fix: Merge same-net trace lines that are close together (make at the same Y or same X) (#34)

[IbrahimLaeeq]

Fixes #34.

/claim #34

ine only shifted different-net traces apart (via TraceOverlapShiftSolver); nothing pulled close same-net parallel segments together, so two traces on one net could leave the schematic as two near-parallel lines a small offset apart.

Changes

• lib/solvers/TraceCleanupSolver/mergeSameNetCloseTraces.ts (new): pure function that, for each global-conn-net, finds parallel internal segments from different traces whose perpendicular distance is below a small threshold (default 0.15) and whose parallel ranges overlap, then snaps both to the midpoint coordinate. Only internal segments (pi ∈ [1, length-3]) are touched, so pin-anchored endpoints are never moved.
• lib/solvers/TraceCleanupSolver/TraceCleanupSolver.ts: adds a "merging_same_net_traces" step between the untangling and turn-minimization phases. It runs the new merge once, then proceeds to the existing minimize/balance phases (which will simplify any redundant geometry it leaves behind).
• tests/solvers/TraceCleanupSolver/mergeSameNetCloseTraces.test.ts (new): 6 cases covering horizontal merge, vertical merge, different-net no-op, too-far no-op, endpoint-only no-op, and non-overlapping no-op.

Verification

• bunx tsc --noEmit clean.
• bun test: 63 pass / 4 skip / 0 fail (was 57/4/0; the 6 new tests are the delta). All existing example snapshots are unchanged — the new step is a no-op on current fixtures and only activates when same-net parallel segments fall within the close-together threshold.

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Verified against the repository's own test suite before submission.

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Project	Deployment	Actions	Updated (UTC)
schematic-trace-solver	Ready	Preview, Comment	May 14, 2026 6:12pm

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Adds a new trace-cleanup step that snaps parallel internal segments of same-net traces onto a shared coordinate when they are close enough, resolving the issue where same-net parallel lines remained slightly offset.

Changes:

• New mergeSameNetCloseTraces pure function that aligns nearby parallel same-net internal segments to their midpoint coordinate.
• Inserts a new "merging_same_net_traces" pipeline step into TraceCleanupSolver between untangling and turn-minimization.
• Adds unit tests covering merge, no-merge (different nets / too-far / endpoints / non-overlapping) scenarios.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
lib/solvers/TraceCleanupSolver/mergeSameNetCloseTraces.ts	New helper that groups traces by net and snaps close parallel internal segments to a midpoint coord.
lib/solvers/TraceCleanupSolver/TraceCleanupSolver.ts	Adds the new pipeline step and wires it in after untangling.
tests/solvers/TraceCleanupSolver/mergeSameNetCloseTraces.test.ts	Unit tests verifying merge/no-merge behavior.

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