dox/Filtering/vtkPolygon.h

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/*=========================================================================

  Program:   Visualization Toolkit
  Module:    vtkPolygon.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.

=========================================================================*/
#ifndef __vtkPolygon_h
#define __vtkPolygon_h

#include "vtkCell.h"

class vtkDoubleArray;
class vtkIdTypeArray;
class vtkLine;
class vtkPoints;
class vtkQuad;
class vtkTriangle;
class vtkIncrementalPointLocator;

class VTK_FILTERING_EXPORT vtkPolygon : public vtkCell
{
public:
  static vtkPolygon *New();
  vtkTypeMacro(vtkPolygon,vtkCell);
  void PrintSelf(ostream& os, vtkIndent indent);


  int GetCellType() {return VTK_POLYGON;};
  int GetCellDimension() {return 2;};
  int GetNumberOfEdges() {return this->GetNumberOfPoints();};
  int GetNumberOfFaces() {return 0;};
  vtkCell *GetEdge(int edgeId);
  vtkCell *GetFace(int) {return 0;};
  int CellBoundary(int subId, double pcoords[3], vtkIdList *pts);
  void Contour(double value, vtkDataArray *cellScalars,
               vtkIncrementalPointLocator *locator,vtkCellArray *verts,
               vtkCellArray *lines, vtkCellArray *polys,
               vtkPointData *inPd, vtkPointData *outPd,
               vtkCellData *inCd, vtkIdType cellId, vtkCellData *outCd);
  void Clip(double value, vtkDataArray *cellScalars,
            vtkIncrementalPointLocator *locator, vtkCellArray *tris,
            vtkPointData *inPd, vtkPointData *outPd,
            vtkCellData *inCd, vtkIdType cellId, vtkCellData *outCd,
            int insideOut);
  int EvaluatePosition(double x[3], double* closestPoint,
                       int& subId, double pcoords[3],
                       double& dist2, double *weights);
  void EvaluateLocation(int& subId, double pcoords[3], double x[3],
                        double *weights);
  int IntersectWithLine(double p1[3], double p2[3], double tol, double& t,
                        double x[3], double pcoords[3], int& subId);
  int Triangulate(int index, vtkIdList *ptIds, vtkPoints *pts);
  void Derivatives(int subId, double pcoords[3], double *values,
                   int dim, double *derivs);
  int IsPrimaryCell() {return 0;}

  double ComputeArea();


  virtual void InterpolateFunctions(double x[3], double *sf);
  virtual void InterpolateDerivs(double x[3], double *derivs);


  static void ComputeNormal(vtkPoints *p, int numPts, vtkIdType *pts,
                            double n[3]);
  static void ComputeNormal(vtkPoints *p, double n[3]);
  static void ComputeNormal(vtkIdTypeArray *ids, vtkPoints *pts, double n[3]);

  static void ComputeNormal(int numPts, double *pts, double n[3]);


  static void ComputeCentroid(vtkIdTypeArray *ids, vtkPoints *pts, 
                              double centroid[3]);

  VTK_LEGACY(void ComputeWeights(double x[3], double *weights));


  static double ComputeArea(vtkPoints *p, vtkIdType numPts, vtkIdType *pts,
                            double normal[3]);


  int ParameterizePolygon(double p0[3], double p10[3], double &l10,
                          double p20[3], double &l20, double n[3]);


  static int PointInPolygon(double x[3], int numPts, double *pts,
                            double bounds[6], double n[3]);

  int Triangulate(vtkIdList *outTris);

  int NonDegenerateTriangulate(vtkIdList *outTris);


  static double DistanceToPolygon(double x[3], int numPts, double *pts,
                                  double bounds[6], double closest[3]);


  static int IntersectPolygonWithPolygon(int npts, double *pts, double bounds[6],
                                         int npts2, double *pts2,
                                         double bounds2[3], double tol,
                                         double x[3]);


  static int IntersectConvex2DCells(vtkCell *cell1, vtkCell *cell2,
                                    double tol, double p0[3], double p1[3]);


  vtkGetMacro(UseMVCInterpolation, bool);
  vtkSetMacro(UseMVCInterpolation, bool);
  
protected:
  vtkPolygon();
  ~vtkPolygon();

  // Compute the interpolation functions using Mean Value Coordinate.
  void InterpolateFunctionsUsingMVC(double x[3], double *weights);

  // variables used by instances of this class
  double   Tolerance; // Intersection tolerance
  int      SuccessfulTriangulation; // Stops recursive tri. if necessary
  double   Normal[3]; //polygon normal
  vtkIdList *Tris;
  vtkTriangle *Triangle;
  vtkQuad *Quad;
  vtkDoubleArray *TriScalars;
  vtkLine *Line;

  // Parameter indicating whether to use Mean Value Coordinate algorithm 
  // for interpolation. The parameter is false by default.
  bool     UseMVCInterpolation;
  
  // Helper methods for triangulation------------------------------
  int EarCutTriangulation();

private:
  vtkPolygon(const vtkPolygon&);  // Not implemented.
  void operator=(const vtkPolygon&);  // Not implemented.
};

#endif

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