text: /*=========================================================================
  
    Program:   Visualization Toolkit
    Module:    vtkPixel.h
  
    Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
    All rights reserved.
    See Copyright.txt or http://www.kitware.com/Copyright.htm for details.
  
       This software is distributed WITHOUT ANY WARRANTY; without even
       the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
       PURPOSE.  See the above copyright notice for more information.
  
  =========================================================================*/
  /**
   * @class   vtkPixel
   * @brief   a cell that represents an orthogonal quadrilateral
   *
   * vtkPixel is a concrete implementation of vtkCell to represent a 2D
   * orthogonal quadrilateral. Unlike vtkQuad, the corners are at right angles,
   * and aligned along x-y-z coordinate axes leading to large increases in
   * computational efficiency.
  */
  
  #ifndef vtkPixel_h
  #define vtkPixel_h
  
  #include "vtkCommonDataModelModule.h" // For export macro
  #include "vtkCell.h"
  
  class vtkLine;
  class vtkIncrementalPointLocator;
  
  class VTKCOMMONDATAMODEL_EXPORT vtkPixel : public vtkCell
  {
  public:
    static vtkPixel *New();
    vtkTypeMacro(vtkPixel,vtkCell);
    void PrintSelf(ostream& os, vtkIndent indent) override;
  
    //@{
    /**
     * See the vtkCell API for descriptions of these methods.
     */
    int GetCellType() override {return VTK_PIXEL;};
    int GetCellDimension() override {return 2;};
    int GetNumberOfEdges() override {return 4;};
    int GetNumberOfFaces() override {return 0;};
    vtkCell *GetEdge(int edgeId) override;
    vtkCell *GetFace(int) override {return nullptr;};
    int CellBoundary(int subId, const double pcoords[3], vtkIdList *pts) override;
    void Contour(double value, vtkDataArray *cellScalars,
                 vtkIncrementalPointLocator *locator, vtkCellArray *verts,
                 vtkCellArray *lines, vtkCellArray *polys,
                 vtkPointData *inPd, vtkPointData *outPd,
                 vtkCellData *inCd, vtkIdType cellId, vtkCellData *outCd) override;
    void Clip(double value, vtkDataArray *cellScalars,
              vtkIncrementalPointLocator *locator, vtkCellArray *polys,
              vtkPointData *inPd, vtkPointData *outPd,
              vtkCellData *inCd, vtkIdType cellId, vtkCellData *outCd,
              int insideOut) override;
    int EvaluatePosition(const double x[3], double closestPoint[3],
                         int& subId, double pcoords[3],
                         double& dist2, double weights[]) override;
    void EvaluateLocation(int& subId, const double pcoords[3], double x[3],
                          double *weights) override;
    //@}
  
    /**
     * Return the center of the triangle in parametric coordinates.
     */
    int GetParametricCenter(double pcoords[3]) override;
  
    int IntersectWithLine(const double p1[3], const double p2[3], double tol, double& t,
                          double x[3], double pcoords[3], int& subId) override;
    int Triangulate(int index, vtkIdList *ptIds, vtkPoints *pts) override;
    void Derivatives(int subId, const double pcoords[3], const double *values,
                     int dim, double *derivs) override;
    double *GetParametricCoords() override;
  
    /**
     * @deprecated Replaced by vtkPixel::InterpolateFunctions as of VTK 5.2
     */
    static void InterpolationFunctions(const double pcoords[3], double weights[4]);
    /**
     * @deprecated Replaced by vtkPixel::InterpolateDerivs as of VTK 5.2
     */
    static void InterpolationDerivs(const double pcoords[3], double derivs[8]);
    //@{
    /**
     * Compute the interpolation functions/derivatives
     * (aka shape functions/derivatives)
     */
    void InterpolateFunctions(const double pcoords[3], double weights[4]) override
    {
      vtkPixel::InterpolationFunctions(pcoords,weights);
    }
    void InterpolateDerivs(const double pcoords[3], double derivs[8]) override
    {
      vtkPixel::InterpolationDerivs(pcoords,derivs);
    }
    //@}
  
  protected:
    vtkPixel();
    ~vtkPixel() override;
  
    vtkLine *Line;
  
  private:
    vtkPixel(const vtkPixel&) = delete;
    void operator=(const vtkPixel&) = delete;
  };
  
  //----------------------------------------------------------------------------
  inline int vtkPixel::GetParametricCenter(double pcoords[3])
  {
    pcoords[0] = pcoords[1] = 0.5;
    pcoords[2] = 0.0;
    return 0;
  }
  
  #endif
  
  
  