vtkImageGradientMagnitude.cxx

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

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

#include "vtkDataArray.h"
#include "vtkImageData.h"
#include "vtkInformation.h"
#include "vtkInformationVector.h"
#include "vtkObjectFactory.h"
#include "vtkPointData.h"
#include "vtkStreamingDemandDrivenPipeline.h"

#include <cmath>

vtkStandardNewMacro(vtkImageGradientMagnitude);

//------------------------------------------------------------------------------
// Construct an instance of vtkImageGradientMagnitude filter.
vtkImageGradientMagnitude::vtkImageGradientMagnitude()
{
  this->SetNumberOfInputPorts(1);
  this->SetNumberOfOutputPorts(1);
  this->Dimensionality = 2;
  this->HandleBoundaries = 1;
}

//------------------------------------------------------------------------------
void vtkImageGradientMagnitude::PrintSelf(ostream& os, vtkIndent indent)
{
  this->Superclass::PrintSelf(os, indent);
  os << indent << "HandleBoundaries: " << this->HandleBoundaries << "\n";
  os << indent << "Dimensionality: " << this->Dimensionality << "\n";
}

//------------------------------------------------------------------------------
// This method is passed a region that holds the image extent of this filters
// input, and changes the region to hold the image extent of this filters
// output.
int vtkImageGradientMagnitude::RequestInformation(vtkInformation* vtkNotUsed(request),
  vtkInformationVector** inputVector, vtkInformationVector* outputVector)
{
  int extent[6];
  int idx;

  // get the info objects
  vtkInformation* outInfo = outputVector->GetInformationObject(0);
  vtkInformation* inInfo = inputVector[0]->GetInformationObject(0);

  // invalid setting, it has not been set, so default to whole Extent
  inInfo->Get(vtkStreamingDemandDrivenPipeline::WHOLE_EXTENT(), extent);

  if (!this->HandleBoundaries)
  {
    // shrink output image extent.
    for (idx = 0; idx < this->Dimensionality; ++idx)
    {
      extent[idx * 2] += 1;
      extent[idx * 2 + 1] -= 1;
    }
  }

  outInfo->Set(vtkStreamingDemandDrivenPipeline::WHOLE_EXTENT(), extent, 6);

  return 1;
}

//------------------------------------------------------------------------------
// This method computes the input extent necessary to generate the output.
int vtkImageGradientMagnitude::RequestUpdateExtent(vtkInformation* vtkNotUsed(request),
  vtkInformationVector** inputVector, vtkInformationVector* outputVector)
{
  int wholeExtent[6];
  int idx;

  // get the info objects
  vtkInformation* outInfo = outputVector->GetInformationObject(0);
  vtkInformation* inInfo = inputVector[0]->GetInformationObject(0);

  // invalid setting, it has not been set, so default to whole Extent
  inInfo->Get(vtkStreamingDemandDrivenPipeline::WHOLE_EXTENT(), wholeExtent);
  int inUExt[6];
  outInfo->Get(vtkStreamingDemandDrivenPipeline::UPDATE_EXTENT(), inUExt);

  // grow input whole extent.
  for (idx = 0; idx < this->Dimensionality; ++idx)
  {
    inUExt[idx * 2] -= 1;
    inUExt[idx * 2 + 1] += 1;
    if (this->HandleBoundaries)
    {
      // we must clip extent with whole extent is we handle boundaries.
      if (inUExt[idx * 2] < wholeExtent[idx * 2])
      {
        inUExt[idx * 2] = wholeExtent[idx * 2];
      }
      if (inUExt[idx * 2 + 1] > wholeExtent[idx * 2 + 1])
      {
        inUExt[idx * 2 + 1] = wholeExtent[idx * 2 + 1];
      }
    }
  }
  inInfo->Set(vtkStreamingDemandDrivenPipeline::UPDATE_EXTENT(), inUExt, 6);

  return 1;
}

//------------------------------------------------------------------------------
// This execute method handles boundaries.
// it handles boundaries. Pixels are just replicated to get values
// out of extent.
template <class T>
void vtkImageGradientMagnitudeExecute(vtkImageGradientMagnitude* self, vtkImageData* inData,
  T* inPtr, vtkImageData* outData, T* outPtr, int outExt[6], int id)
{
  int idxC, idxX, idxY, idxZ;
  int maxC, maxX, maxY, maxZ;
  vtkIdType inIncX, inIncY, inIncZ;
  vtkIdType outIncX, outIncY, outIncZ;
  unsigned long count = 0;
  unsigned long target;
  int axesNum;
  int* wholeExtent;
  vtkIdType inIncs[3];
  double r[3], d, sum;
  int useZMin, useZMax, useYMin, useYMax, useXMin, useXMax;
  int* inExt = inData->GetExtent();

