# Objective - Improve clarity when spawning a text block. See [this discussion](https://github.com/bevyengine/bevy/pull/15591/#discussion_r1787083571). ## Solution - Rename `TextBlock` to `TextLayout`.
		
			
				
	
	
		
			390 lines
		
	
	
		
			14 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
			
		
		
	
	
			390 lines
		
	
	
		
			14 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
//! Demonstrates how the to use the size constraints to control the size of a UI node.
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use bevy::{color::palettes::css::*, prelude::*};
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fn main() {
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    App::new()
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        .add_plugins(DefaultPlugins)
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        .add_event::<ButtonActivatedEvent>()
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        .add_systems(Startup, setup)
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        .add_systems(Update, (update_buttons, update_radio_buttons_colors))
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        .run();
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}
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const ACTIVE_BORDER_COLOR: Color = Color::Srgba(ANTIQUE_WHITE);
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const INACTIVE_BORDER_COLOR: Color = Color::BLACK;
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const ACTIVE_INNER_COLOR: Color = Color::WHITE;
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const INACTIVE_INNER_COLOR: Color = Color::Srgba(NAVY);
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const ACTIVE_TEXT_COLOR: Color = Color::BLACK;
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const HOVERED_TEXT_COLOR: Color = Color::WHITE;
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const UNHOVERED_TEXT_COLOR: Color = Color::srgb(0.5, 0.5, 0.5);
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#[derive(Component)]
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struct Bar;
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#[derive(Copy, Clone, Debug, Component, PartialEq)]
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enum Constraint {
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    FlexBasis,
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    Width,
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    MinWidth,
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    MaxWidth,
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}
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#[derive(Copy, Clone, Component)]
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struct ButtonValue(Val);
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#[derive(Event)]
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struct ButtonActivatedEvent(Entity);
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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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    let text_style = 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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    commands
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        .spawn(NodeBundle {
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            style: Style {
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                width: Val::Percent(100.0),
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                height: Val::Percent(100.0),
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                justify_content: JustifyContent::Center,
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                align_items: AlignItems::Center,
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                ..Default::default()
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            },
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            background_color: Color::BLACK.into(),
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            ..Default::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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                        flex_direction: FlexDirection::Column,
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                        align_items: AlignItems::Center,
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                        justify_content: JustifyContent::Center,
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                        ..Default::default()
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                    },
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                    ..Default::default()
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                })
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                .with_children(|parent| {
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                    parent.spawn((
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                        Text::new("Size Constraints Example"),
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                        text_style.clone(),
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                        Style {
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                            margin: UiRect::bottom(Val::Px(25.)),
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                            ..Default::default()
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                        },
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                    ));
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                    spawn_bar(parent);
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                    parent
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                        .spawn(NodeBundle {
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                            style: Style {
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                                flex_direction: FlexDirection::Column,
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                                align_items: AlignItems::Stretch,
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                                padding: UiRect::all(Val::Px(10.)),
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                                margin: UiRect::top(Val::Px(50.)),
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                                ..Default::default()
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                            },
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                            background_color: YELLOW.into(),
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                            ..Default::default()
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                        })
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                        .with_children(|parent| {
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                            for constraint in [
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                                Constraint::MinWidth,
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                                Constraint::FlexBasis,
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                                Constraint::Width,
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                                Constraint::MaxWidth,
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                            ] {
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                                spawn_button_row(parent, constraint, text_style.clone());
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                            }
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                        });
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                });
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        });
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}
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fn spawn_bar(parent: &mut ChildBuilder) {
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    parent
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        .spawn(NodeBundle {
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            style: Style {
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                flex_basis: Val::Percent(100.0),
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                align_self: AlignSelf::Stretch,
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                padding: UiRect::all(Val::Px(10.)),
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                ..Default::default()
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            },
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            background_color: YELLOW.into(),
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            ..Default::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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                        align_items: AlignItems::Stretch,
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                        width: Val::Percent(100.),
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                        height: Val::Px(100.),
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                        padding: UiRect::all(Val::Px(4.)),
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                        ..Default::default()
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                    },
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                    background_color: Color::BLACK.into(),
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                    ..Default::default()
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                })
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                .with_children(|parent| {
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                    parent.spawn((
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                        NodeBundle {
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                            style: Style {
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                                ..Default::default()
