Fix disjointComponents misclassifying inner component with boundary startingPoint#145
Draft
hfutrell wants to merge 1 commit into
Draft
Fix disjointComponents misclassifying inner component with boundary startingPoint#145hfutrell wants to merge 1 commit into
hfutrell wants to merge 1 commit into
Conversation
…tartingPoint windingCountIncrementer uses strict point.x > xIntercept, so a point exactly on a boundary segment returns 0. When an inner component's startingPoint lands on another component's boundary the old code got windingCount 0 and treated it as a second outer component rather than a hole. Fix: use the midpoint of the first curve as the probe point instead of startingPoint. A curve midpoint is offset into the component's interior and avoids the boundary coincidence. The same probe is used in both the classification pass and the owner-filing pass. Adds testDisjointComponentsInnerStartingPointOnOuterBoundary to verify the fix, using an outer square and an inner triangle whose startingPoint sits exactly on the outer's left edge. Co-Authored-By: Claude <noreply@anthropic.com>
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Summary
windingCountIncrementerusesguard point.x > xIntercept(strict), so a point exactly on a boundary segment returns 0. When an inner component'sstartingPointlands precisely on another component's boundary, the old code gotwindingCount == 0and treated the inner hole as a second outer component instead of grouping it with its owner.Fix: use the midpoint of the component's first curve as the probe point instead of
startingPoint. A midpoint of a curve is offset into the interior and avoids the boundary-exclusion edge case. The same probe point is used in both the classification pass (inner vs outer) and the owner-filing pass.Test
Added
testDisjointComponentsInnerStartingPointOnOuterBoundary: an outer 100×100 square and an inner triangle whosestartingPointis at(0, 50)— exactly on the outer's left edge. Without the fix,disjointComponents()returns 2 paths; with the fix, it correctly returns 1 path with 2 components.Posted by Claude on behalf of @hfutrell.