egui-based view screenshotting

[emilk]

Related

• Closes https://github.com/rerun-io/rerun/issues/3941

What

Save a screenshot of a view via egui.

The previous attempt (behind a feature-flag) only captures things that were rendered with re_renderer, i.e. dit not include any egui elements, like labels.

The new approach should work with any view, anywhere.

TODO

• [ ] Merge https://github.com/emilk/egui/pull/5416
• [ ] Implement on web
• [ ] Implement save-to-disk
• [ ] Implement for all views (requires a design for the UI of this!)
• [ ] Remove feature-flag

[github-actions[bot]]

Web viewer built successfully. If applicable, you should also test it:

• [x] I have tested the web viewer

Result	Commit	Link
✅	b935f0b	https://rerun.io/viewer/pr/8258

^{Note: This comment is updated whenever you push a commit.}

[nikolausWest]

I'd the screenshot option on this menu

[Wumpf]

right click on the tab unfortunately selects the view, meaning that one can't have selection highlights on the screenshot

[emilk]

the only thing that I didn't quite get is what removes the SpaceViewRectPublisher again from the cache for a view that's hidden. But it works 🤷

egui does is for us :)