Add script to generate RRD vs. screenshots comparisons

[abey79]

What

This PR introduces a script that builds a local, web-based comparison between our various example code and the screenshot we provide along them, to help identify discrepancies.

❯ python scripts/screenshot_compare/build_screenshot_compare.py --help
usage: build_screenshot_compare.py [-h] [--serve] [--skip-build]
                                   [--skip-example-build]

Generate comparison between examples and their related screenshots.

This script builds/gather RRDs and corresponding screenshots and displays
them side-by-side. It pulls from the following sources:

- The screenshots listed in .fbs files (crates/re_types/definitions/rerun/**/*.fbs),
  and the corresponding code examples in the docs (docs/code-examples/*.rs)
- The `demo.rerun.io` examples, as built by the `build_demo_app.py` script.

The comparison is generated in the `compare_screenshot` directory. Use the `--serve`
option to show them in a browser.

options:
  -h, --help            show this help message and exit
  --serve               Serve the app on this port after building [default:
                        8080]
  --skip-build          Skip building the Python SDK and web viewer Wasm.
  --skip-example-build  Skip building the RRDs.

Checklist

• I have read and agree to Contributor Guide and the Code of Conduct
• I've included a screenshot or gif (if applicable)
• I have tested demo.rerun.io (if applicable)
• The PR title and labels are set such as to maximize their usefulness for the next release's CHANGELOG

• PR Build Summary
• Docs preview
• Examples preview
• Recent benchmark results
• Wasm size tracking

[jleibs]

Rather than copying all of the index business it seems like this could potentially be simplified by using a iframe pointed at app.rerun.io.

[abey79]

Rather than copying all of the index business it seems like this could potentially be simplified by using a iframe pointed at app.rerun.io.

Yeah I took all possible shortcuts here. I've copied what build_demo_app.py does without modification (nor understanding it fully tbh). I just tried to have app.rerun.io load a RRD from the local server without success—not sure what's going on. Also, I believe this script has more value by running a viewer built from main since it would typically be used during the doc update in prep of a coming release.

[teh-cmc]

Agree with @jleibs, copying all the index stuff is a bit too much.

I just tried to have app.rerun.io load a RRD from the local server without success

Not sure what you mean by "from the local server" -- the web app can load rrd files from the local disk, can't it?
EDIT: No it can't, not without going through the file dialog first.

Also, I believe this script has more value by running a viewer built from main since it would typically be used during the doc update in prep of a coming release.

We generate a hosted app.rerun.io for each PR commit (https://app.rerun.io/commit/{short_git_hash}) so an iframe would actually work great here (just pick the one from the release PR and you're set).

[jleibs]

Tested and works for me. Thanks for cleaning up to avoid the duplication:

The only confusion is when it runs the log messages:

Serving examples at http://127.0.0.1:8080/

Press enter to reload static files
[2023-10-23T15:42:49Z INFO  re_ws_comms::server] Listening for WebSocket traffic on ws://localhost:9877. Connect with a Rerun Web Viewer.
[2023-10-23T15:42:49Z INFO  re_web_viewer_server] Started web server on http://localhost:9090
[2023-10-23T15:42:49Z INFO  re_sdk::web_viewer] Web server is running - view it at http://localhost:9090?url=ws://localhost:9877

Make it a bit confusing to know which url to use.

[abey79]

The only confusion is when it runs the log messages:

Indeed. I've changed it to use a sub-process and silence the warning via the environment variables.