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All the other crates in egui have serde as an optional dependency -
which is great! But sadly egui_extras unconditionally includes it, which
adds a bunch of code to stuff that may not care for it. This PR gates
serde support behind a new `serde` feature.
This is a breaking change; if that's undesirable then we can add it as a
default feature instead, though that wouldn't match any of the other
crates.
You can now set custom tags on the `UiStack`. This allows you to write
code that is situationally aware at runtime. For instance, you could
decide wether or not a label should truncate its text depending on what
part of your ui it is in, without having to pass that info down via the
callstack.
* Closes#4534
This PR:
- Introduces `Ui::stack()`, which returns the `UiStack` structure
providing information on the current `Ui` hierarchy.
- **BREAKING**: `Ui::new()` now takes a `UiStackInfo` argument, which is
used to populate some of this `Ui`'s `UiStack`'s fields.
- **BREAKING**: `Ui::child_ui()` and `Ui::child_ui_with_id_source()` now
take an `Option<UiStackInfo>` argument, which is used to populate some
of the children `Ui`'s `UiStack`'s fields.
- New `Area::kind()` builder function, to set the `UiStackKind` value of
the `Area`'s `Ui`.
- Adds a (minimalistic) demo to egui demo (in the "Misc Demos" window).
- Adds a more thorough `test_ui_stack` test/playground demo.
TODO:
- [x] benchmarks
- [x] add example to demo
Future work:
- Add `UiStackKind` and related support for more container (e.g.
`CollapsingHeader`, etc.)
- Add a tag/property system that would allow adding arbitrary data to a
stack node. This data could then be queried by nested `Ui`s. Probably
needed for #3284.
- Add support to track columnar layouts.
---------
Co-authored-by: Emil Ernerfeldt <emil.ernerfeldt@gmail.com>
Nathan Adams
Emil Ernerfeldt
Antoine Beyeler