, can you get and set Window information after creation?

3 Answers3