Proposal for the support of 3D meshes as object shape.

[tinevez]

Proposed Change

This PR add specifications for the support of triangular meshes as object shape in GEFF.

Types of Changes

• New feature or enhancement

Which topics does your change affect? Delete those that do not apply.

• Specification

Checklist

Put an x in the boxes that apply. You can also fill these out after creating the PR. If you're unsure about any of them, don't hesitate to ask. We're here to help! This is simply a reminder of what we are going to look for before merging your code.

• I have read the developer/contributing docs.
• I have added tests that prove that my feature works in various situations or tests the bugfix (if appropriate).
• I have checked that I maintained or improved code coverage.
• I have written docstrings and checked that they render correctly by looking at the docs preview (link left as a comment on the PR).

If you changed the specification

• I have checked that any validation functions and tests reflect the changes.
• I have updated the GeffMetadata and the json schema using pytest --update-schema if necessary.
• I have updated docs/specification.md to reflect the change.
• I have updated implementations to reflect the change. (This can happen in separate PRs on a feature branch, but must be complete before merging into main.)
• If I added a new field to GeffMetadata, I also added it to tests/geff-spec/test_schema.py test_all_fields.

If you have added or changed an implementation

• I wrote tests for the new implementation using standard fixtures supplied in conftest.py.
• I updated pyproject.toml with new dependencies if needed.
• I added a function to tests/bench.py to benchmark the new implementation.

Further Comments

See https://imagesc.zulipchat.com/#narrow/channel/517314-Live-Image-Tracking-Tools/topic/De.2FSerializing.203D.20meshes/with/618954428

[codspeed]

Merging this PR will improve performance by ×3.9

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

⚡ 1 improved benchmark
✅ 6 untouched benchmarks

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
⚡	Simulation	test_bench_read[read_sg-500]	4 s	1 s	×3.9

Tip

Curious why performance improved? Comment @codspeedbot explain why performance improved on this PR, or directly use the CodSpeed MCP with your agent.

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_{Comparing tinevez:meshes (94586f7) with main (5727ad6)}