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                            },
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                            background_color: Color::WHITE.into(),
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                            ..Default::default()
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                        },
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                        Bar,
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                    ));
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                });
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        });
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}
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fn spawn_button_row(parent: &mut ChildBuilder, constraint: Constraint, text_style: TextStyle) {
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    let label = match constraint {
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        Constraint::FlexBasis => "flex_basis",
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        Constraint::Width => "size",
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        Constraint::MinWidth => "min_size",
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        Constraint::MaxWidth => "max_size",
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    };
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    parent
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        .spawn(NodeBundle {
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            style: Style {
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                flex_direction: FlexDirection::Column,
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                padding: UiRect::all(Val::Px(2.)),
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                align_items: AlignItems::Stretch,
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                ..Default::default()
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            },
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            background_color: Color::BLACK.into(),
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            ..Default::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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                        flex_direction: FlexDirection::Row,
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                        justify_content: JustifyContent::End,
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                        padding: UiRect::all(Val::Px(2.)),
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                        ..Default::default()
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                    },
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                    ..Default::default()
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                })
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                .with_children(|parent| {
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                    // spawn row label
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                    parent
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                        .spawn(NodeBundle {
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                            style: Style {
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                                min_width: Val::Px(200.),
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                                max_width: Val::Px(200.),
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                                justify_content: JustifyContent::Center,
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                                align_items: AlignItems::Center,
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                                ..Default::default()
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                            },
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                            ..Default::default()
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                        })
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                        .with_child((Text::new(label), text_style.clone()));
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                    // spawn row buttons
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                    parent
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                        .spawn(NodeBundle {
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                            ..Default::default()
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                        })
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                        .with_children(|parent| {
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                            spawn_button(
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                                parent,
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                                constraint,
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                                ButtonValue(Val::Auto),
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                                "Auto".to_string(),
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                                text_style.clone(),
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                                true,
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                            );
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                            for percent in [0., 25., 50., 75., 100., 125.] {
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                                spawn_button(
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                                    parent,
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                                    constraint,
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                                    ButtonValue(Val::Percent(percent)),
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                                    format!("{percent}%"),
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                                    text_style.clone(),
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                                    false,
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                                );
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                            }
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                        });
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                });
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        });
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}
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fn spawn_button(
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    parent: &mut ChildBuilder,
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    constraint: Constraint,
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    action: ButtonValue,
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    label: String,
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    text_style: TextStyle,
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    active: bool,
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) {
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    parent
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        .spawn((
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            ButtonBundle {
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                style: Style {
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                    align_items: AlignItems::Center,
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                    justify_content: JustifyContent::Center,
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                    border: UiRect::all(Val::Px(2.)),
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                    margin: UiRect::horizontal(Val::Px(2.)),
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                    ..Default::default()
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                },
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                border_color: if active {
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                    ACTIVE_BORDER_COLOR
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                } else {
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                    INACTIVE_BORDER_COLOR
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                }
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                .into(),
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                ..Default::default()
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            },
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            constraint,
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            action,
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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(100.),
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                        justify_content: JustifyContent::Center,
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                        ..Default::default()
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                    },
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                    background_color: if active {
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                        ACTIVE_INNER_COLOR
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                    } else {
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                        INACTIVE_INNER_COLOR
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                    }
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                    .into(),
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                    ..Default::default()
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                })
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                .with_child((
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                    Text::new(label),
