015f2c69ca
# Objective Continue improving the user experience of our UI Node API in the direction specified by [Bevy's Next Generation Scene / UI System](https://github.com/bevyengine/bevy/discussions/14437) ## Solution As specified in the document above, merge `Style` fields into `Node`, and move "computed Node fields" into `ComputedNode` (I chose this name over something like `ComputedNodeLayout` because it currently contains more than just layout info. If we want to break this up / rename these concepts, lets do that in a separate PR). `Style` has been removed. This accomplishes a number of goals: ## Ergonomics wins Specifying both `Node` and `Style` is now no longer required for non-default styles Before: ```rust commands.spawn(( Node::default(), Style { width: Val::Px(100.), ..default() }, )); ``` After: ```rust commands.spawn(Node { width: Val::Px(100.), ..default() }); ``` ## Conceptual clarity `Style` was never a comprehensive "style sheet". It only defined "core" style properties that all `Nodes` shared. Any "styled property" that couldn't fit that mold had to be in a separate component. A "real" style system would style properties _across_ components (`Node`, `Button`, etc). We have plans to build a true style system (see the doc linked above). By moving the `Style` fields to `Node`, we fully embrace `Node` as the driving concept and remove the "style system" confusion. ## Next Steps * Consider identifying and splitting out "style properties that aren't core to Node". This should not happen for Bevy 0.15. --- ## Migration Guide Move any fields set on `Style` into `Node` and replace all `Style` component usage with `Node`. Before: ```rust commands.spawn(( Node::default(), Style { width: Val::Px(100.), ..default() }, )); ``` After: ```rust commands.spawn(Node { width: Val::Px(100.), ..default() }); ``` For any usage of the "computed node properties" that used to live on `Node`, use `ComputedNode` instead: Before: ```rust fn system(nodes: Query<&Node>) { for node in &nodes { let computed_size = node.size(); } } ``` After: ```rust fn system(computed_nodes: Query<&ComputedNode>) { for computed_node in &computed_nodes { let computed_size = computed_node.size(); } } ```
94 lines
3.1 KiB
Rust
94 lines
3.1 KiB
Rust
//! This example illustrates how to create a button that changes color and text based on its
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//! interaction state.
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use bevy::{color::palettes::basic::*, prelude::*, winit::WinitSettings};
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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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.add_systems(Update, button_system)
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.run();
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}
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const NORMAL_BUTTON: Color = Color::srgb(0.15, 0.15, 0.15);
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const HOVERED_BUTTON: Color = Color::srgb(0.25, 0.25, 0.25);
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const PRESSED_BUTTON: Color = Color::srgb(0.35, 0.75, 0.35);
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fn button_system(
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mut interaction_query: Query<
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(
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&Interaction,
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&mut BackgroundColor,
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&mut BorderColor,
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&Children,
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),
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(Changed<Interaction>, With<Button>),
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>,
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mut text_query: Query<&mut Text>,
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) {
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for (interaction, mut color, mut border_color, children) in &mut interaction_query {
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let mut text = text_query.get_mut(children[0]).unwrap();
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match *interaction {
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Interaction::Pressed => {
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**text = "Press".to_string();
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*color = PRESSED_BUTTON.into();
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border_color.0 = RED.into();
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}
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Interaction::Hovered => {
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**text = "Hover".to_string();
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*color = HOVERED_BUTTON.into();
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border_color.0 = Color::WHITE;
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}
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Interaction::None => {
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**text = "Button".to_string();
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*color = NORMAL_BUTTON.into();
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border_color.0 = Color::BLACK;
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}
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}
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}
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}
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fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
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// ui camera
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commands.spawn(Camera2d);
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commands
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.spawn(Node {
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width: Val::Percent(100.0),
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height: Val::Percent(100.0),
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align_items: AlignItems::Center,
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justify_content: JustifyContent::Center,
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..default()
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})
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.with_children(|parent| {
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parent
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.spawn((
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Button,
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Node {
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width: Val::Px(150.0),
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height: Val::Px(65.0),
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border: UiRect::all(Val::Px(5.0)),
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// horizontally center child text
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justify_content: JustifyContent::Center,
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// vertically center child text
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align_items: AlignItems::Center,
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..default()
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},
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BorderColor(Color::BLACK),
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BorderRadius::MAX,
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BackgroundColor(NORMAL_BUTTON),
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))
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.with_child((
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Text::new("Button"),
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TextFont {
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font: asset_server.load("fonts/FiraSans-Bold.ttf"),
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font_size: 33.0,
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..default()
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},
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TextColor(Color::srgb(0.9, 0.9, 0.9)),
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));
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});
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}
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