6f7d0e5725
# 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`.
84 lines
2.9 KiB
Rust
84 lines
2.9 KiB
Rust
//! Demonstrates how to use transparency with UI.
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//! Shows two colored buttons with transparent text.
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use bevy::prelude::*;
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fn main() {
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App::new()
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.insert_resource(ClearColor(Color::BLACK))
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.add_plugins(DefaultPlugins)
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.add_systems(Startup, setup)
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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(Camera2d);
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let font_handle = asset_server.load("fonts/FiraSans-Bold.ttf");
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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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align_items: AlignItems::Center,
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justify_content: JustifyContent::SpaceAround,
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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(ButtonBundle {
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style: Style {
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width: Val::Px(150.0),
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height: Val::Px(65.0),
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justify_content: JustifyContent::Center,
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align_items: AlignItems::Center,
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..default()
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},
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background_color: Color::srgb(0.1, 0.5, 0.1).into(),
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..default()
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})
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.with_children(|parent| {
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parent.spawn((
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Text::new("Button 1"),
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TextFont {
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font: font_handle.clone(),
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font_size: 33.0,
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..default()
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},
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// Alpha channel of the color controls transparency.
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TextColor(Color::srgba(1.0, 1.0, 1.0, 0.2)),
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));
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});
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// Button with a different color,
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// to demonstrate the text looks different due to its transparency.
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parent
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.spawn(ButtonBundle {
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style: Style {
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width: Val::Px(150.0),
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height: Val::Px(65.0),
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justify_content: JustifyContent::Center,
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align_items: AlignItems::Center,
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..default()
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},
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background_color: Color::srgb(0.5, 0.1, 0.5).into(),
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..default()
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})
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.with_children(|parent| {
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parent.spawn((
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Text::new("Button 2"),
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TextFont {
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font: font_handle.clone(),
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font_size: 33.0,
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..default()
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},
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// Alpha channel of the color controls transparency.
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TextColor(Color::srgba(1.0, 1.0, 1.0, 0.2)),
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));
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});
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});
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}
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