getCurrentExtentNid method

double getCurrentExtentNid(int nid)

Current animated extent for the live nid. Hot-path equivalent of getCurrentExtent; resolves the chain bulk → operation-group → standalone → fullExtent. Caller must guarantee nid is live and within range.

Implementation

double getCurrentExtentNid(int nid) {
  final fullRaw = _fullExtentByNid[nid];
  final full = fullRaw < 0 ? defaultExtent : fullRaw;
  // 1. Bulk — nid-keyed mirror skips the keyOfUnchecked + Set.contains
  // probe. Under the existing pendingRemoval ⊆ members invariant the
  // mirror returns the same answer as `bulk.members.contains(key)`.
  final bulk = _bulkAnimationGroup;
  if (bulk != null && _isBulkMemberByNid[nid] != 0) {
    return full * bulk.value;
  }
  // 2. Operation group
  final opKey = _opGroupKeyByNid[nid];
  if (opKey != null) {
    final group = _operationGroups[opKey];
    if (group != null) {
      final key = _nids.keyOfUnchecked(nid);
      final member = group.members[key];
      if (member != null) {
        return member.computeExtent(group.curvedValue, full);
      }
    }
  }
  // 3. Standalone
  final animation = _standaloneByNid[nid];
  if (animation == null) return full;
  final t = animationCurve.transform(animation.progress.clamp(0.0, 1.0));
  if (animation.targetExtent == _unknownExtent) {
    return animation.type == AnimationType.entering
        ? full * t
        : full * (1.0 - t);
  }
  return lerpDouble(animation.startExtent, animation.targetExtent, t)!;
}