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/*=========================================================================
Program: Visualization Toolkit
Module: vtkDecimatePolylineFilter.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.
=========================================================================*/
// .NAME vtkDecimatePolylineFilter - reduce the number of lines in a polyline
// .SECTION Description
// vtkDecimatePolylineFilter is a filter to reduce the number of lines in a
// polyline. The algorithm functions by evaluating an error metric for each
// vertex (i.e., the distance of the vertex to a line defined from the two
// vertices on either side of the vertex). Then, these vertices are placed
// into a priority queue, and those with larger errors are deleted first.
// The decimation continues until the target reduction is reached.
//
// .SECTION Caveats
// This algorithm is a very simple implementation that overlooks some
// potential complexities. First, if a vertex is multiply connected,
// meaning that it is used by multiple polylines, then the extra
// topological constraints are ignored. Second, the error is not updated
// as vertices are deleted (similar to iteratively computing a quadric
// error metric). Thus, once calculated, the error is used to determine
// which vertices are removed. This can produce less than optimal results.
//
// .SECTION See Also
// vtkDecimate vtkDecimateProp vtkQuadricClustering vtkQuadricDecimation
#ifndef __vtkDecimatePolylineFilter_h
#define __vtkDecimatePolylineFilter_h
#include "vtkSmartPointer.h" // Needed for SP ivars
#include "vtkPolyDataAlgorithm.h"
class vtkPriorityQueue;
class VTK_GRAPHICS_EXPORT vtkDecimatePolylineFilter : public vtkPolyDataAlgorithm
{
public:
// Description:
// Standard methods for type information and printing.
vtkTypeMacro(vtkDecimatePolylineFilter,vtkPolyDataAlgorithm);
void PrintSelf(ostream& os, vtkIndent indent);
// Description:
// Instantiate this object with a target reduction of 0.90.
static vtkDecimatePolylineFilter *New();
// Description:
// Specify the desired reduction in the total number of polygons (e.g., if
// TargetReduction is set to 0.9, this filter will try to reduce the data set
// to 10% of its original size).
vtkSetClampMacro(TargetReduction,double,0.0,1.0);
vtkGetMacro(TargetReduction,double);
protected:
vtkDecimatePolylineFilter();
~vtkDecimatePolylineFilter();
int RequestData(vtkInformation *, vtkInformationVector **, vtkInformationVector *);
double ComputeError( vtkPolyData* input, int prev, int id, int next );
void UpdateError( vtkPolyData* input, int iId );
int GetPrev( int iId );
int GetNext( int iId );
struct vtkDecimatePolylineVertexErrorSTLMap;
vtkDecimatePolylineVertexErrorSTLMap* ErrorMap;
vtkSmartPointer< vtkPriorityQueue > PriorityQueue;
bool Closed;
double TargetReduction;
private:
vtkDecimatePolylineFilter(const vtkDecimatePolylineFilter&); // Not implemented.
void operator=(const vtkDecimatePolylineFilter&); // Not implemented.
};
#endif
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