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/*=========================================================================
Program: Visualization Toolkit
Module: vtkShrinkFilter.cxx
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.
=========================================================================*/
#include "vtkShrinkFilter.h"
#include "vtkCell.h"
#include "vtkCellData.h"
#include "vtkIdList.h"
#include "vtkInformation.h"
#include "vtkInformationVector.h"
#include "vtkObjectFactory.h"
#include "vtkPointData.h"
#include "vtkSmartPointer.h"
#include "vtkUnstructuredGrid.h"
vtkStandardNewMacro(vtkShrinkFilter);
//----------------------------------------------------------------------------
vtkShrinkFilter::vtkShrinkFilter()
{
this->ShrinkFactor = 0.5;
}
//----------------------------------------------------------------------------
vtkShrinkFilter::~vtkShrinkFilter()
{
}
//----------------------------------------------------------------------------
void vtkShrinkFilter::PrintSelf(ostream& os, vtkIndent indent)
{
this->Superclass::PrintSelf(os,indent);
os << indent << "Shrink Factor: " << this->ShrinkFactor << "\n";
}
//----------------------------------------------------------------------------
int vtkShrinkFilter::FillInputPortInformation(int, vtkInformation* info)
{
// This filter uses the vtkDataSet cell traversal methods so it
// suppors any data set type as input.
info->Set(vtkAlgorithm::INPUT_REQUIRED_DATA_TYPE(), "vtkDataSet");
return 1;
}
//----------------------------------------------------------------------------
int vtkShrinkFilter::RequestData(vtkInformation*,
vtkInformationVector** inputVector,
vtkInformationVector* outputVector)
{
// Get input and output data.
vtkDataSet* input = vtkDataSet::GetData(inputVector[0]);
vtkUnstructuredGrid* output = vtkUnstructuredGrid::GetData(outputVector);
// We are now executing this filter.
vtkDebugMacro("Shrinking cells");
// Skip execution if there is no input geometry.
vtkIdType numCells = input->GetNumberOfCells();
vtkIdType numPts = input->GetNumberOfPoints();
if(numCells < 1 || numPts < 1)
{
vtkDebugMacro("No data to shrink!");
return 1;
}
// Allocate working space for new and old cell point lists.
vtkSmartPointer<vtkIdList> ptIds = vtkSmartPointer<vtkIdList>::New();
vtkSmartPointer<vtkIdList> newPtIds = vtkSmartPointer<vtkIdList>::New();
ptIds->Allocate(VTK_CELL_SIZE);
newPtIds->Allocate(VTK_CELL_SIZE);
// Allocate approximately the space needed for the output cells.
output->Allocate(numCells);
// Allocate space for a new set of points.
vtkSmartPointer<vtkPoints> newPts = vtkSmartPointer<vtkPoints>::New();
newPts->Allocate(numPts*8, numPts);
// Allocate space for data associated with the new set of points.
vtkPointData* inPD = input->GetPointData();
vtkPointData* outPD = output->GetPointData();
outPD->CopyAllocate(inPD, numPts*8, numPts);
// Support progress and abort.
vtkIdType tenth = (numCells >= 10? numCells/10 : 1);
double numCellsInv = 1.0/numCells;
int abort = 0;
// Point Id map.
vtkIdType* pointMap = new vtkIdType[input->GetNumberOfPoints()];
// Traverse all cells, obtaining node coordinates. Compute "center"
// of cell, then create new vertices shrunk towards center.
for(vtkIdType cellId = 0; cellId < numCells && !abort; ++cellId)
{
// Get the list of points for this cell.
input->GetCellPoints(cellId, ptIds);
vtkIdType numIds = ptIds->GetNumberOfIds();
// Periodically update progress and check for an abort request.
if(cellId % tenth == 0)
{
this->UpdateProgress((cellId+1)*numCellsInv);
abort = this->GetAbortExecute();
}
// Compute the center of mass of the cell points.
double center[3] = {0,0,0};
for(vtkIdType i=0; i < numIds; ++i)
{
double p[3];
input->GetPoint(ptIds->GetId(i), p);
for(int j=0; j < 3; ++j)
{
center[j] += p[j];
}
}
for(int j=0; j < 3; ++j)
{
center[j] /= numIds;
}
// Create new points for this cell.
newPtIds->Reset();
for(vtkIdType i=0; i < numIds; ++i)
{
// Get the old point location.
double p[3];
input->GetPoint(ptIds->GetId(i), p);
// Compute the new point location.
double newPt[3];
for(int j=0; j < 3; ++j)
{
newPt[j] = center[j] + this->ShrinkFactor*(p[j] - center[j]);
}
// Create the new point for this cell.
vtkIdType newId = newPts->InsertNextPoint(newPt);
// Copy point data from the old point.
vtkIdType oldId = ptIds->GetId(i);
outPD->CopyData(inPD, oldId, newId);
pointMap[oldId] = newId;
}
// special handling for polyhedron cells
if (vtkUnstructuredGrid::SafeDownCast(input) &&
input->GetCellType(cellId) == VTK_POLYHEDRON)
{
vtkUnstructuredGrid::SafeDownCast(input)->GetFaceStream(cellId, newPtIds);
vtkUnstructuredGrid::ConvertFaceStreamPointIds(newPtIds, pointMap);
}
else
{
for(vtkIdType i=0; i < numIds; ++i)
{
newPtIds->InsertId(i, pointMap[ptIds->GetId(i)]);
}
}
// Store the new cell in the output.
output->InsertNextCell(input->GetCellType(cellId), newPtIds);
}
// Store the new set of points in the output.
output->SetPoints(newPts);
// Just pass cell data through because we still have the same number
// and type of cells.
output->GetCellData()->PassData(input->GetCellData());
// Avoid keeping extra memory around.
output->Squeeze();
delete [] pointMap;
return 1;
}
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