# Objective Continue improving the user experience of our UI Node API in the direction specified by [Bevy's Next Generation Scene / UI System](https://github.com/bevyengine/bevy/discussions/14437) ## Solution As specified in the document above, merge `Style` fields into `Node`, and move "computed Node fields" into `ComputedNode` (I chose this name over something like `ComputedNodeLayout` because it currently contains more than just layout info. If we want to break this up / rename these concepts, lets do that in a separate PR). `Style` has been removed. This accomplishes a number of goals: ## Ergonomics wins Specifying both `Node` and `Style` is now no longer required for non-default styles Before: ```rust commands.spawn(( Node::default(), Style { width: Val::Px(100.), ..default() }, )); ``` After: ```rust commands.spawn(Node { width: Val::Px(100.), ..default() }); ``` ## Conceptual clarity `Style` was never a comprehensive "style sheet". It only defined "core" style properties that all `Nodes` shared. Any "styled property" that couldn't fit that mold had to be in a separate component. A "real" style system would style properties _across_ components (`Node`, `Button`, etc). We have plans to build a true style system (see the doc linked above). By moving the `Style` fields to `Node`, we fully embrace `Node` as the driving concept and remove the "style system" confusion. ## Next Steps * Consider identifying and splitting out "style properties that aren't core to Node". This should not happen for Bevy 0.15. --- ## Migration Guide Move any fields set on `Style` into `Node` and replace all `Style` component usage with `Node`. Before: ```rust commands.spawn(( Node::default(), Style { width: Val::Px(100.), ..default() }, )); ``` After: ```rust commands.spawn(Node { width: Val::Px(100.), ..default() }); ``` For any usage of the "computed node properties" that used to live on `Node`, use `ComputedNode` instead: Before: ```rust fn system(nodes: Query<&Node>) { for node in &nodes { let computed_size = node.size(); } } ``` After: ```rust fn system(computed_nodes: Query<&ComputedNode>) { for computed_node in &computed_nodes { let computed_size = computed_node.size(); } } ```
		
			
				
	
	
		
			84 lines
		
	
	
		
			2.4 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
			
		
		
	
	
			84 lines
		
	
	
		
			2.4 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
//! This example illustrates how to resize windows, and how to respond to a window being resized.
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use bevy::{prelude::*, window::WindowResized};
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fn main() {
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    App::new()
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        .insert_resource(ResolutionSettings {
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            large: Vec2::new(1920.0, 1080.0),
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            medium: Vec2::new(800.0, 600.0),
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            small: Vec2::new(640.0, 360.0),
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        })
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        .add_plugins(DefaultPlugins)
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        .add_systems(Startup, (setup_camera, setup_ui))
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        .add_systems(Update, (on_resize_system, toggle_resolution))
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        .run();
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}
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/// Marker component for the text that displays the current resolution.
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#[derive(Component)]
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struct ResolutionText;
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/// Stores the various window-resolutions we can select between.
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#[derive(Resource)]
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struct ResolutionSettings {
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    large: Vec2,
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    medium: Vec2,
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    small: Vec2,
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}
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// Spawns the camera that draws UI
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fn setup_camera(mut commands: Commands) {
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    commands.spawn(Camera2d);
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}
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// Spawns the UI
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fn setup_ui(mut commands: Commands) {
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    // Node that fills entire background
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    commands
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        .spawn(Node {
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            width: Val::Percent(100.),
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            ..default()
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        })
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        // Text where we display current resolution
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        .with_child((
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            Text::new("Resolution"),
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            TextFont {
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                font_size: 42.0,
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                ..default()
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            },
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            ResolutionText,
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        ));
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}
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/// This system shows how to request the window to a new resolution
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fn toggle_resolution(
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    keys: Res<ButtonInput<KeyCode>>,
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    mut window: Single<&mut Window>,
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    resolution: Res<ResolutionSettings>,
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) {
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    if keys.just_pressed(KeyCode::Digit1) {
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        let res = resolution.small;
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        window.resolution.set(res.x, res.y);
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    }
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    if keys.just_pressed(KeyCode::Digit2) {
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        let res = resolution.medium;
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        window.resolution.set(res.x, res.y);
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    }
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    if keys.just_pressed(KeyCode::Digit3) {
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        let res = resolution.large;
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        window.resolution.set(res.x, res.y);
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    }
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}
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/// This system shows how to respond to a window being resized.
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/// Whenever the window is resized, the text will update with the new resolution.
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fn on_resize_system(
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    mut text: Single<&mut Text, With<ResolutionText>>,
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    mut resize_reader: EventReader<WindowResized>,
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) {
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    for e in resize_reader.read() {
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        // When resolution is being changed
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        text.0 = format!("{:.1} x {:.1}", e.width, e.height);
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    }
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}
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