# 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(); } } ```
		
			
				
	
	
		
			106 lines
		
	
	
		
			3.1 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
			
		
		
	
	
			106 lines
		
	
	
		
			3.1 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
//! Displays information about available monitors (displays).
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use bevy::{
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    prelude::*,
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    render::camera::RenderTarget,
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    window::{ExitCondition, Monitor, WindowMode, WindowRef},
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};
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fn main() {
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    App::new()
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        .add_plugins(DefaultPlugins.set(WindowPlugin {
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            primary_window: None,
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            exit_condition: ExitCondition::DontExit,
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            ..default()
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        }))
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        .add_systems(Update, (update, close_on_esc))
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        .run();
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}
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#[derive(Component)]
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struct MonitorRef(Entity);
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fn update(
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    mut commands: Commands,
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    monitors_added: Query<(Entity, &Monitor), Added<Monitor>>,
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    mut monitors_removed: RemovedComponents<Monitor>,
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    monitor_refs: Query<(Entity, &MonitorRef)>,
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) {
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    for (entity, monitor) in monitors_added.iter() {
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        // Spawn a new window on each monitor
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        let name = monitor.name.clone().unwrap_or_else(|| "<no name>".into());
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        let size = format!("{}x{}px", monitor.physical_height, monitor.physical_width);
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        let hz = monitor
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            .refresh_rate_millihertz
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            .map(|x| format!("{}Hz", x as f32 / 1000.0))
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            .unwrap_or_else(|| "<unknown>".into());
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        let position = format!(
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            "x={} y={}",
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            monitor.physical_position.x, monitor.physical_position.y
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        );
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        let scale = format!("{:.2}", monitor.scale_factor);
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        let window = commands
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            .spawn((
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                Window {
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                    title: name.clone(),
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                    mode: WindowMode::Fullscreen(MonitorSelection::Entity(entity)),
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                    position: WindowPosition::Centered(MonitorSelection::Entity(entity)),
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                    ..default()
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                },
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                MonitorRef(entity),
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            ))
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            .id();
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        let camera = commands
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            .spawn((
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                Camera2d,
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                Camera {
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                    target: RenderTarget::Window(WindowRef::Entity(window)),
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                    ..default()
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                },
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            ))
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            .id();
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        let info_text = format!(
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            "Monitor: {name}\nSize: {size}\nRefresh rate: {hz}\nPosition: {position}\nScale: {scale}\n\n",
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        );
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        commands.spawn((
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            Text(info_text),
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            Node {
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                position_type: PositionType::Relative,
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                height: Val::Percent(100.0),
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                width: Val::Percent(100.0),
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                ..default()
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            },
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            TargetCamera(camera),
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            MonitorRef(entity),
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        ));
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    }
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    // Remove windows for removed monitors
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    for monitor_entity in monitors_removed.read() {
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        for (ref_entity, monitor_ref) in monitor_refs.iter() {
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            if monitor_ref.0 == monitor_entity {
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                commands.entity(ref_entity).despawn_recursive();
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            }
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        }
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    }
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}
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fn close_on_esc(
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    mut commands: Commands,
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    focused_windows: Query<(Entity, &Window)>,
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    input: Res<ButtonInput<KeyCode>>,
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) {
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    for (window, focus) in focused_windows.iter() {
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        if !focus.focused {
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            continue;
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        }
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        if input.just_pressed(KeyCode::Escape) {
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            commands.entity(window).despawn();
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        }
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    }
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}
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