bevy/examples/ui/borders.rs
Chris Biscardi 56405890f2
refactor ui/borders example to use new children! macro (#18962)
# Objective

Refactor
[`examples/ui/borders.rs`](7f0490655c/examples/ui/borders.rs)
to use the new spawning/hierarchy APIs in 0.16.

## Solution

This refactor reduces the number of `.spawn` calls from about 16 to 2,
using one spawn for each major feature:

* camera2d
* ui layout

The `Children::spawn` relationship API is used to take advantage of
`SpawnIter` for the borders examples in each block.

Each block of examples now returns a Bundle into its respective
variable, which is then used in combination with the new `label` widget
which makes use of the new `impl Bundle` return capability. This allows
the ui layout to use a single `.spawn` with the `children!` macro.

The blocks of examples are still in separate variables because it felt
like a useful way to organize it still, even without needing to spawn at
those locations.

Functionality of the demo hasn't changed, this is just an API/code
update.

## Showcase

![screenshot-2025-04-27-at-18 05
19@2x](https://github.com/user-attachments/assets/5f10b28b-b0f1-4a55-af9f-2e7b05b7b4bf)

<details>
<summary>Before screenshot</summary>

![screenshot-2025-04-27-at-18 17
12@2x](https://github.com/user-attachments/assets/ae159d96-ba4d-4429-b934-7779470c480a)

</details>

---------

Co-authored-by: François Mockers <mockersf@gmail.com>
2025-05-04 08:35:03 +00:00

247 lines
7.9 KiB
Rust

//! Example demonstrating bordered UI nodes
use bevy::{color::palettes::css::*, ecs::spawn::SpawnIter, prelude::*};
fn main() {
App::new()
.add_plugins(DefaultPlugins)
.add_systems(Startup, setup)
.run();
}
fn setup(mut commands: Commands) {
commands.spawn(Camera2d);
// labels for the different border edges
let border_labels = [
"None",
"All",
"Left",
"Right",
"Top",
"Bottom",
"Horizontal",
"Vertical",
"Top Left",
"Bottom Left",
"Top Right",
"Bottom Right",
"Top Bottom Right",
"Top Bottom Left",
"Top Left Right",
"Bottom Left Right",
];
// all the different combinations of border edges
// these correspond to the labels above
let borders = [
UiRect::default(),
UiRect::all(Val::Px(10.)),
UiRect::left(Val::Px(10.)),
UiRect::right(Val::Px(10.)),
UiRect::top(Val::Px(10.)),
UiRect::bottom(Val::Px(10.)),
UiRect::horizontal(Val::Px(10.)),
UiRect::vertical(Val::Px(10.)),
UiRect {
left: Val::Px(20.),
top: Val::Px(10.),
..default()
},
UiRect {
left: Val::Px(10.),
bottom: Val::Px(20.),
..default()
},
UiRect {
right: Val::Px(20.),
top: Val::Px(10.),
..default()
},
UiRect {
right: Val::Px(10.),
bottom: Val::Px(10.),
..default()
},
UiRect {
right: Val::Px(10.),
top: Val::Px(20.),
bottom: Val::Px(10.),
..default()
},
UiRect {
left: Val::Px(10.),
top: Val::Px(10.),
bottom: Val::Px(10.),
..default()
},
UiRect {
left: Val::Px(20.),
right: Val::Px(10.),
top: Val::Px(10.),
..default()
},
UiRect {
left: Val::Px(10.),
right: Val::Px(10.),
bottom: Val::Px(20.),
..default()
},
];
let borders_examples = (
Node {
margin: UiRect::all(Val::Px(25.0)),
align_self: AlignSelf::Stretch,
justify_self: JustifySelf::Stretch,
flex_wrap: FlexWrap::Wrap,
justify_content: JustifyContent::FlexStart,
align_items: AlignItems::FlexStart,
align_content: AlignContent::FlexStart,
..default()
},
Children::spawn(SpawnIter(border_labels.into_iter().zip(borders).map(
|(label, border)| {
(
Node {
flex_direction: FlexDirection::Column,
align_items: AlignItems::Center,
..default()
},
children![
(
Node {
width: Val::Px(50.),
height: Val::Px(50.),
border,
margin: UiRect::all(Val::Px(20.)),
align_items: AlignItems::Center,
justify_content: JustifyContent::Center,
..default()
},
BackgroundColor(MAROON.into()),
BorderColor(RED.into()),
Outline {
width: Val::Px(6.),
offset: Val::Px(6.),
color: Color::WHITE,
},
children![(
Node {
width: Val::Px(10.),
height: Val::Px(10.),
..default()
},
BackgroundColor(YELLOW.into()),
)]
),
(Text::new(label), TextFont::from_font_size(9.0))
],
)
},
))),
);
let non_zero = |x, y| x != Val::Px(0.) && y != Val::Px(0.);
let border_size = move |x, y| {
if non_zero(x, y) {
f32::MAX
} else {
0.
}
};
let borders_examples_rounded = (
Node {
margin: UiRect::all(Val::Px(25.0)),
align_self: AlignSelf::Stretch,
justify_self: JustifySelf::Stretch,
flex_wrap: FlexWrap::Wrap,
justify_content: JustifyContent::FlexStart,
align_items: AlignItems::FlexStart,
align_content: AlignContent::FlexStart,
..default()
},
Children::spawn(SpawnIter(border_labels.into_iter().zip(borders).map(
move |(label, border)| {
(
Node {
flex_direction: FlexDirection::Column,
align_items: AlignItems::Center,
..default()
},
children![
(
Node {
width: Val::Px(50.),
height: Val::Px(50.),
border,
margin: UiRect::all(Val::Px(20.)),
align_items: AlignItems::Center,
justify_content: JustifyContent::Center,
..default()
},
BackgroundColor(MAROON.into()),
BorderColor(RED.into()),
BorderRadius::px(
border_size(border.left, border.top),
border_size(border.right, border.top),
border_size(border.right, border.bottom,),
border_size(border.left, border.bottom),
),
Outline {
width: Val::Px(6.),
offset: Val::Px(6.),
color: Color::WHITE,
},
children![(
Node {
width: Val::Px(10.),
height: Val::Px(10.),
..default()
},
BorderRadius::MAX,
BackgroundColor(YELLOW.into()),
)],
),
(Text::new(label), TextFont::from_font_size(9.0))
],
)
},
))),
);
commands.spawn((
Node {
margin: UiRect::all(Val::Px(25.0)),
flex_direction: FlexDirection::Column,
align_self: AlignSelf::Stretch,
justify_self: JustifySelf::Stretch,
flex_wrap: FlexWrap::Wrap,
justify_content: JustifyContent::FlexStart,
align_items: AlignItems::FlexStart,
align_content: AlignContent::FlexStart,
..default()
},
BackgroundColor(Color::srgb(0.25, 0.25, 0.25)),
children![
label("Borders"),
borders_examples,
label("Borders Rounded"),
borders_examples_rounded
],
));
}
// A label widget that accepts a &str and returns
// a Bundle that can be spawned
fn label(text: &str) -> impl Bundle {
(
Node {
margin: UiRect::all(Val::Px(25.0)),
..default()
},
children![(Text::new(text), TextFont::from_font_size(20.0))],
)
}