**Ready for review. Examples migration progress: 100%.** # Objective - Implement https://github.com/bevyengine/bevy/discussions/15014 ## Solution This implements [cart's proposal](https://github.com/bevyengine/bevy/discussions/15014#discussioncomment-10574459) faithfully except for one change. I separated `TextSpan` from `TextSpan2d` because `TextSpan` needs to require the `GhostNode` component, which is a `bevy_ui` component only usable by UI. Extra changes: - Added `EntityCommands::commands_mut` that returns a mutable reference. This is a blocker for extension methods that return something other than `self`. Note that `sickle_ui`'s `UiBuilder::commands` returns a mutable reference for this reason. ## Testing - [x] Text examples all work. --- ## Showcase TODO: showcase-worthy ## Migration Guide TODO: very breaking ### Accessing text spans by index Text sections are now text sections on different entities in a hierarchy, Use the new `TextReader` and `TextWriter` system parameters to access spans by index. Before: ```rust fn refresh_text(mut query: Query<&mut Text, With<TimeText>>, time: Res<Time>) { let text = query.single_mut(); text.sections[1].value = format_time(time.elapsed()); } ``` After: ```rust fn refresh_text( query: Query<Entity, With<TimeText>>, mut writer: UiTextWriter, time: Res<Time> ) { let entity = query.single(); *writer.text(entity, 1) = format_time(time.elapsed()); } ``` ### Iterating text spans Text spans are now entities in a hierarchy, so the new `UiTextReader` and `UiTextWriter` system parameters provide ways to iterate that hierarchy. The `UiTextReader::iter` method will give you a normal iterator over spans, and `UiTextWriter::for_each` lets you visit each of the spans. --------- Co-authored-by: ickshonpe <david.curthoys@googlemail.com> Co-authored-by: Carter Anderson <mcanders1@gmail.com>
		
			
				
	
	
		
			93 lines
		
	
	
		
			3.0 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
			
		
		
	
	
			93 lines
		
	
	
		
			3.0 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
//! Showcases the [`RelativeCursorPosition`] component, used to check the position of the cursor relative to a UI node.
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use bevy::{
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    prelude::*, render::camera::Viewport, ui::RelativeCursorPosition, winit::WinitSettings,
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};
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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, relative_cursor_position_system)
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        .run();
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}
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fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
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    commands.spawn((
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        Camera2d,
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        Camera {
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            // Cursor position will take the viewport offset into account
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            viewport: Some(Viewport {
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                physical_position: [200, 100].into(),
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                physical_size: [600, 600].into(),
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                ..default()
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            }),
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            ..default()
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        },
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    ));
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    commands
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        .spawn(NodeBundle {
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            style: Style {
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                width: Val::Percent(100.),
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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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                flex_direction: FlexDirection::Column,
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                ..default()
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            },
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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(NodeBundle {
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                    style: Style {
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                        width: Val::Px(250.),
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                        height: Val::Px(250.),
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                        margin: UiRect::bottom(Val::Px(15.)),
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                        ..default()
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                    },
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                    background_color: Color::srgb(235., 35., 12.).into(),
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                    ..default()
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                })
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                .insert(RelativeCursorPosition::default());
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            parent.spawn((
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                Text::new("(0.0, 0.0)"),
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                TextStyle {
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                    font: asset_server.load("fonts/FiraSans-Bold.ttf"),
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                    font_size: 33.0,
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                    color: Color::srgb(0.9, 0.9, 0.9),
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                    ..default()
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                },
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            ));
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        });
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}
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/// This systems polls the relative cursor position and displays its value in a text component.
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fn relative_cursor_position_system(
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    relative_cursor_position_query: Query<&RelativeCursorPosition>,
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    mut output_query: Query<(&mut Text, &mut TextStyle)>,
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) {
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    let relative_cursor_position = relative_cursor_position_query.single();
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    let (mut output, mut style) = output_query.single_mut();
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    **output = if let Some(relative_cursor_position) = relative_cursor_position.normalized {
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        format!(
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            "({:.1}, {:.1})",
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            relative_cursor_position.x, relative_cursor_position.y
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        )
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    } else {
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        "unknown".to_string()
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    };
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    style.color = if relative_cursor_position.mouse_over() {
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        Color::srgb(0.1, 0.9, 0.1)
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    } else {
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        Color::srgb(0.9, 0.1, 0.1)
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    };
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}
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