# 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(); } } ```
		
			
				
	
	
		
			221 lines
		
	
	
		
			6.5 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
			
		
		
	
	
			221 lines
		
	
	
		
			6.5 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
//! This example shows how to create a node with a shadow
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use argh::FromArgs;
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use bevy::color::palettes::css::DEEP_SKY_BLUE;
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use bevy::color::palettes::css::LIGHT_SKY_BLUE;
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use bevy::prelude::*;
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use bevy::winit::WinitSettings;
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#[derive(FromArgs, Resource)]
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/// `box_shadow` example
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struct Args {
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    /// number of samples
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    #[argh(option, default = "4")]
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    samples: u32,
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}
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fn main() {
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    App::new()
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        .add_plugins(DefaultPlugins)
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        // Only run the app when there is user input. This will significantly reduce CPU/GPU use.
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        .insert_resource(WinitSettings::desktop_app())
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        .add_systems(Startup, setup)
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        .run();
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}
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fn setup(mut commands: Commands) {
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    // `from_env` panics on the web
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    #[cfg(not(target_arch = "wasm32"))]
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    let args: Args = argh::from_env();
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    #[cfg(target_arch = "wasm32")]
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    let args = Args::from_args(&[], &[]).unwrap();
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    // ui camera
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    commands.spawn((Camera2d, UiBoxShadowSamples(args.samples)));
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    commands
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        .spawn((
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            Node {
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                width: Val::Percent(100.0),
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                height: Val::Percent(100.0),
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                padding: UiRect::all(Val::Px(30.)),
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                column_gap: Val::Px(30.),
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                flex_wrap: FlexWrap::Wrap,
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                ..default()
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            },
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            BackgroundColor(DEEP_SKY_BLUE.into()),
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        ))
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        .with_children(|commands| {
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            let example_nodes = [
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                (
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                    Vec2::splat(50.),
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                    Vec2::ZERO,
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                    10.,
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                    0.,
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                    BorderRadius::bottom_right(Val::Px(10.)),
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                ),
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                (Vec2::new(50., 25.), Vec2::ZERO, 10., 0., BorderRadius::ZERO),
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                (Vec2::splat(50.), Vec2::ZERO, 10., 0., BorderRadius::MAX),
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                (Vec2::new(100., 25.), Vec2::ZERO, 10., 0., BorderRadius::MAX),
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                (
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                    Vec2::splat(50.),
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                    Vec2::ZERO,
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                    10.,
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                    0.,
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                    BorderRadius::bottom_right(Val::Px(10.)),
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                ),
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                (Vec2::new(50., 25.), Vec2::ZERO, 0., 10., BorderRadius::ZERO),
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                (
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                    Vec2::splat(50.),
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                    Vec2::ZERO,
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                    0.,
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                    10.,
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                    BorderRadius::bottom_right(Val::Px(10.)),
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                ),
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                (Vec2::new(100., 25.), Vec2::ZERO, 0., 10., BorderRadius::MAX),
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                (
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                    Vec2::splat(50.),
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                    Vec2::splat(25.),
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                    0.,
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                    0.,
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                    BorderRadius::ZERO,
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                ),
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                (
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                    Vec2::new(50., 25.),
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                    Vec2::splat(25.),
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                    0.,
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                    0.,
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                    BorderRadius::ZERO,
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                ),
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                (
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                    Vec2::splat(50.),
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                    Vec2::splat(10.),
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                    0.,
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                    0.,
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                    BorderRadius::bottom_right(Val::Px(10.)),
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                ),
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                (
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                    Vec2::splat(50.),
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                    Vec2::splat(25.),
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                    0.,
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                    10.,
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                    BorderRadius::ZERO,
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                ),
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                (
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                    Vec2::new(50., 25.),
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                    Vec2::splat(25.),
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                    0.,
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                    10.,
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                    BorderRadius::ZERO,
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                ),
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                (
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                    Vec2::splat(50.),
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                    Vec2::splat(10.),
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                    0.,
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                    10.,
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                    BorderRadius::bottom_right(Val::Px(10.)),
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                ),
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                (
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                    Vec2::splat(50.),
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                    Vec2::splat(10.),
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                    0.,
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                    3.,
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                    BorderRadius::ZERO,
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                ),
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                (
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                    Vec2::new(50., 25.),
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                    Vec2::splat(10.),
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                    0.,
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                    3.,
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                    BorderRadius::ZERO,
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                ),
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                (
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                    Vec2::splat(50.),
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                    Vec2::splat(10.),
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                    0.,
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                    3.,
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                    BorderRadius::bottom_right(Val::Px(10.)),
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                ),
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                (
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                    Vec2::splat(50.),
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                    Vec2::splat(10.),
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                    0.,
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                    3.,
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                    BorderRadius::all(Val::Px(20.)),
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                ),
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                (
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                    Vec2::new(50., 25.),
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                    Vec2::splat(10.),
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                    0.,
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                    3.,
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                    BorderRadius::all(Val::Px(20.)),
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                ),
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                (
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                    Vec2::new(25., 50.),
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                    Vec2::splat(10.),
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                    0.,
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                    3.,
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                    BorderRadius::MAX,
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                ),
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                (
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                    Vec2::splat(50.),
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                    Vec2::splat(10.),
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                    0.,
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                    10.,
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                    BorderRadius::all(Val::Px(20.)),
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                ),
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                (
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                    Vec2::new(50., 25.),
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                    Vec2::splat(10.),
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                    0.,
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                    10.,
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                    BorderRadius::all(Val::Px(20.)),
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                ),
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                (
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                    Vec2::new(25., 50.),
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                    Vec2::splat(10.),
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                    0.,
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                    10.,
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                    BorderRadius::MAX,
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                ),
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            ];
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            for (size, offset, spread, blur, border_radius) in example_nodes {
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                commands.spawn(box_shadow_node_bundle(
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                    size,
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                    offset,
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                    spread,
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                    blur,
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                    border_radius,
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                ));
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            }
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        });
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}
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fn box_shadow_node_bundle(
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    size: Vec2,
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    offset: Vec2,
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    spread: f32,
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    blur: f32,
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    border_radius: BorderRadius,
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) -> impl Bundle {
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    (
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        Node {
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            width: Val::Px(size.x),
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            height: Val::Px(size.y),
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            border: UiRect::all(Val::Px(4.)),
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            ..default()
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        },
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        BorderColor(LIGHT_SKY_BLUE.into()),
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        border_radius,
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        BackgroundColor(DEEP_SKY_BLUE.into()),
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        BoxShadow {
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            color: Color::BLACK.with_alpha(0.8),
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            x_offset: Val::Percent(offset.x),
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            y_offset: Val::Percent(offset.y),
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            spread_radius: Val::Percent(spread),
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            blur_radius: Val::Px(blur),
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        },
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    )
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}
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