# Objective
Currently text is recomputed unnecessarily on any changes to its color,
which is extremely expensive.
## Solution
Split up `TextStyle` into two separate components `TextFont` and
`TextColor`.
## Testing
I added this system to `many_buttons`:
```rust
fn set_text_colors_changed(mut colors: Query<&mut TextColor>) {
    for mut text_color in colors.iter_mut() {
        text_color.set_changed();
    }
}
```
reports ~4fps on main, ~50fps with this PR.
## Migration Guide
`TextStyle` has been renamed to `TextFont` and its `color` field has
been moved to a separate component named `TextColor` which newtypes
`Color`.
		
	
			
		
			
				
	
	
		
			90 lines
		
	
	
		
			2.5 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
			
		
		
	
	
			90 lines
		
	
	
		
			2.5 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
//! This example illustrates how to resize windows, and how to respond to a window being resized.
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use bevy::{prelude::*, window::WindowResized};
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fn main() {
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    App::new()
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        .insert_resource(ResolutionSettings {
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            large: Vec2::new(1920.0, 1080.0),
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            medium: Vec2::new(800.0, 600.0),
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            small: Vec2::new(640.0, 360.0),
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        })
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        .add_plugins(DefaultPlugins)
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        .add_systems(Startup, (setup_camera, setup_ui))
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        .add_systems(Update, (on_resize_system, toggle_resolution))
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        .run();
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}
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/// Marker component for the text that displays the current resolution.
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#[derive(Component)]
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struct ResolutionText;
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/// Stores the various window-resolutions we can select between.
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#[derive(Resource)]
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struct ResolutionSettings {
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    large: Vec2,
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    medium: Vec2,
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    small: Vec2,
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}
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// Spawns the camera that draws UI
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fn setup_camera(mut commands: Commands) {
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    commands.spawn(Camera2d);
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}
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// Spawns the UI
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fn setup_ui(mut commands: Commands) {
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    // Node that fills entire background
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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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                ..default()
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            },
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            ..default()
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        })
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        // Text where we display current resolution
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        .with_child((
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            Text::new("Resolution"),
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            TextFont {
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                font_size: 42.0,
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                ..default()
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            },
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            ResolutionText,
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        ));
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}
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/// This system shows how to request the window to a new resolution
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fn toggle_resolution(
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    keys: Res<ButtonInput<KeyCode>>,
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    mut windows: Query<&mut Window>,
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    resolution: Res<ResolutionSettings>,
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) {
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    let mut window = windows.single_mut();
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    if keys.just_pressed(KeyCode::Digit1) {
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        let res = resolution.small;
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        window.resolution.set(res.x, res.y);
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    }
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    if keys.just_pressed(KeyCode::Digit2) {
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        let res = resolution.medium;
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        window.resolution.set(res.x, res.y);
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    }
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    if keys.just_pressed(KeyCode::Digit3) {
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        let res = resolution.large;
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        window.resolution.set(res.x, res.y);
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    }
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}
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/// This system shows how to respond to a window being resized.
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/// Whenever the window is resized, the text will update with the new resolution.
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fn on_resize_system(
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    mut q: Query<&mut Text, With<ResolutionText>>,
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    mut resize_reader: EventReader<WindowResized>,
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) {
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    let mut text = q.single_mut();
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    for e in resize_reader.read() {
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        // When resolution is being changed
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        **text = format!("{:.1} x {:.1}", e.width, e.height);
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    }
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}
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