window_resizing/
window_resizing.rs

1//! This example illustrates how to resize windows, and how to respond to a window being resized.
2use bevy::{prelude::*, window::WindowResized};
3
4fn main() {
5    App::new()
6        .insert_resource(ResolutionSettings {
7            large: Vec2::new(1920.0, 1080.0),
8            medium: Vec2::new(800.0, 600.0),
9            small: Vec2::new(640.0, 360.0),
10        })
11        .add_plugins(DefaultPlugins)
12        .add_systems(Startup, (setup_camera, setup_ui))
13        .add_systems(Update, (on_resize_system, toggle_resolution))
14        .run();
15}
16
17/// Marker component for the text that displays the current resolution.
18#[derive(Component)]
19struct ResolutionText;
20
21/// Stores the various window-resolutions we can select between.
22#[derive(Resource)]
23struct ResolutionSettings {
24    large: Vec2,
25    medium: Vec2,
26    small: Vec2,
27}
28
29// Spawns the camera that draws UI
30fn setup_camera(mut commands: Commands) {
31    commands.spawn(Camera2d);
32}
33
34// Spawns the UI
35fn setup_ui(mut commands: Commands) {
36    // Node that fills entire background
37    commands
38        .spawn(Node {
39            width: percent(100),
40            ..default()
41        })
42        // Text where we display current resolution
43        .with_child((
44            Text::new("Resolution"),
45            TextFont {
46                font_size: 42.0,
47                ..default()
48            },
49            ResolutionText,
50        ));
51}
52
53/// This system shows how to request the window to a new resolution
54fn toggle_resolution(
55    keys: Res<ButtonInput<KeyCode>>,
56    mut window: Single<&mut Window>,
57    resolution: Res<ResolutionSettings>,
58) {
59    if keys.just_pressed(KeyCode::Digit1) {
60        let res = resolution.small;
61        window.resolution.set(res.x, res.y);
62    }
63    if keys.just_pressed(KeyCode::Digit2) {
64        let res = resolution.medium;
65        window.resolution.set(res.x, res.y);
66    }
67    if keys.just_pressed(KeyCode::Digit3) {
68        let res = resolution.large;
69        window.resolution.set(res.x, res.y);
70    }
71}
72
73/// This system shows how to respond to a window being resized.
74/// Whenever the window is resized, the text will update with the new resolution.
75fn on_resize_system(
76    mut text: Single<&mut Text, With<ResolutionText>>,
77    mut resize_reader: MessageReader<WindowResized>,
78) {
79    for e in resize_reader.read() {
80        // When resolution is being changed
81        text.0 = format!("{:.1} x {:.1}", e.width, e.height);
82    }
83}
window_resizing/window_resizing.rs

window_resizing/
window_resizing.rs
