**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>
# Objective
- Fixes#14826
- For context, see #15238
## Solution
Add a `GhostNode` component to `bevy_ui` and update all the relevant
systems to use it to traverse for UI children.
- [x] `ghost_hierarchy` module
- [x] Add `GhostNode`
- [x] Add `UiRootNodes` system param for iterating (ghost-aware) UI root
nodes
- [x] Add `UiChildren` system param for iterating (ghost-aware) UI
children
- [x] Update `layout::ui_layout_system`
- [x] Use ghost-aware root nodes for camera updates
- [x] Update and remove children in taffy
- [x] Initial spawn
- [x] Detect changes on nested UI children
- [x] Use ghost-aware children traversal in
`update_uinode_geometry_recursive`
- [x] Update the rest of the UI systems to use the ghost hierarchy
- [x] `stack::ui_stack_system`
- [x] `update::`
- [x] `update_clipping_system`
- [x] `update_target_camera_system`
- [x] `accessibility::calc_name`
## Testing
- [x] Added a new example `ghost_nodes` that can be used as a testbed.
- [x] Added unit tests for _some_ of the traversal utilities in
`ghost_hierarchy`
- [x] Ensure this fulfills the needs for currently known use cases
- [x] Reactivity libraries (test with `bevy_reactor`)
- [ ] Text spans (mentioned by koe [on
discord](https://discord.com/channels/691052431525675048/1285371432460881991/1285377442998915246))
---
## Performance
[See comment
below](https://github.com/bevyengine/bevy/pull/15341#issuecomment-2385456820)
## Migration guide
Any code that previously relied on `Parent`/`Children` to iterate UI
children may now want to use `bevy_ui::UiChildren` to ensure ghost nodes
are skipped, and their first descendant Nodes included.
UI root nodes may now be children of ghost nodes, which means
`Without<Parent>` might not query all root nodes. Use
`bevy_ui::UiRootNodes` where needed to iterate root nodes instead.
## Potential future work
- Benchmarking/optimizations of hierarchies containing lots of ghost
nodes
- Further exploration of UI hierarchies and markers for root nodes/leaf
nodes to create better ergonomics for things like `UiLayer` (world-space
ui)
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: UkoeHB <37489173+UkoeHB@users.noreply.github.com>
# Objective
- Fixes https://github.com/bevyengine/bevy/issues/14593.
## Solution
- Add `ViewportConversionError` and return it from viewport conversion
methods on Camera.
## Testing
- I successfully compiled and ran all changed examples.
## Migration Guide
The following methods on `Camera` now return a `Result` instead of an
`Option` so that they can provide more information about failures:
- `world_to_viewport`
- `world_to_viewport_with_depth`
- `viewport_to_world`
- `viewport_to_world_2d`
Call `.ok()` on the `Result` to turn it back into an `Option`, or handle
the `Result` directly.
---------
Co-authored-by: Lixou <82600264+DasLixou@users.noreply.github.com>
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Zachary Harrold <zac@harrold.com.au>
# Objective
`resolve_outlines_system` wasn't updated when multi-window support was
added and it always uses the size of the primary window when resolving
viewport coords, regardless of the layout's camera target.
Fixes#14945
## Solution
It's awkward to get the viewport size of the target for an individual
node without walking the tree or adding extra fields to `Node`, so I
removed `resolve_outlines_system` and instead the outline values are
updated in `ui_layout_system`.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Also bumps `accesskit_winit` to 0.22 and fixes one breaking change.
# Objective
- `accesskit` has been updated recently to 0.16!
## Solution
- Update `accesskit`, as well as `accesskit_winit`.
- [`accesskit`
changelog](552032c839/common/CHANGELOG.md (0160-2024-06-29))
- [`accesskit_winit`
changelog](552032c839/platforms/winit/CHANGELOG.md (0220-2024-06-29))
- Fix one breaking change where `Role::StaticText` has been renamed to
`Role::Label`.
## Testing
- The test suite should cover most things.
- It would be good to test this with an example, but I don't know how.
---
## Changelog
- Update `accesskit` to 0.16 and `accesskit_winit` to 0.22.
## Migration Guide
`accesskit`'s `Role::StaticText` variant has been renamed to
`Role::Label`.
# Objective
Sometimes when despawning a ui node in the PostUpdate schedule it
panics. This is because both a despawn command and insert command are
being run on the same entity.
