Method ContainsNested

s2/loop.go:956–980

ContainsNested reports whether the given loops is contained within this loop. This function does not test for edge intersections. The two loops must meet all of the Polygon requirements; for example this implies that their boundaries may not cross or have any shared edges (although they may have sha

(other *Loop)

// boundaries may not cross or have any shared edges (although they may have
// shared vertices).
func (l *Loop) ContainsNested(other *Loop) bool {
	if !l.subregionBound.Contains(other.bound) {
		return false
	}

	// Special cases to handle either loop being empty or full.  Also bail out
	// when B has no vertices to avoid heap overflow on the vertex(1) call
	// below.  (This method is called during polygon initialization before the
	// client has an opportunity to call IsValid().)
	if l.isEmptyOrFull() || other.NumVertices() < 2 {
		return l.IsFull() || other.IsEmpty()
	}

	// We are given that A and B do not share any edges, and that either one
	// loop contains the other or they do not intersect.
	m, ok := l.findVertex(other.Vertex(1))
	if !ok {
		// Since other.vertex(1) is not shared, we can check whether A contains it.
		return l.ContainsPoint(other.Vertex(1))
	}

	// Check whether the edge order around other.Vertex(1) is compatible with
	// A containing B.
	return WedgeContains(l.Vertex(m-1), l.Vertex(m), l.Vertex(m+1), other.Vertex(0), other.Vertex(2))
}

// surfaceIntegralFloat64 computes the oriented surface integral of some quantity f(x)
// over the loop interior, given a function f(A,B,C) that returns the