Previously, any frames in flight (`requestAnimationFrame`) on web were
not being cancelled (`cancelAnimationFrame`) when `WebRunner::destroy`
was called. If a user called `destroy`, then immediately removed the
canvas from the DOM, eframe could panic with a "failed to find (canvas)
element by id" error message.
This PR changes two things:
- The canvas element is directly referenced everywhere it's needed
instead of being looked up by `canvas_id`[^1]
- The RAF handle is stored in `WebRunner` and `cancelAnimationFrame` is
called on it inside of `WebRunner::destroy`[^2]
[^1]: The WebGL/WGPU backends were already holding onto the canvas (and
associated GPU context), so the change is just converting all the
`get_element_by_id` lookups to retrieve the canvas from the web runner
handle.
[^2]: There is only ever one frame in flight, so we store it directly as
a scalar field.
* Follow-up to https://github.com/emilk/egui/pull/3621 and
https://github.com/emilk/egui/pull/3513
To work around a Safari limitation, we run the app logic in the event
handler of copy, cut, and mouse up and down.
Previously the output of that frame was discarded, but in this PR it is
now saved to be used in the next requestAnimationFrame.
The result is noticeable more distinct clicks on buttons (one more frame
of highlight)
Bonus: also fix auto-save of a sleeping web app
* Detect panics during initialization and show them to the user
* PanicHandler now also logs the panics
* Add example of how to call into your app from JS
* Refactor: break out AppRunner and AppRunnerRef to own files
* Hide AppRunner
* Simplify user code
* AppRunnerRef -> WebRunner
* Better docs
* Don't paint until first animation frame
* Update multiple_apps.html
* Update web demo
* Cleanup and fixes
* left-align panic message in html
