text: /*=========================================================================
   *
   *  Copyright NumFOCUS
   *
   *  Licensed under the Apache License, Version 2.0 (the "License");
   *  you may not use this file except in compliance with the License.
   *  You may obtain a copy of the License at
   *
   *         http://www.apache.org/licenses/LICENSE-2.0.txt
   *
   *  Unless required by applicable law or agreed to in writing, software
   *  distributed under the License is distributed on an "AS IS" BASIS,
   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *  See the License for the specific language governing permissions and
   *  limitations under the License.
   *
   *=========================================================================*/
  /*=========================================================================
   *
   *  Portions of this file are subject to the VTK Toolkit Version 3 copyright.
   *
   *  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
   *
   *  For complete copyright, license and disclaimer of warranty information
   *  please refer to the NOTICE file at the top of the ITK source tree.
   *
   *=========================================================================*/
  #ifndef itkPolygonCell_hxx
  #define itkPolygonCell_hxx
  #include "itkPolygonCell.h"
  
  namespace itk
  {
  /**
   * Standard CellInterface:
   */
  template <typename TCellInterface>
  void
  PolygonCell<TCellInterface>::MakeCopy(CellAutoPointer & cellPointer) const
  {
    auto * newPolygonCell = new Self;
  
    cellPointer.TakeOwnership(newPolygonCell);
    const PointIdentifier numberOfPoints = this->GetNumberOfPoints();
    if (numberOfPoints)
    {
      newPolygonCell->SetPointIds(0, numberOfPoints, this->GetPointIds());
    }
    else
    {
      newPolygonCell->ClearPoints();
      // Make sure the new cell has no points or edges
    }
  }
  
  /**
   * Standard CellInterface:
   * Get the topological dimension of this cell.
   */
  template <typename TCellInterface>
  unsigned int
  PolygonCell<TCellInterface>::GetDimension() const
  {
    return Self::CellDimension;
  }
  
  /**
   * Standard CellInterface:
   * Get the number of points required to define the cell.
   */
  template <typename TCellInterface>
  unsigned int
  PolygonCell<TCellInterface>::GetNumberOfPoints() const
  {
    return static_cast<unsigned int>(m_PointIds.size());
  }
  
  /**
   * Standard CellInterface:
   * Get the number of boundary features of the given dimension.
   */
  template <typename TCellInterface>
  typename PolygonCell<TCellInterface>::CellFeatureCount
  PolygonCell<TCellInterface>::GetNumberOfBoundaryFeatures(int dimension) const
  {
    switch (dimension)
    {
      case 0:
        return this->GetNumberOfVertices();
      case 1:
        return this->GetNumberOfEdges();
      default:
        return 0;
    }
  }
  
  /**
   * Standard CellInterface:
   * Get the boundary feature of the given dimension specified by the given
   * cell feature Id.
   * The Id can range from 0 to GetNumberOfBoundaryFeatures(dimension)-1.
   */
  template <typename TCellInterface>
  bool
  PolygonCell<TCellInterface>::GetBoundaryFeature(int                   dimension,
                                                  CellFeatureIdentifier featureId,
                                                  CellAutoPointer &     cellPointer)
  {
    switch (dimension)
    {
      case 0:
      {
        VertexAutoPointer vertexPointer;
        if (this->GetVertex(featureId, vertexPointer))
        {
          TransferAutoPointer(cellPointer, vertexPointer);
          return true;
        }
        break;
      }
      case 1:
      {
        EdgeAutoPointer edgePointer;
        if (this->GetEdge(featureId, edgePointer))
        {
          TransferAutoPointer(cellPointer, edgePointer);
          return true;
        }
        break;
      }
      default:
        break; // just fall through
    }
    cellPointer.Reset();
    return false;
  }
  
  /**
   * Standard CellInterface:
   * Set the point id list used by the cell.  It is assumed that the given
   * iterator can be incremented and safely de-referenced enough times to
   * get all the point ids needed by the cell.
   */
  template <typename TCellInterface>
  void
  PolygonCell<TCellInterface>::SetPointIds(int itkNotUsed(dummy), int num, PointIdConstIterator first)
  {
    PointIdConstIterator ii(first);
  
    m_PointIds.clear();
    for (int i = 0; i < num; ++i)
    {
      m_PointIds.push_back(*ii++);
    }
    this->BuildEdges();
  }
  
  /**
   * after input the points in order, generate the edge connections
   */
  template <typename TCellInterface>
  void
  PolygonCell<TCellInterface>::BuildEdges()
  {
    if (!m_PointIds.empty())
    {
      m_Edges.resize(m_PointIds.size());
      const auto numberOfPoints = static_cast<unsigned int>(m_PointIds.size());
      for (unsigned int i = 1; i < numberOfPoints; i++)
      {
        m_Edges[i - 1][0] = i - 1;
        m_Edges[i - 1][1] = i;
      }
      m_Edges[numberOfPoints - 1][0] = numberOfPoints - 1;
      m_Edges[numberOfPoints - 1][1] = 0;
    }
    else
    {
      m_Edges.clear();
    }
  }
  
  /**
   * Standard CellInterface:
   * Set the point id list used by the cell.  It is assumed that the given
   * iterator can be incremented and safely de-referenced enough times to
   * get all the point ids needed by the cell.
   */
  template <typename TCellInterface>
  void
  PolygonCell<TCellInterface>::SetPointIds(PointIdConstIterator first)
  {
    PointIdConstIterator ii(first);
  
    for (unsigned int i = 0; i < m_PointIds.size(); ++i)
    {
      m_PointIds[i] = *ii++;
    }
  }
  
  /**
   * Add one points to the points list
   */
  template <typename TCellInterface>
  void
  PolygonCell<TCellInterface>::AddPointId(PointIdentifier ptID)
  {
    m_PointIds.push_back(ptID);
  }
  
