discontinuedPackage jet_cad_floor_plan has been discontinued and replaced by jet_cad_2d_plan.

hostFrameOf function

HostFrame? hostFrameOf(WorldWall host, List<WorldWall> walls)

host's frame (spec 08 D7), among walls (any walls; classify skips host itself, degenerate walls and walls that do not join it). Null for a degenerate host (07 D2).

The caps are computed in world, as 07's outline is, then taken to the host's group-local space through host.toWorld.invert() and judged again there (07's final review I1): a local ring that is not simple and anticlockwise is replaced by the free caps computed in local space, the wall at the identity with no neighbours, and the frame falls back.

Implementation

HostFrame? hostFrameOf(WorldWall host, List<WorldWall> walls) {
  final caps = capsOf(host, walls);
  if (caps == null) return null;
  final p = host.params;
  final toLocal = host.toWorld.invert();
  var ce = [for (final q in caps.endCap) toLocal.transformPoint(q)];
  var cs = [for (final q in caps.startCap) toLocal.transformPoint(q)];
  var fellBack = caps.fellBack;
  if (!isSimpleCcw(simplifyRing([...ce, ...cs]))) {
    final free = WorldWall(host.handle, p, Transform2.identity());
    ce = cap(End(free, 1), const Free()).points;
    cs = cap(End(free, 0), const Free()).points;
    fellBack = true;
  }
  final dv = p.end - p.start;
  final (l, r) = host.offsets;
  return HostFrame._(
      p.start, p.end, dv.normalized(), dv.length, l, r, ce, cs, fellBack);
}