groupRings
groupRings(
subpaths):RingGroup[]
Defined in: core/rings.ts:55
Group a flat list of closed rings into filled polygons with holes.
PathRecorder emits independent subpaths and discards which ring is an outer
boundary vs. a hole, so we recover it here: process rings largest-first; a ring
is a hole of the smallest already-seen outer that geometrically contains it,
otherwise it starts a new outer. Open or degenerate (<3 vertex) subpaths are
skipped — a fill needs a closed ring.
Limitation: single-level nesting only (no hole-within-hole islands). This covers grid cells (one ring each) and typical country polygons.
Parameters
Section titled “Parameters”subpaths
Section titled “subpaths”readonly Subpath[]