fix: Fix the problems with float precisions in triangulation process

[Czaki]

Same as napari/bermuda#225

Summary by CodeRabbit

• Bug Fixes
  • Improved triangulation accuracy for large or closely spaced coordinates, reducing incorrect handling of point orientation and segment intersections.
  • Added coverage for a multi-hole polygon to verify that triangulated area remains accurate with single-precision input.

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ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Advanced

Run ID: 221b7681-67d6-463e-9750-52427e925e45

📥 Commits

Reviewing files that changed from the base of the PR and between 37f29a7 and d1573e3.

📒 Files selected for processing (3)

• src/PartSegCore_compiled_backend/triangulation/intersection.hpp
• src/tests/data/create_holes_triangulation_failure.txt
• src/tests/test_triangulate.py

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📝 Walkthrough

Walkthrough

Intersection calculations now promote coordinate differences and coefficients to double precision. A regression test triangulates a two-hole polygon loaded as float32 and checks its summed triangle area.

Changes

Triangulation precision

Layer / File(s)	Summary
Intersection arithmetic precision src/PartSegCore_compiled_backend/triangulation/intersection.hpp	Orientation and segment intersection calculations use double-precision intermediates. Segment pairs are ordered consistently before calculation.
Two-hole polygon regression test src/tests/data/create_holes_triangulation_failure.txt, src/tests/test_triangulate.py	Add a polygon fixture with two holes and a test that triangulates it as float32. The test computes the summed triangle area using float64 coordinates and checks it against 139420612.3.

Priority: ⬇️ Low

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Bug fix

Merge Risk: ⚪ Minimal · up to d1573

No actionable merge-blocking issue was identified. Run the triangulation test as part of normal checks before merging.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 40.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 5 functions across 2 files. (1 skipped: 1…	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly identifies the main change: fixing floating-point precision problems in the triangulation process. It is related to the implementation and regression-test changes.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

Full details: Docstring Coverage

Explanation

Docstring coverage is 40.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 5 functions across 2 files. (1 skipped: 1 unsupported.)

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