vtkMarchingSquares.cxx

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

  Program:   Visualization Toolkit
  Module:    vtkMarchingSquares.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 "vtkMarchingSquares.h"

#include "vtkCellArray.h"
#include "vtkCharArray.h"
#include "vtkDoubleArray.h"
#include "vtkFloatArray.h"
#include "vtkInformation.h"
#include "vtkInformationVector.h"
#include "vtkIntArray.h"
#include "vtkLongArray.h"
#include "vtkMarchingSquaresLineCases.h"
#include "vtkMergePoints.h"
#include "vtkObjectFactory.h"
#include "vtkPointData.h"
#include "vtkPolyData.h"
#include "vtkShortArray.h"
#include "vtkStructuredPoints.h"
#include "vtkUnsignedCharArray.h"
#include "vtkUnsignedIntArray.h"
#include "vtkUnsignedLongArray.h"
#include "vtkUnsignedShortArray.h"
#include "vtkIncrementalPointLocator.h"

#include <cmath>

vtkStandardNewMacro(vtkMarchingSquares);

// Description:
// Construct object with initial scalar range (0,1) and single contour value
// of 0.0. The ImageRange are set to extract the first k-plane.
vtkMarchingSquares::vtkMarchingSquares()
{
  this->ContourValues = vtkContourValues::New();

  this->ImageRange[0] = 0; this->ImageRange[1] = VTK_INT_MAX;
  this->ImageRange[2] = 0; this->ImageRange[3] = VTK_INT_MAX;
  this->ImageRange[4] = 0; this->ImageRange[5] = 0;

  this->Locator = NULL;
}

vtkMarchingSquares::~vtkMarchingSquares()
{
  this->ContourValues->Delete();
  if ( this->Locator )
    {
    this->Locator->UnRegister(this);
    this->Locator = NULL;
    }
}

void vtkMarchingSquares::SetImageRange(int imin, int imax, int jmin, int jmax,
                                       int kmin, int kmax)
{
  int dim[6];

  dim[0] = imin;
  dim[1] = imax;
  dim[2] = jmin;
  dim[3] = jmax;
  dim[4] = kmin;
  dim[5] = kmax;

  this->SetImageRange(dim);
}

// Description:
// Overload standard modified time function. If contour values are modified,
// then this object is modified as well.
unsigned long vtkMarchingSquares::GetMTime()
{
  unsigned long mTime=this->Superclass::GetMTime();
  unsigned long mTime2=this->ContourValues->GetMTime();

  mTime = ( mTime2 > mTime ? mTime2 : mTime );
  if (this->Locator)
    {
    mTime2=this->Locator->GetMTime();
    mTime = ( mTime2 > mTime ? mTime2 : mTime );
    }

  return mTime;
}

//
// Contouring filter specialized for images
//
template <class T>
void vtkContourImage(T *scalars, vtkDataArray *newScalars, int roi[6], int dir[3],
                     int start[2], int end[2], int offset[3], double ar[3],
                     double origin[3], double *values, int numValues,
                     vtkIncrementalPointLocator *p, vtkCellArray *lines)
{
  int i, j;
  vtkIdType ptIds[2];
  double t, *x1, *x2, x[3], xp, yp;
  double pts[4][3], min, max;
  int contNum, jOffset, idx, ii, jj, index, *vert;
  static int CASE_MASK[4] = {1,2,8,4};
  vtkMarchingSquaresLineCases *lineCase, *lineCases;
  static int edges[4][2] = { {0,1}, {1,3}, {2,3}, {0,2} };
  EDGE_LIST  *edge;
  double value, s[4];

  lineCases = vtkMarchingSquaresLineCases::GetCases();
//
// Get min/max contour values
//
  if ( numValues < 1 )
    {
    return;
    }
  for ( min=max=values[0], i=1; i < numValues; i++)
    {
    if ( values[i] < min )
      {
      min = values[i];
      }
    if ( values[i] > max )
      {
      max = values[i];
      }
    }

  //assign coordinate value to non-varying coordinate direction
  x[dir[2]] = origin[dir[2]] + roi[dir[2]*2]*ar[dir[2]];

  // Traverse all pixel cells, generating line segements using marching squares.
  for ( j=roi[start[1]]; j < roi[end[1]]; j++ )
    {

    jOffset = j * offset[1];
    pts[0][dir[1]] = origin[dir[1]] + j*ar[dir[1]];
    yp = origin[dir[1]] + (j+1)*ar[dir[1]];

    for ( i=roi[start[0]]; i < roi[end[0]]; i++)
      {
       //get scalar values
      idx = i * offset[0] + jOffset + offset[2];
      s[0] = scalars[idx];
      s[1] = scalars[idx+offset[0]];
      s[2] = scalars[idx + offset[1]];
      s[3] = scalars[idx+offset[0] + offset[1]];

      if ( (s[0] < min && s[1] < min && s[2] < min && s[3] < min) ||
      (s[0] > max && s[1] > max && s[2] > max && s[3] > max) )
        {
        continue; // no contours possible
        }

