Function FillProjections

libs/transit/world_feed/feed_helpers.cpp:89–129

}

void FillProjections(std::vector<m2::PointD> & polyline, size_t startIndex, size_t endIndex, m2::PointD const & point,
                     double distStopsM, Direction direction, std::vector<ProjectionData> & projections)
{
  CHECK_LESS_OR_EQUAL(startIndex, endIndex, ());

  double distTravelledM = 0.0;
  // Stop can't be further from its projection to line then |maxDistFromStopM|.
  double constexpr maxDistFromStopM = 1000;

  size_t const from = direction == Direction::Forward ? startIndex : endIndex;

  auto const endCriterion = [&](size_t i) { return direction == Direction::Forward ? i < endIndex : i > startIndex; };

  auto const move = [&](size_t & i)
  {
    direction == Direction::Forward ? ++i : --i;
    CHECK_LESS_OR_EQUAL(i, polyline.size(), ());
  };

  for (size_t i = from; endCriterion(i); move(i))
  {
    auto const current = i;
    auto const prev = direction == Direction::Forward ? i - 1 : i + 1;
    auto const next = direction == Direction::Forward ? i + 1 : i - 1;

    if (i != from)
      distTravelledM += mercator::DistanceOnEarth(polyline[prev], polyline[current]);

    auto proj =
        GetProjection(polyline, current, direction, ProjectStopOnTrack(point, polyline[current], polyline[next]));
    proj.m_distFromEnding = distTravelledM + mercator::DistanceOnEarth(polyline[current], proj.m_proj);

    // The distance on the polyline between the projections of stops must not be less than the
    // shortest possible distance between the stops themselves.
    if (proj.m_distFromEnding < distStopsM)
      continue;

    if (proj.m_distFromPoint < maxDistFromStopM)
      projections.emplace_back(proj);
  }
}

std::pair<size_t, bool> PrepareNearestPointOnTrack(m2::PointD const & point,
                                                   std::optional<m2::PointD> const & prevPoint, size_t prevIndex,