# 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.
# Objective
Fixes#13920
## Solution
As described in the issue.
## Testing
Moved a custom transition plugin in example before any of the app-state
methods.
# Objective
Fixes#13711
## Solution
Introduce smaller, generic system sets for each schedule variant, which
are ordered against other generic variants:
- `ExitSchedules<S>` - For `OnExit` schedules, runs from leaf states to
root states.
- `TransitionSchedules<S>` - For `OnTransition` schedules, runs in
arbitrary order.
- `EnterSchedules<S>` - For `OnEnter` schedules, runs from root states
to leaf states.
Also unified `ApplyStateTransition<S>` schedule which works in basically
the same way, just for internals.
## Testing
- One test that tests schedule execution order
---------
Co-authored-by: Lee-Orr <lee-orr@users.noreply.github.com>
# Objective
This PR addresses one of the issues from [discord state
discussion](https://discord.com/channels/691052431525675048/1237949214017716356).
Same-state transitions can be desirable, so there should exist a hook
for them.
Fixes https://github.com/bevyengine/bevy/issues/9130.
## Solution
- Allow `StateTransitionEvent<S>` to contain identity transitions.
- Ignore identity transitions at schedule running level (`OnExit`,
`OnTransition`, `OnEnter`).
- Propagate identity transitions through `SubStates` and
`ComputedStates`.
- Add example about registering custom transition schedules.
## Changelog
- `StateTransitionEvent<S>` can be emitted with same `exited` and
`entered` state.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
