API reference

Triangulator Object

Polygon triangulation with hole support using the earcut algorithm.

Clean Kotlin implementation of the Mapbox earcut algorithm with extended robustness for bad input data (collinear vertices, self-touching contours, touching holes, degenerate geometry from font curve approximation).

Features:

Circular doubly-linked list with z-order spatial hashing for efficient point-in-triangle queries
David Eberly's algorithm for finding bridge vertices between holes and outer polygon
Multi-pass recovery: filter collinear → cure local intersections → split polygon
Automatic winding correction (outer → CCW, holes → CW in output)

Reference: https://github.com/mapbox/earcut

Signature

object Triangulator

Methods

signedArea ( points )

Computes the signed area of a polygon using the shoelace formula. Positive = CCW.

Signature

fun signedArea(points: List<Point2D>): Float

Parameters

points: List<Point2D>

Returns

Float

triangulate ( outer , holes )

Triangulates a polygon that may contain holes.

The outer boundary and holes are pre-classified by the caller (typically using the even-odd fill rule). Winding is auto-corrected internally.

Signature

fun triangulate(outer: List<Point2D>, holes: List<List<Point2D>> = emptyList()): TriangulationResult

Parameters

outer: List<Point2D> Vertices of the outer boundary

holes: List<List<Point2D>> List of hole boundaries (inner contours)

Returns

TriangulationResult Merged vertex list and triangle index triplets. Indices reference positions in the merged list (outer vertices first, then hole vertices in order).