Port upstream earcut changes to C# (73e2f97) — 2026-07-01

[github-actions]

Upstream Sync Task

@Copilot please port the upstream changes listed below to C# and open a pull request.

New commits have been pushed to mapbox/earcut since the last sync.

Previous synced commit: 078722e
New upstream commit: 73e2f97
Full diff: mapbox/earcut@078722e...73e2f97

Upstream commits to port

• 73e2f97 v3.2.0
• 4fe001b better logo, readme updates
• fd91bce add a demo link, viz polishing
• 36b4777 document refine in readme
• 9fc19a7 add unit test coverage for refine
• e927494 viz improvements
• d36c6f5 faster drawing in viz
• 9315100 improve viz page, make it a proper fixture browser
• ae868f0 cleanup refine, reorder things a bit
• 965382e implement optional Delaunay refinement

What to port

Please port all upstream changes to C# and open a pull request. Follow the PORTING_GUIDE.md for language mapping conventions.

Key files to check in the upstream diff:

• src/earcut.js → port any algorithm changes to src/Earcut/Earcut.cs
• test/fixtures/*.json → copy any new/changed fixtures to test/Earcut.Tests/fixtures/
• test/expected.json → update test/Earcut.Tests/expected.json to match

After porting:

1. Run dotnet test and ensure all tests pass
2. Update PORTING_GUIDE.md if new language patterns were introduced