This example is running in WebGL2 and should work in most browsers. You can check the WebGPU examples here.
button.rs:
//! This example illustrates how to create a button that changes color and text based on its
//! interaction state.
use bevy::{color::palettes::basic::*, 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_systems(Startup, setup)
.add_systems(Update, button_system)
.run();
}
const NORMAL_BUTTON: Color = Color::srgb(0.15, 0.15, 0.15);
const HOVERED_BUTTON: Color = Color::srgb(0.25, 0.25, 0.25);
const PRESSED_BUTTON: Color = Color::srgb(0.35, 0.75, 0.35);
fn button_system(
mut interaction_query: Query<
(
&Interaction,
&mut BackgroundColor,
&mut BorderColor,
&Children,
),
(Changed<Interaction>, With<Button>),
>,
mut text_query: Query<&mut Text>,
) {
for (interaction, mut color, mut border_color, children) in &mut interaction_query {
let mut text = text_query.get_mut(children[0]).unwrap();
match *interaction {
Interaction::Pressed => {
text.sections[0].value = "Press".to_string();
*color = PRESSED_BUTTON.into();
border_color.0 = RED.into();
}
Interaction::Hovered => {
text.sections[0].value = "Hover".to_string();
*color = HOVERED_BUTTON.into();
border_color.0 = Color::WHITE;
}
Interaction::None => {
text.sections[0].value = "Button".to_string();
*color = NORMAL_BUTTON.into();
border_color.0 = Color::BLACK;
}
}
}
}
fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
// ui camera
commands.spawn(Camera2dBundle::default());
commands
.spawn(NodeBundle {
style: Style {
width: Val::Percent(100.0),
height: Val::Percent(100.0),
align_items: AlignItems::Center,
justify_content: JustifyContent::Center,
..default()
},
..default()
})
.with_children(|parent| {
parent
.spawn(ButtonBundle {
style: Style {
width: Val::Px(150.0),
height: Val::Px(65.0),
border: UiRect::all(Val::Px(5.0)),
// horizontally center child text
justify_content: JustifyContent::Center,
// vertically center child text
align_items: AlignItems::Center,
..default()
},
border_color: BorderColor(Color::BLACK),
border_radius: BorderRadius::MAX,
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::srgb(0.9, 0.9, 0.9),
},
));
});
});
}