      //create pixel points
      pts[0][dir[0]] = origin[dir[0]] + i*ar[dir[0]];
      xp = origin[dir[0]] + (i+1)*ar[dir[0]];

      pts[1][dir[0]] = xp;
      pts[1][dir[1]] = pts[0][dir[1]];

      pts[2][dir[0]] = pts[0][dir[0]];
      pts[2][dir[1]] = yp;

      pts[3][dir[0]] = xp;
      pts[3][dir[1]] = yp;

      // Loop over contours in this pixel
      for (contNum=0; contNum < numValues; contNum++)
        {
        value = values[contNum];

        // Build the case table
        for ( ii=0, index = 0; ii < 4; ii++)
          {
          if ( s[ii] >= value )
            {
            index |= CASE_MASK[ii];
            }
          }
        if ( index == 0 || index == 15 )
          {
          continue; //no lines
          }

        lineCase = lineCases + index;
        edge = lineCase->edges;

        for ( ; edge[0] > -1; edge += 2 )
          {
          for (ii=0; ii<2; ii++) //insert line
            {
            vert = edges[edge[ii]];
            t = (value - s[vert[0]]) / (s[vert[1]] - s[vert[0]]);
            x1 = pts[vert[0]];
            x2 = pts[vert[1]];
            for (jj=0; jj<2; jj++) //only need to interpolate two values
              {
              x[dir[jj]] = x1[dir[jj]] + t * (x2[dir[jj]] - x1[dir[jj]]);
              }
            if ( p->InsertUniquePoint(x, ptIds[ii]) )
              {
              newScalars->InsertComponent(ptIds[ii],0,value);
              }
            }

          if ( ptIds[0] != ptIds[1] ) //check for degenerate line
            {
            lines->InsertNextCell(2,ptIds);
            }

          }//for each line
        }//for all contours
      }//for i
    }//for j
}

//
// Contouring filter specialized for images (or slices from images)
//
int vtkMarchingSquares::RequestData(
  vtkInformation *vtkNotUsed(request),
  vtkInformationVector **inputVector,
  vtkInformationVector *outputVector)
{
  // get the info objects
  vtkInformation *inInfo = inputVector[0]->GetInformationObject(0);
  vtkInformation *outInfo = outputVector->GetInformationObject(0);

  // get the input and output
  vtkImageData *input = vtkImageData::SafeDownCast(
    inInfo->Get(vtkDataObject::DATA_OBJECT()));
  vtkPolyData *output = vtkPolyData::SafeDownCast(
    outInfo->Get(vtkDataObject::DATA_OBJECT()));

  vtkPointData *pd;
  vtkPoints *newPts;
  vtkCellArray *newLines;
  vtkDataArray *inScalars;
  vtkDataArray *newScalars = NULL;
  int i, dims[3], roi[6], dataSize, dim, plane=0;
  int *ext;
  double origin[3], ar[3];
  int start[2], end[2], offset[3], dir[3], estimatedSize;
  int numContours=this->ContourValues->GetNumberOfContours();
  double *values=this->ContourValues->GetValues();

  vtkDebugMacro(<< "Executing marching squares");
//
// Initialize and check input
//
  pd=input->GetPointData();
  if (pd ==NULL)
    {
    vtkErrorMacro(<<"PointData is NULL");
    return 1;
    }
  inScalars=pd->GetScalars();
  if ( inScalars == NULL )
    {
    vtkErrorMacro(<<"Scalars must be defined for contouring");
    return 1;
    }
//
// Check dimensionality of data and get appropriate form
//
  input->GetDimensions(dims);
  ext = input->GetExtent();
  input->GetOrigin(origin);
  input->GetSpacing(ar);
  dataSize = dims[0] * dims[1] * dims[2];

  if ( input->GetDataDimension() != 2 )
    {
    for (i=0; i < 6; i++)
      {
      roi[i] = this->ImageRange[i];
      }
    }
  else
    {
    input->GetExtent(roi);
    }

  // check the final region of interest to make sure its acceptable
  for ( dim=0, i=0; i < 3; i++ )
    {
    if ( roi[2*i+1] > ext[2*i+1] )
      {
      roi[2*i+1] = ext[2*i+1];
      }
    else if ( roi[2*i+1] < ext[2*i] )
      {
      roi[2*i+1] = ext[2*i];
      }

    if ( roi[2*i] > roi[2*i+1] )
      {
      roi[2*i] = roi[2*i+1];
      }
    else if ( roi[2*i] < ext[2*i] )
      {
      roi[2*i] = ext[2*i];
      }

    if ( (roi[2*i+1]-roi[2*i]) > 0 )
      {
      dim++;
      }
    else
      {
      plane = i;
      }
    }

