mirror of
https://github.com/bevyengine/bevy
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99b9a2fcd7
# Objective
UI box shadow support
Adds a new component `BoxShadow`:
```rust
pub struct BoxShadow {
/// The shadow's color
pub color: Color,
/// Horizontal offset
pub x_offset: Val,
/// Vertical offset
pub y_offset: Val,
/// Horizontal difference in size from the occluding uninode
pub spread_radius: Val,
/// Blurriness of the shadow
pub blur_radius: Val,
}
```
To use `BoxShadow`, add the component to any Bevy UI node and a shadow
will be drawn beneath that node.
Also adds a resource `BoxShadowSamples` that can be used to adjust the
shadow quality.
#### Notes
* I'm not super happy with the field names. Maybe we need a `struct Size
{ width: Val, height: Val }` type or something.
* The shader isn't very optimised but I don't see that it's too
important for now as the number of shadows being rendered is not going
to be massive most of the time. I think it's more important to get the
API and geometry correct with this PR.
* I didn't implement an inset property, it's not essential and can
easily be added in a follow up.
* Shadows are only rendered for uinodes, not for images or text.
* Batching isn't supported, it would need out-of-the-scope-of-this-pr
changes to the way the UI handles z-ordering for it to be effective.
# Showcase
```cargo run --example box_shadow -- --samples 4```
<img width="391" alt="br" src="https://github.com/user-attachments/assets/4e8add96-dc93-46e0-9e35-d995eb0943ad">
```cargo run --example box_shadow -- --samples 10```
<img width="391" alt="s10"
src="https://github.com/user-attachments/assets/ecb384c9-4012-4cd6-9dea-5180904bf28e">
224 lines
6.7 KiB
Rust
224 lines
6.7 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(NodeBundle {
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style: Style {
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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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background_color: BackgroundColor(DEEP_SKY_BLUE.into()),
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..Default::default()
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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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NodeBundle {
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style: Style {
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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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border_color: BorderColor(LIGHT_SKY_BLUE.into()),
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border_radius,
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background_color: BackgroundColor(DEEP_SKY_BLUE.into()),
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..Default::default()
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},
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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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