336fddb101
# Objective In Bevy 0.13, `BackgroundColor` simply tinted the image of any `UiImage`. This was confusing: in every other case (e.g. Text), this added a solid square behind the element. #11165 changed this, but removed `BackgroundColor` from `ImageBundle` to avoid confusion, since the semantic meaning had changed. However, this resulted in a serious UX downgrade / inconsistency, as this behavior was no longer part of the bundle (unlike for `TextBundle` or `NodeBundle`), leaving users with a relatively frustrating upgrade path. Additionally, adding both `BackgroundColor` and `UiImage` resulted in a bizarre effect, where the background color was seemingly ignored as it was covered by a solid white placeholder image. Fixes #13969. ## Solution Per @viridia's design: > - if you don't specify a background color, it's transparent. > - if you don't specify an image color, it's white (because it's a multiplier). > - if you don't specify an image, no image is drawn. > - if you specify both a background color and an image color, they are independent. > - the background color is drawn behind the image (in whatever pixels are transparent) As laid out by @benfrankel, this involves: 1. Changing the default `UiImage` to use a transparent texture but a pure white tint. 2. Adding `UiImage::solid_color` to quickly set placeholder images. 3. Changing the default `BorderColor` and `BackgroundColor` to transparent. 4. Removing the default overrides for these values in the other assorted UI bundles. 5. Adding `BackgroundColor` back to `ImageBundle` and `ButtonBundle`. 6. Adding a 1x1 `Image::transparent`, which can be accessed from `Assets<Image>` via the `TRANSPARENT_IMAGE_HANDLE` constant. Huge thanks to everyone who helped out with the design in the linked issue and [the Discord thread](https://discord.com/channels/691052431525675048/1255209923890118697/1255209999278280844): this was very much a joint design. @cart helped me figure out how to set the UiImage's default texture to a transparent 1x1 image, which is a much nicer fix. ## Testing I've checked the examples modified by this PR, and the `ui` example as well just to be sure. ## Migration Guide - `BackgroundColor` no longer tints the color of images in `ImageBundle` or `ButtonBundle`. Set `UiImage::color` to tint images instead. - The default texture for `UiImage` is now a transparent white square. Use `UiImage::solid_color` to quickly draw debug images. - The default value for `BackgroundColor` and `BorderColor` is now transparent. Set the color to white manually to return to previous behavior.
87 lines
3.0 KiB
Rust
87 lines
3.0 KiB
Rust
//! This example illustrates how to use `TextureAtlases` within ui
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use bevy::{color::palettes::css::*, prelude::*, winit::WinitSettings};
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fn main() {
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App::new()
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.add_plugins(DefaultPlugins.set(
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// This sets image filtering to nearest
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// This is done to prevent textures with low resolution (e.g. pixel art) from being blurred
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// by linear filtering.
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ImagePlugin::default_nearest(),
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))
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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, increment_atlas_index)
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.run();
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}
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fn setup(
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mut commands: Commands,
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asset_server: Res<AssetServer>,
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mut texture_atlases: ResMut<Assets<TextureAtlasLayout>>,
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) {
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// Camera
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commands.spawn(Camera2dBundle::default());
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let text_style = TextStyle::default();
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let texture_handle = asset_server.load("textures/rpg/chars/gabe/gabe-idle-run.png");
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let texture_atlas = TextureAtlasLayout::from_grid(UVec2::splat(24), 7, 1, None, None);
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let texture_atlas_handle = texture_atlases.add(texture_atlas);
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// root node
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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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flex_direction: FlexDirection::Column,
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justify_content: JustifyContent::Center,
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align_items: AlignItems::Center,
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row_gap: Val::Px(text_style.font_size * 2.),
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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.spawn((
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ImageBundle {
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style: Style {
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width: Val::Px(256.),
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height: Val::Px(256.),
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..default()
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},
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image: UiImage::new(texture_handle),
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background_color: BackgroundColor(ANTIQUE_WHITE.into()),
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..default()
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},
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TextureAtlas::from(texture_atlas_handle),
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Outline::new(Val::Px(8.0), Val::ZERO, CRIMSON.into()),
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));
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parent.spawn(TextBundle::from_sections([
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TextSection::new("press ".to_string(), text_style.clone()),
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TextSection::new(
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"space".to_string(),
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TextStyle {
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color: YELLOW.into(),
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..text_style.clone()
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},
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),
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TextSection::new(" to advance frames".to_string(), text_style),
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]));
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});
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}
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fn increment_atlas_index(
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mut atlas_images: Query<&mut TextureAtlas>,
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keyboard: Res<ButtonInput<KeyCode>>,
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) {
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if keyboard.just_pressed(KeyCode::Space) {
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for mut atlas_image in &mut atlas_images {
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atlas_image.index = (atlas_image.index + 1) % 6;
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}
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}
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}
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