area property

Implementation

@override
double get area {
  // Mathematically beautiful Shoelace formula for polygon area.
  double sum = 0.0;
  final n = vertices.length;
  for (int i = 0; i < n; i++) {
    final j = (i + 1) % n;
    sum += (vertices[i].x * vertices[j].y) - (vertices[j].x * vertices[i].y);
  }
  return (sum / 2.0).abs();
}