Function segmentContains

docs/tests/v2/es6/js/sanddance.js:111731–111734

(a, b, c)

}

function segmentContains(a, b, c) {
  var i;
  return collinear(a, b, c) && within(a[i = +(a[0] === b[0])], c[i], b[i]);
}

function collinear(a, b, c) {
  return (b[0] - a[0]) * (c[1] - a[1]) === (c[0] - a[0]) * (b[1] - a[1]);