See this example code:
```rs
use bevy::{prelude::*, ui::UiSystem};
#[derive(Resource)]
struct SliceSquare(Handle<Image>);
fn main() {
App::new()
.add_plugins(DefaultPlugins)
.add_systems(Startup, setup)
.add_systems(Update, create_ui)
.add_systems(PostUpdate, despawn_nine_slice.after(UiSystem::Layout))
.run();
}
fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
commands.spawn(Camera2dBundle::default());
commands.insert_resource(SliceSquare(asset_server.load("textures/slice_square.png")));
}
fn create_ui(mut commands: Commands, slice_square: Res<SliceSquare>) {
commands.spawn((
NodeBundle {
style: Style {
width: Val::Px(200.),
height: Val::Px(200.),
..default()
},
background_color: Color::WHITE.into(),
..default()
},
UiImage::new(slice_square.0.clone()),
ImageScaleMode::Sliced(TextureSlicer {
border: BorderRect::square(220.),
center_scale_mode: SliceScaleMode::Stretch,
sides_scale_mode: SliceScaleMode::Stretch,
max_corner_scale: 1.,
}),
));
}
fn despawn_nine_slice(mut commands: Commands, mut slices: Query<Entity, With<ImageScaleMode>>) {
for entity in slices.iter_mut() {
commands.entity(entity).despawn_recursive();
}
}
```
This code spawns a UiNode with a sliced image scale mode, and despawns
it in the same frame. The
bevy_ui::texture_slice::compute_slices_on_image_change system tries to
insert the ComputedTextureSlices component on that node, but that entity
is already despawned causing this error:
```md
error[B0003]: Could not insert a bundle (of type `bevy_ui::texture_slice::ComputedTextureSlices`) for entity Entity { index: 2, generation: 3 } because it doesn't
exist in this World. See: https://bevyengine.org/learn/errors/#b0003
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
Encountered a panic when applying buffers for system `bevy_ui::texture_slice::compute_slices_on_image_change`!
Encountered a panic in system `bevy_ecs::schedule::executor::apply_deferred`!
Encountered a panic in system `bevy_app::main_schedule::Main::run_main`!
```
Note that you might have to run the code a few times before this error
appears.
## Solution
Use try_insert instead of insert for non critical inserts in the bevy_ui
crate.
## Some notes
In a lot of cases it does not makes much sense to despawn ui nodes after
the layout system has finished. Except maybe if you delete the root ui
node of a tree. I personally encountered this issue in bevy `0.13.2`
with a system that was running before the layout system. And in `0.13.2`
the `compute_slices_on_image_change` system was also running before the
layout system. But now it runs after the layout system. So the only way
that this bug appears now is if you despawn ui nodes after the layout
system. So I am not 100% sure if using try_insert in this system is the
best option. But personally I still think it is better then the program
panicking.
However the `update_children_target_camera` system does still run before
the layout system. So I do think it might still be able to panic when ui
nodes are despawned before the layout system. Though I haven't been able
to verify that.
# Objective
`bevy_a11y` was impossible to integrate into some third-party projects
in part because it insisted on managing the accessibility tree on its
own.
## Solution
The changes in this PR were necessary to get `bevy_egui` working with
Bevy's AccessKit integration. They were tested on a fork of 0.11,
developed against `bevy_egui`, then ported to main and tested against
the `ui` example.
## Changelog
### Changed
* Add `bevy_a11y::ManageAccessibilityUpdates` to indicate whether the
ECS should manage accessibility tree updates.
* Add getter/setter to `bevy_a11y::AccessibilityRequested`.
* Add `bevy_a11y::AccessibilitySystem` `SystemSet` for ordering relative
to accessibility tree updates.
* Upgrade `accesskit` to v0.12.0.
### Fixed
* Correctly set initial accessibility focus to new windows on creation.
## Migration Guide
### Change direct accesses of `AccessibilityRequested` to use
`AccessibilityRequested.::get()`/`AccessibilityRequested::set()`
#### Before
```
use std::sync::atomic::Ordering;
// To access
accessibility_requested.load(Ordering::SeqCst)
// To update
accessibility_requested.store(true, Ordering::SeqCst);
```
#### After
```
// To access
accessibility_requested.get()
// To update
accessibility_requested.set(true);
```
---------
Co-authored-by: StaffEngineer <111751109+StaffEngineer@users.noreply.github.com>
# Objective
Replace instances of
```rust
for x in collection.iter{_mut}() {
```
with
```rust
for x in &{mut} collection {
```
This also changes CI to no longer suppress this lint. Note that since
this lint only shows up when using clippy in pedantic mode, it was
probably unnecessary to suppress this lint in the first place.
# Objective
Replace `Query<&T, Changed<T>>` style queries with the more efficient
`Query<Ref<T>>` form in two of the UI systems.
---
## Changelog
Replaced use of `Changed` with `Ref` in queries in the
`ui_layout_system` and `calc_bounds` UI systems.
# Objective
UIs created for Bevy cannot currently be made accessible. This PR aims to address that.
## Solution
Integrate AccessKit as a dependency, adding accessibility support to existing bevy_ui widgets.
## Changelog
### Added
* Integrate with and expose [AccessKit](https://accesskit.dev) for platform accessibility.
* Add `Label` for marking text specifically as a label for UI controls.
