ContourCreator.h

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// Copyright 2019-2020 CERN and copyright holders of ALICE O2.
// See https://alice-o2.web.cern.ch/copyright for details of the copyright holders.
// All rights not expressly granted are reserved.
//
// This software is distributed under the terms of the GNU General Public
// License v3 (GPL Version 3), copied verbatim in the file "COPYING".
//
// In applying this license CERN does not waive the privileges and immunities
// granted to it by virtue of its status as an Intergovernmental Organization
// or submit itself to any jurisdiction.
 
 
#ifndef O2_MCH_CONTOUR_CONTOURCREATOR_H
#define O2_MCH_CONTOUR_CONTOURCREATOR_H
 
#include <memory>
#include "ContourCreator.inl"
 
namespace o2
{
namespace mch
{
namespace contour
{
 
template <typename T>
Contour<T> createContour(const std::vector<Polygon<T>>& polygons)
{
  if (polygons.empty()) {
    return {};
  }
 
  if (!isCounterClockwiseOriented(polygons)) {
    throw std::invalid_argument("polygons should be oriented counterclockwise");
  }
 
  // trivial case : only one input polygon
  if (polygons.size() == 1) {
    Contour<T> trivialContour;
    trivialContour.addPolygon(polygons.front());
    return trivialContour;
  }
 
  std::vector<impl::VerticalEdge<T>> polygonVerticalEdges{impl::getVerticalEdges(polygons)};
 
  sortVerticalEdges(polygonVerticalEdges);
 
  // Initialize the segment tree that is used by the sweep() function
  std::unique_ptr<impl::Node<T>> segmentTree{impl::createSegmentTree(impl::getYPositions(polygons))};
 
  // Find the vertical edges of the merged contour. This is the meat of the algorithm...
  std::vector<impl::VerticalEdge<T>> contourVerticalEdges{impl::sweep(segmentTree.get(), polygonVerticalEdges)};
 
  // Deduce the horizontal edges from the vertical ones
  std::vector<impl::HorizontalEdge<T>> contourHorizontalEdges{impl::verticalsToHorizontals(contourVerticalEdges)};
 
  return impl::finalizeContour(contourVerticalEdges, contourHorizontalEdges);
}
 
template <typename T>
Contour<T> getEnvelop(const std::vector<Contour<T>>& list)
{
  std::vector<o2::mch::contour::Polygon<T>> polygons;
  for (const auto& c : list) {
    for (auto j = 0; j < c.size(); ++j) {
      polygons.push_back(c[j]);
    }
  }
  return createContour(polygons);
}
 
} // namespace contour
} // namespace mch
} // namespace o2
 
#endif