# Objective
I'm working on some PRs involving our font atlases and it would be nice
to be able to test these scenarios separately to better understand the
performance tradeoffs in different situations.
## Solution
Add a `many-font-sizes` option.
The old behavior is still available by running with `--many-glyphs
--many-font-sizes`.
## Testing
`cargo run --example many_text2d --release`
`cargo run --example many_text2d --release -- --many-glyphs`
`cargo run --example many_text2d --release -- --many-font-sizes`
`cargo run --example many_text2d --release -- --many-glyphs
--many-font-sizes`
# Objective
I have an application where I'd like to measure average frame rate over
the entire life of the application, and it would be handy if I could
just configure this on the existing `FrameTimeDiagnosticsPlugin`.
Probably fixes#10948?
## Solution
Add `max_history_length` to `FrameTimeDiagnosticsPlugin`, and because
`smoothing_factor` seems to be based on history length, add that too.
## Discussion
I'm not totally sure that `DEFAULT_MAX_HISTORY_LENGTH` is a great
default for `FrameTimeDiagnosticsPlugin` (or any diagnostic?). That's
1/3 of a second at typical game frame rates. Moreover, the default print
interval for `LogDiagnosticsPlugin` is 1 second. So when the two are
combined, you are printing the average over the last third of the
duration between now and the previous print, which seems a bit wonky.
(related: #11429)
I'm pretty sure this default value discussed and the current value
wasn't totally arbitrary though.
Maybe it would be nice for `Diagnostic` to have a
`with_max_history_length_and_also_calculate_a_good_default_smoothing_factor`
method? And then make an explicit smoothing factor in
`FrameTimeDiagnosticsPlugin` optional?
Or add a `new(max_history_length: usize)` method to
`FrameTimeDiagnosticsPlugin` that sets a reasonable default
`smoothing_factor`? edit: This one seems like a no-brainer, doing it.
## Alternatives
It's really easy to roll your own `FrameTimeDiagnosticsPlugin`, but that
might not be super interoperable with, for example, third party FPS
overlays. Still, might be the right call.
## Testing
`cargo run --example many_sprites` (modified to use a custom
`max_history_length`)
## Migration Guide
`FrameTimeDiagnosticsPlugin` now contains two fields. Use
`FrameTimeDiagnosticsPlugin::default()` to match Bevy's previous
behavior or, for example, `FrameTimeDiagnosticsPlugin::new(60)` to
configure it.
# Objective
Fixes#16783
## Solution
Works around a `cosmic-text` bug or limitation by triggering a re-layout
with the calculated width from the first layout run. See linked issue.
Credit to @ickshonpe for the clever solution.
## Performance
This has a significant performance impact only on unbounded text that
are not `JustifyText::Left`, which is still a bit of a bummer because
text2d performance in 0.15.1 is already not great. But this seems better
than alignment not working.
||many_text2d nfc re|many_text2d nfc re center|
|-|-|-|
|unbounded-layout-no-fix|3.06|3.10|
|unbounded-layout-fix|3.05 ⬜ -0.2%|2.71 🟥 -12.5%|
## Testing
I added a centered text to the `text2d` example.
`cargo run --example text2d`
We should look at other text examples and stress tests. I haven't tested
as thoroughly as I would like, so help testing that this doesn't break
something in UI would be appreciated.
# Objective
Make it easier to test for `Text2d` performance regressions.
Related to #16972
## Solution
Add a new `stress_test`, based on `many_sprites` and other existing
stress tests.
The `many-glyphs` option is inspired by
https://github.com/bevyengine/bevy/issues/16901#issuecomment-2558572382.
## Testing
```bash
cargo run --release --example many_text2d -- --help
cargo run --release --example many_text2d
cargo run --release --example many_text2d -- --many_glyphs
```
etc
