bevy/examples/ui/relative_cursor_position.rs
ickshonpe 373f1eeb1e
UI examples clean up (#9479)
# Objective

Fix a few issues with some of the examples:

* Root UI nodes have an implicit parent with `FlexDirection::Row` and
`AlignItems::Stretch` set. Only a width constraint is needed to fill the
viewport. Specifying ```height: Val::Percent(100.)``` is unnecessary and
can cause confusing overflow behaviour.

* The default for position and size constraint properties is
`Val::Auto`. Setting `left: Val::Auto`, `max_height: Val::Auto`, etc
does nothing.


## Solution

Delete those lines. There should be no observable differences in the
behaviours of any of the examples.

Also changed a padding setting in the `flex_layout` example to use the
`axes` helper function.
2023-08-23 12:49:10 +00:00

81 lines
2.7 KiB
Rust

//! Showcases the [`RelativeCursorPosition`] component, used to check the position of the cursor relative to a UI node.
use bevy::{prelude::*, ui::RelativeCursorPosition, 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, relative_cursor_position_system)
.run();
}
fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
commands.spawn(Camera2dBundle::default());
commands
.spawn(NodeBundle {
style: Style {
width: Val::Percent(100.),
align_items: AlignItems::Center,
justify_content: JustifyContent::Center,
flex_direction: FlexDirection::Column,
..default()
},
..default()
})
.with_children(|parent| {
parent
.spawn(NodeBundle {
style: Style {
width: Val::Px(250.),
height: Val::Px(250.),
margin: UiRect::bottom(Val::Px(15.)),
..default()
},
background_color: Color::rgb(235., 35., 12.).into(),
..default()
})
.insert(RelativeCursorPosition::default());
parent.spawn(TextBundle {
text: Text::from_section(
"(0.0, 0.0)",
TextStyle {
font: asset_server.load("fonts/FiraSans-Bold.ttf"),
font_size: 40.0,
color: Color::rgb(0.9, 0.9, 0.9),
},
),
..default()
});
});
}
/// This systems polls the relative cursor position and displays its value in a text component.
fn relative_cursor_position_system(
relative_cursor_position_query: Query<&RelativeCursorPosition>,
mut output_query: Query<&mut Text>,
) {
let relative_cursor_position = relative_cursor_position_query.single();
let mut output = output_query.single_mut();
output.sections[0].value =
if let Some(relative_cursor_position) = relative_cursor_position.normalized {
format!(
"({:.1}, {:.1})",
relative_cursor_position.x, relative_cursor_position.y
)
} else {
"unknown".to_string()
};
output.sections[0].style.color = if relative_cursor_position.mouse_over() {
Color::rgb(0.1, 0.9, 0.1)
} else {
Color::rgb(0.9, 0.1, 0.1)
};
}