  /**
   * Remove one points from the points list
   */
  template <typename TCellInterface>
  void
  PolygonCell<TCellInterface>::RemovePointId(PointIdentifier ptID)
  {
    auto position = std::find(m_PointIds.begin(), m_PointIds.end(), ptID);
    if (position != m_PointIds.end())
    {
      m_PointIds.erase(position);
    }
  }
  
  /**
   * clear all the point and edge informations
   */
  template <typename TCellInterface>
  void
  PolygonCell<TCellInterface>::ClearPoints()
  {
    m_PointIds.clear();
    m_Edges.clear();
  }
  
  /**
   * Standard CellInterface:
   * Set the point id list used by the cell.  It is assumed that the range
   * of iterators [first, last) contains the correct number of points needed to
   * define the cell.  The position *last is NOT referenced, so it can safely
   * be one beyond the end of an array or other container.
   */
  template <typename TCellInterface>
  void
  PolygonCell<TCellInterface>::SetPointIds(PointIdConstIterator first, PointIdConstIterator last)
  {
    PointIdConstIterator ii(first);
  
    m_PointIds.clear();
    while (ii != last)
    {
      m_PointIds.push_back(*ii++);
    }
  
    this->BuildEdges();
  }
  
  /**
   * Standard CellInterface:
   * Set an individual point identifier in the cell.
   */
  template <typename TCellInterface>
  void
  PolygonCell<TCellInterface>::SetPointId(int localId, PointIdentifier ptId)
  {
    if (m_PointIds.size() < (unsigned int)(localId + 1))
    {
      m_PointIds.resize(localId + 1);
    }
    m_PointIds[localId] = ptId;
  }
  
  /**
   * Standard CellInterface:
   * Get a begin iterator to the list of point identifiers used by the cell.
   */
  template <typename TCellInterface>
  typename PolygonCell<TCellInterface>::PointIdIterator
  PolygonCell<TCellInterface>::PointIdsBegin()
  {
    if (!m_PointIds.empty())
    {
      return &*(m_PointIds.begin());
    }
    else
    {
      return nullptr;
    }
  }
  
  /**
   * Standard CellInterface:
   * Get a const begin iterator to the list of point identifiers used
   * by the cell.
   */
  template <typename TCellInterface>
  typename PolygonCell<TCellInterface>::PointIdConstIterator
  PolygonCell<TCellInterface>::PointIdsBegin() const
  {
    if (!m_PointIds.empty())
    {
      return &*(m_PointIds.begin());
    }
    else
    {
      return nullptr;
    }
  }
  
  /**
   * Standard CellInterface:
   * Get an end iterator to the list of point identifiers used by the cell.
   */
  template <typename TCellInterface>
  typename PolygonCell<TCellInterface>::PointIdIterator
  PolygonCell<TCellInterface>::PointIdsEnd()
  {
    if (!m_PointIds.empty())
    {
      return &m_PointIds.back() + 1;
    }
    else
    {
      return nullptr;
    }
  }
  
  /**
   * Standard CellInterface:
   * Get a const end iterator to the list of point identifiers used
   * by the cell.
   */
  template <typename TCellInterface>
  typename PolygonCell<TCellInterface>::PointIdConstIterator
  PolygonCell<TCellInterface>::PointIdsEnd() const
  {
    if (!m_PointIds.empty())
    {
      return &m_PointIds.back() + 1;
    }
    else
    {
      return nullptr;
    }
  }
  
  /**
   * Polygon-specific:
   * Get the number of vertices defining the Polygon.
   */
  template <typename TCellInterface>
  typename PolygonCell<TCellInterface>::CellFeatureCount
  PolygonCell<TCellInterface>::GetNumberOfVertices() const
  {
    return static_cast<CellFeatureCount>(m_PointIds.size());
  }
  
  /**
   * Polygon-specific:
   * Get the number of edges defined for the Polygon.
   */
  template <typename TCellInterface>
  typename PolygonCell<TCellInterface>::CellFeatureCount
  PolygonCell<TCellInterface>::GetNumberOfEdges() const
  {
    return static_cast<CellFeatureCount>(m_Edges.size());
  }
  
  /**
   * Polygon-specific:
   * Get the vertex specified by the given cell feature Id.
   * The Id can range from 0 to GetNumberOfVertices()-1.
   */
  template <typename TCellInterface>
  bool
  PolygonCell<TCellInterface>::GetVertex(CellFeatureIdentifier vertexId, VertexAutoPointer & vertexPointer)
  {
    auto * vert = new VertexType;
  
    vert->SetPointId(0, m_PointIds[vertexId]);
    vertexPointer.TakeOwnership(vert);
    return true;
  }
  
  /**
   * Polygon-specific:
   * Get the edge specified by the given cell feature Id.
   * The Id can range from 0 to GetNumberOfEdges()-1.
   */
  template <typename TCellInterface>
  bool
  PolygonCell<TCellInterface>::GetEdge(CellFeatureIdentifier edgeId, EdgeAutoPointer & edgePointer)
  {
    auto *       edge = new EdgeType;
    unsigned int max_pointId = this->GetNumberOfPoints() - 1;
  
    if (edgeId < max_pointId)
    {
      edge->SetPointId(0, m_PointIds[edgeId]);
      edge->SetPointId(1, m_PointIds[edgeId + 1]);
    }
    else if (edgeId == max_pointId)
    {
      edge->SetPointId(0, m_PointIds[max_pointId]);
      edge->SetPointId(1, m_PointIds[0]);
    }
    edgePointer.TakeOwnership(edge);
    return true;
  }
  } // end namespace itk
  
  #endif
  