bevy/examples/ui/button.rs
ickshonpe eaac730617 Fix the Size helper functions using the wrong default value and improve the UI examples (#7626)
# Objective
`Size::width` sets the `height` field to `Val::DEFAULT` which is `Val::Undefined`, but the default for `Size` `height` is `Val::Auto`. 
`Size::height` has the same problem, but with the `width` field. 

The UI examples specify numeric values in many places where they could either be elided or replaced by composition of the Flex enum properties.

related: https://github.com/bevyengine/bevy/pull/7468
fixes: https://github.com/bevyengine/bevy/issues/6498

## Solution
Change `Size::width` so it sets `height` to `Val::AUTO` and change `Size::height` so it sets `width` to `Val::AUTO`.
Added some tests so this doesn't happen again.

## Changelog
Changed `Size::width` so it sets the `height` to `Val::AUTO`.
Changed `Size::height` so it sets the `width` to `Val::AUTO`.
Added tests to `geometry.rs` for `Size` and `UiRect` to ensure correct behaviour.
Simplified the UI examples. Replaced numeric values with the Flex property enums or elided them where possible, and removed the remaining use of auto margins.

## Migration Guide
The `Size::width` constructor function now sets the `height` to `Val::Auto` instead of `Val::Undefined`.
The `Size::height` constructor function now sets the `width` to `Val::Auto` instead of `Val::Undefined`.
2023-02-11 23:07:16 +00:00

84 lines
2.9 KiB
Rust

//! This example illustrates how to create a button that changes color and text based on its
//! interaction state.
use bevy::{prelude::*, winit::WinitSettings};
fn main() {
App::new()
.add_plugins(DefaultPlugins)
// Only run the app when there is user input. This will significantly reduce CPU/GPU use.
.insert_resource(WinitSettings::desktop_app())
.add_startup_system(setup)
.add_system(button_system)
.run();
}
const NORMAL_BUTTON: Color = Color::rgb(0.15, 0.15, 0.15);
const HOVERED_BUTTON: Color = Color::rgb(0.25, 0.25, 0.25);
const PRESSED_BUTTON: Color = Color::rgb(0.35, 0.75, 0.35);
fn button_system(
mut interaction_query: Query<
(&Interaction, &mut BackgroundColor, &Children),
(Changed<Interaction>, With<Button>),
>,
mut text_query: Query<&mut Text>,
) {
for (interaction, mut color, children) in &mut interaction_query {
let mut text = text_query.get_mut(children[0]).unwrap();
match *interaction {
Interaction::Clicked => {
text.sections[0].value = "Press".to_string();
*color = PRESSED_BUTTON.into();
}
Interaction::Hovered => {
text.sections[0].value = "Hover".to_string();
*color = HOVERED_BUTTON.into();
}
Interaction::None => {
text.sections[0].value = "Button".to_string();
*color = NORMAL_BUTTON.into();
}
}
}
}
fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
// ui camera
commands.spawn(Camera2dBundle::default());
commands
.spawn(NodeBundle {
style: Style {
size: Size::width(Val::Percent(100.0)),
align_items: AlignItems::Center,
justify_content: JustifyContent::Center,
..default()
},
..default()
})
.with_children(|parent| {
parent
.spawn(ButtonBundle {
style: Style {
size: Size::new(Val::Px(150.0), Val::Px(65.0)),
// horizontally center child text
justify_content: JustifyContent::Center,
// vertically center child text
align_items: AlignItems::Center,
..default()
},
background_color: NORMAL_BUTTON.into(),
..default()
})
.with_children(|parent| {
parent.spawn(TextBundle::from_section(
"Button",
TextStyle {
font: asset_server.load("fonts/FiraSans-Bold.ttf"),
font_size: 40.0,
color: Color::rgb(0.9, 0.9, 0.9),
},
));
});
});
}