Function ringContains

docs/app/js/sanddance-app.js:130615–130623

(ring, point)

    return 0;
}
function ringContains(ring, point) {
    var x = point[0], y = point[1], contains1 = -1;
    for(var i = 0, n = ring.length, j = n - 1; i < n; j = i++){
        var pi = ring[i], xi = pi[0], yi = pi[1], pj = ring[j], xj = pj[0], yj = pj[1];
        if (segmentContains(pi, pj, point)) return 0;
        if (yi > y !== yj > y && x < (xj - xi) * (y - yi) / (yj - yi) + xi) contains1 = -contains1;
    }
    return contains1;
}
function segmentContains(a, b, c) {
    var i;
    return collinear(a, b, c) && within(a[i = +(a[0] === b[0])], c[i], b[i]);