How do I get the current window width and window size?

[Guelakais]

Unless otherwise specified, bevy sets the window size itself. I wanted to access exactly these values in my setup and update methods, as in the following example:

fn setup_instructions(mut commands: Commands,windows: WindowResolution) {
    commands.spawn(
        TextBundle::from_section("", TextStyle::default()).with_style(Style {
            position_type: PositionType::Absolute,
            top: Val::Px(12.0*windows.height()),
            left: Val::Px(12.0*windows.width()),
            ..default()
        }),
    );
}

How do you get it right?

[Fidius-jko]

fn toggle_resolution(
    mut windows: Query<&mut Window>,
) {
    let mut window = windows.single_mut(); // Get window
    println!(window.resolution.width(), window.resolution.height());
}

[Guelakais]

Almost. I have now found out how to integrate it correctly:

The setup method in which the text now behaves in relation to the window width:

fn setup_instructions(mut commands: Commands, windows: Query<&mut Window>) {
    commands.spawn(
        TextBundle::from_section("", TextStyle::default()).with_style(Style {
            position_type: PositionType::Absolute,
            top: Val::Px(12.0/windows.single().resolution.height()),
            left: Val::Px(12.0/windows.single().resolution.width()),
            ..default()
        }),
    );
}

Ai circles, which no longer disappear from the playing field:

fn calculate_translation(border: f32, current_number: f32, mut rng: ThreadRng) -> f32 {
    if current_number >= border/2.0{
        current_number-rng.gen_range(0.0..40.0)
    } else if current_number <= -border/2.0{
        current_number+rng.gen_range(0.0..40.0)
    } else {
        current_number+rng.gen_range(-40.0..40.0)
    }
}
fn move_entity(mut transforms: Query<&mut Transform, With<Entity>>,windows: Query<&mut Window>) {
    let rng = rand::thread_rng();
    transforms.iter_mut().for_each(|mut transform| {
        transform.translation.x =
            calculate_translation(windows.single().resolution.width(), transform.translation.x, rng.clone());
        transform.translation.y =
            calculate_translation(windows.single().resolution.height(), transform.translation.y, rng.clone());
    });
}

[rparrett]

You may be able to use Val::Percent or Val::Vh / Val::Vw in the UI scenario.

And for your circles, keep in mind that if you've translated or zoomed your camera, the window resolution won't necessary match up with the camera's viewport.

[Guelakais]

gI take a more dignified approach. I've just managed to move my text fields freely on the screen and assign randomly generated colours to my entities. I'll get back to you when I understand what you mean. ;)