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                    TextStyle {
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                        color: if active {
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                            ACTIVE_TEXT_COLOR
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                        } else {
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                            UNHOVERED_TEXT_COLOR
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                        },
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                        ..text_style
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                    },
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                    TextLayout::new_with_justify(JustifyText::Center),
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                ));
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        });
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}
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fn update_buttons(
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    mut button_query: Query<
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        (Entity, &Interaction, &Constraint, &ButtonValue),
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        Changed<Interaction>,
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    >,
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    mut bar_query: Query<&mut Style, With<Bar>>,
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    mut text_query: Query<&mut TextStyle>,
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    children_query: Query<&Children>,
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    mut button_activated_event: EventWriter<ButtonActivatedEvent>,
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) {
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    let mut style = bar_query.single_mut();
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    for (button_id, interaction, constraint, value) in button_query.iter_mut() {
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        match interaction {
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            Interaction::Pressed => {
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                button_activated_event.send(ButtonActivatedEvent(button_id));
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                match constraint {
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                    Constraint::FlexBasis => {
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                        style.flex_basis = value.0;
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                    }
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                    Constraint::Width => {
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                        style.width = value.0;
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                    }
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                    Constraint::MinWidth => {
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                        style.min_width = value.0;
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                    }
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                    Constraint::MaxWidth => {
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                        style.max_width = value.0;
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                    }
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                }
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            }
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            Interaction::Hovered => {
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                if let Ok(children) = children_query.get(button_id) {
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                    for &child in children {
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                        if let Ok(grand_children) = children_query.get(child) {
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                            for &grandchild in grand_children {
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                                if let Ok(mut style) = text_query.get_mut(grandchild) {
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                                    if style.color != ACTIVE_TEXT_COLOR {
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                                        style.color = HOVERED_TEXT_COLOR;
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                                    }
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                                }
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                            }
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                        }
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                    }
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                }
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            }
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            Interaction::None => {
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                if let Ok(children) = children_query.get(button_id) {
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                    for &child in children {
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                        if let Ok(grand_children) = children_query.get(child) {
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                            for &grandchild in grand_children {
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                                if let Ok(mut style) = text_query.get_mut(grandchild) {
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                                    if style.color != ACTIVE_TEXT_COLOR {
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                                        style.color = UNHOVERED_TEXT_COLOR;
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                                    }
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                                }
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                            }
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                        }
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                    }
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                }
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            }
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        }
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    }
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}
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fn update_radio_buttons_colors(
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    mut event_reader: EventReader<ButtonActivatedEvent>,
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    button_query: Query<(Entity, &Constraint, &Interaction)>,
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    mut border_query: Query<&mut BorderColor>,
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    mut color_query: Query<&mut BackgroundColor>,
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    mut text_query: Query<&mut TextStyle>,
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    children_query: Query<&Children>,
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) {
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    for &ButtonActivatedEvent(button_id) in event_reader.read() {
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        let (_, target_constraint, _) = button_query.get(button_id).unwrap();
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        for (id, constraint, interaction) in button_query.iter() {
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            if target_constraint == constraint {
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                let (border_color, inner_color, text_color) = if id == button_id {
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                    (ACTIVE_BORDER_COLOR, ACTIVE_INNER_COLOR, ACTIVE_TEXT_COLOR)
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                } else {
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                    (
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                        INACTIVE_BORDER_COLOR,
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                        INACTIVE_INNER_COLOR,
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                        if matches!(interaction, Interaction::Hovered) {
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                            HOVERED_TEXT_COLOR
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                        } else {
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                            UNHOVERED_TEXT_COLOR
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                        },
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                    )
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                };
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                border_query.get_mut(id).unwrap().0 = border_color;
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                for &child in children_query.get(id).into_iter().flatten() {
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                    color_query.get_mut(child).unwrap().0 = inner_color;
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                    for &grandchild in children_query.get(child).into_iter().flatten() {
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                        if let Ok(mut style) = text_query.get_mut(grandchild) {
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                            style.color = text_color;
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                        }
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                    }
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                }
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            }
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        }
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    }
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}
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