  if ( dim != 2 )
    {
    vtkErrorMacro(<<"Marching squares requires 2D data");
    return 1;
    }
//
// Setup indices and offsets (since can have x-y or z-plane)
//
  if ( plane == 0 ) //x-plane
    {
    start[0] = 2; end[0] = 3;
    start[1] = 4; end[1] = 5;
    offset[0] = dims[0];
    offset[1] = dims[0]*dims[1];
    offset[2] = (roi[0]-ext[0]);
    dir[0] = 1; dir[1] = 2; dir[2] = 0;
    }
  else if ( plane == 1 ) //y-plane
    {
    start[0] = 0; end[0] = 1;
    start[1] = 4; end[1] = 5;
    offset[0] = 1;
    offset[1] = dims[0]*dims[1];
    offset[2] = (roi[2]-ext[2])*dims[0];
    dir[0] = 0; dir[1] = 2; dir[2] = 1;
    }
  else //z-plane
    {
    start[0] = 0; end[0] = 1;
    start[1] = 2; end[1] = 3;
    offset[0] = 1;
    offset[1] = dims[0];
    offset[2] = (roi[4]-ext[4])*dims[0]*dims[1];
    dir[0] = 0; dir[1] = 1; dir[2] = 2;
    }
//
// Allocate necessary objects
//
  estimatedSize = (int) (numContours * sqrt((double)dims[0]*dims[1]));
  estimatedSize = estimatedSize / 1024 * 1024; //multiple of 1024
  if (estimatedSize < 1024)
    {
    estimatedSize = 1024;
    }

  newPts = vtkPoints::New();
  newPts->Allocate(estimatedSize,estimatedSize);
  newLines = vtkCellArray::New();
  newLines->Allocate(newLines->EstimateSize(estimatedSize,2));

  // locator used to merge potentially duplicate points
  if ( this->Locator == NULL )
    {
    this->CreateDefaultLocator();
    }
  this->Locator->InitPointInsertion (newPts, input->GetBounds());
  //
  // Check data type and execute appropriate function
  //
  if (inScalars->GetNumberOfComponents() == 1 )
    {
    void* scalars = inScalars->GetVoidPointer(0);
    newScalars = inScalars->NewInstance();
    newScalars->Allocate(5000, 25000);
    switch (inScalars->GetDataType())
      {
      vtkTemplateMacro(
        vtkContourImage(static_cast<VTK_TT*>(scalars),newScalars,
                        roi,dir,start,end,offset,ar,origin,
                        values,numContours,this->Locator,newLines)
        );
      }//switch
    }

  else //multiple components - have to convert
    {
    vtkDoubleArray *image = vtkDoubleArray::New();
    image->SetNumberOfComponents(inScalars->GetNumberOfComponents());
    image->SetNumberOfTuples(dataSize);
    inScalars->GetTuples(0,dataSize,image);
    newScalars = vtkFloatArray::New();
    newScalars->Allocate(5000,25000);
    double *scalars = image->GetPointer(0);
    vtkContourImage(scalars,newScalars,roi,dir,start,end,offset,ar,origin,
                    values,numContours,this->Locator,newLines);
    image->Delete();
    }

  vtkDebugMacro(<<"Created: "
               << newPts->GetNumberOfPoints() << " points, "
               << newLines->GetNumberOfCells() << " lines");
  //
  // Update ourselves.  Because we don't know up front how many lines
  // we've created, take care to reclaim memory.
  //
  output->SetPoints(newPts);
  newPts->Delete();

  output->SetLines(newLines);
  newLines->Delete();

  int idx = output->GetPointData()->AddArray(newScalars);
  output->GetPointData()->SetActiveAttribute(idx, vtkDataSetAttributes::SCALARS);
  newScalars->Delete();

  this->Locator->Initialize();
  output->Squeeze();

  return 1;
}

// Description:
// Specify a spatial locator for merging points. By default,
// an instance of vtkMergePoints is used.
void vtkMarchingSquares::SetLocator(vtkIncrementalPointLocator *locator)
{
  if ( this->Locator == locator)
    {
    return;
    }

  if ( this->Locator )
    {
    this->Locator->UnRegister(this);
    this->Locator = NULL;
    }

  if ( locator )
    {
    locator->Register(this);
    }

  this->Locator = locator;
  this->Modified();
}

void vtkMarchingSquares::CreateDefaultLocator()
{
  if ( this->Locator == NULL)
    {
    this->Locator = vtkMergePoints::New();
    }
}

int vtkMarchingSquares::FillInputPortInformation(int, vtkInformation *info)
{
  info->Set(vtkAlgorithm::INPUT_REQUIRED_DATA_TYPE(), "vtkImageData");
  return 1;
}

void vtkMarchingSquares::PrintSelf(ostream& os, vtkIndent indent)
{
  this->Superclass::PrintSelf(os,indent);

  this->ContourValues->PrintSelf(os,indent.GetNextIndent());

  os << indent << "Image Range: ( "
     << this->ImageRange[0] << ", "
     << this->ImageRange[1] << ", "
     << this->ImageRange[2] << ", "
     << this->ImageRange[3] << ", "
     << this->ImageRange[4] << ", "
     << this->ImageRange[5] << " )\n";

  if ( this->Locator )
    {
    os << indent << "Locator: " << this->Locator << "\n";
    }
  else
    {
    os << indent << "Locator: (none)\n";
    }
}