bevy/examples/window/window_resizing.rs
Aceeri ddfafab971 Windows as Entities (#5589)
# Objective

Fix https://github.com/bevyengine/bevy/issues/4530

- Make it easier to open/close/modify windows by setting them up as `Entity`s with a `Window` component.
- Make multiple windows very simple to set up. (just add a `Window` component to an entity and it should open)

## Solution

- Move all properties of window descriptor to ~components~ a component.
- Replace `WindowId` with `Entity`.
- ~Use change detection for components to update backend rather than events/commands. (The `CursorMoved`/`WindowResized`/... events are kept for user convenience.~
  Check each field individually to see what we need to update, events are still kept for user convenience.

---

## Changelog

- `WindowDescriptor` renamed to `Window`.
    - Width/height consolidated into a `WindowResolution` component.
    - Requesting maximization/minimization is done on the [`Window::state`] field.
- `WindowId` is now `Entity`.

## Migration Guide

- Replace `WindowDescriptor` with `Window`.
    - Change `width` and `height` fields in a `WindowResolution`, either by doing
      ```rust
      WindowResolution::new(width, height) // Explicitly
      // or using From<_> for tuples for convenience
      (1920., 1080.).into()
      ```
- Replace any `WindowCommand` code to just modify the `Window`'s fields directly  and creating/closing windows is now by spawning/despawning an entity with a `Window` component like so:
  ```rust
  let window = commands.spawn(Window { ... }).id(); // open window
  commands.entity(window).despawn(); // close window
  ```

## Unresolved
- ~How do we tell when a window is minimized by a user?~
  ~Currently using the `Resize(0, 0)` as an indicator of minimization.~
  No longer attempting to tell given how finnicky this was across platforms, now the user can only request that a window be maximized/minimized.
  
 ## Future work
 - Move `exit_on_close` functionality out from windowing and into app(?)
 - https://github.com/bevyengine/bevy/issues/5621
 - https://github.com/bevyengine/bevy/issues/7099
 - https://github.com/bevyengine/bevy/issues/7098


Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2023-01-19 00:38:28 +00:00

95 lines
2.8 KiB
Rust

///! This example illustrates how to resize windows, and how to respond to a window being resized.
use bevy::{prelude::*, window::WindowResized};
fn main() {
App::new()
.insert_resource(ResolutionSettings {
large: Vec2::new(1920.0, 1080.0),
medium: Vec2::new(800.0, 600.0),
small: Vec2::new(640.0, 360.0),
})
.add_plugins(DefaultPlugins)
.add_startup_system(setup_camera)
.add_startup_system(setup_ui)
.add_system(on_resize_system)
.add_system(toggle_resolution)
.run();
}
/// Marker component for the text that displays the current reslution.
#[derive(Component)]
struct ResolutionText;
/// Stores the various window-resolutions we can select between.
#[derive(Resource)]
struct ResolutionSettings {
large: Vec2,
medium: Vec2,
small: Vec2,
}
// Spawns the camera that draws UI
fn setup_camera(mut cmd: Commands) {
cmd.spawn(Camera2dBundle::default());
}
// Spawns the UI
fn setup_ui(mut cmd: Commands, asset_server: Res<AssetServer>) {
// Node that fills entire background
cmd.spawn(NodeBundle {
style: Style {
size: Size::new(Val::Percent(100.0), Val::Percent(100.0)),
..default()
},
..default()
})
.with_children(|root| {
// Text where we display current resolution
root.spawn((
TextBundle::from_section(
"Resolution",
TextStyle {
font: asset_server.load("fonts/FiraMono-Medium.ttf"),
font_size: 50.0,
color: Color::BLACK,
},
),
ResolutionText,
));
});
}
/// This system shows how to request the window to a new resolution
fn toggle_resolution(
keys: Res<Input<KeyCode>>,
mut windows: Query<&mut Window>,
resolution: Res<ResolutionSettings>,
) {
let mut window = windows.single_mut();
if keys.just_pressed(KeyCode::Key1) {
let res = resolution.small;
window.resolution.set(res.x, res.y);
}
if keys.just_pressed(KeyCode::Key2) {
let res = resolution.medium;
window.resolution.set(res.x, res.y);
}
if keys.just_pressed(KeyCode::Key3) {
let res = resolution.large;
window.resolution.set(res.x, res.y);
}
}
/// This system shows how to respond to a window being resized.
/// Whenever the window is resized, the text will update with the new resolution.
fn on_resize_system(
mut q: Query<&mut Text, With<ResolutionText>>,
mut resize_reader: EventReader<WindowResized>,
) {
let mut text = q.single_mut();
for e in resize_reader.iter() {
// When resolution is being changed
text.sections[0].value = format!("{:.1} x {:.1}", e.width, e.height);
}
}