  // find the region to loop over
  maxC = outData->GetNumberOfScalarComponents();
  maxX = outExt[1] - outExt[0];
  maxY = outExt[3] - outExt[2];
  maxZ = outExt[5] - outExt[4];
  target = static_cast<unsigned long>((maxZ + 1) * (maxY + 1) / 50.0);
  target++;

  // Get the dimensionality of the gradient.
  axesNum = self->GetDimensionality();

  // Get increments to march through data
  inData->GetContinuousIncrements(outExt, inIncX, inIncY, inIncZ);
  outData->GetContinuousIncrements(outExt, outIncX, outIncY, outIncZ);

  // The data spacing is important for computing the gradient.
  inData->GetSpacing(r);
  r[0] = 0.5 / r[0];
  r[1] = 0.5 / r[1];
  r[2] = 0.5 / r[2];

  // get some other info we need
  inData->GetIncrements(inIncs);
  wholeExtent = inData->GetExtent();

  // Move the starting pointer to the correct location.
  inPtr += (outExt[0] - inExt[0]) * inIncs[0] + (outExt[2] - inExt[2]) * inIncs[1] +
    (outExt[4] - inExt[4]) * inIncs[2];

  // Loop through output pixels
  for (idxZ = 0; idxZ <= maxZ; idxZ++)
  {
    useZMin = ((idxZ + outExt[4]) <= wholeExtent[4]) ? 0 : -inIncs[2];
    useZMax = ((idxZ + outExt[4]) >= wholeExtent[5]) ? 0 : inIncs[2];
    for (idxY = 0; !self->AbortExecute && idxY <= maxY; idxY++)
    {
      if (!id)
      {
        if (!(count % target))
        {
          self->UpdateProgress(count / (50.0 * target));
        }
        count++;
      }
      useYMin = ((idxY + outExt[2]) <= wholeExtent[2]) ? 0 : -inIncs[1];
      useYMax = ((idxY + outExt[2]) >= wholeExtent[3]) ? 0 : inIncs[1];
      for (idxX = 0; idxX <= maxX; idxX++)
      {
        useXMin = ((idxX + outExt[0]) <= wholeExtent[0]) ? 0 : -inIncs[0];
        useXMax = ((idxX + outExt[0]) >= wholeExtent[1]) ? 0 : inIncs[0];
        for (idxC = 0; idxC < maxC; idxC++)
        {
          // do X axis
          d = static_cast<double>(inPtr[useXMin]);
          d -= static_cast<double>(inPtr[useXMax]);
          d *= r[0]; // multiply by the data spacing
          sum = d * d;
          // do y axis
          d = static_cast<double>(inPtr[useYMin]);
          d -= static_cast<double>(inPtr[useYMax]);
          d *= r[1]; // multiply by the data spacing
          sum += (d * d);
          if (axesNum == 3)
          {
            // do z axis
            d = static_cast<double>(inPtr[useZMin]);
            d -= static_cast<double>(inPtr[useZMax]);
            d *= r[2]; // multiply by the data spacing
            sum += (d * d);
          }
          *outPtr = static_cast<T>(sqrt(sum));
          outPtr++;
          inPtr++;
        }
      }
      outPtr += outIncY;
      inPtr += inIncY;
    }
    outPtr += outIncZ;
    inPtr += inIncZ;
  }
}

//------------------------------------------------------------------------------
// This method contains a switch statement that calls the correct
// templated function for the input data type.  The output data
// must match input type.  This method does handle boundary conditions.
void vtkImageGradientMagnitude::ThreadedExecute(
  vtkImageData* inData, vtkImageData* outData, int outExt[6], int id)
{
  void* inPtr;
  void* outPtr = outData->GetScalarPointerForExtent(outExt);
  inPtr = inData->GetScalarPointer();

  // this filter expects that input is the same type as output.
  if (inData->GetScalarType() != outData->GetScalarType())
  {
    vtkErrorMacro(<< "Execute: input data type, " << inData->GetScalarType()
                  << ", must match out ScalarType " << outData->GetScalarType());
    return;
  }

  switch (inData->GetScalarType())
  {
    vtkTemplateMacro(vtkImageGradientMagnitudeExecute(this, inData, static_cast<VTK_TT*>(inPtr),
      outData, static_cast<VTK_TT*>(outPtr), outExt, id));
    default:
      vtkErrorMacro(<< "Execute: Unknown ScalarType");
      return;
  }
}