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

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

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

#include <cmath>

vtkStandardNewMacro(vtkImageMagnitude);

//------------------------------------------------------------------------------
vtkImageMagnitude::vtkImageMagnitude()
{
  this->SetNumberOfInputPorts(1);
  this->SetNumberOfOutputPorts(1);
}

int vtkImageMagnitude::RequestInformation(vtkInformation* vtkNotUsed(request),
  vtkInformationVector** vtkNotUsed(inputVector), vtkInformationVector* outputVector)
{
  vtkDataObject::SetPointDataActiveScalarInfo(outputVector->GetInformationObject(0), -1, 1);
  return 1;
}

//------------------------------------------------------------------------------
// This execute method handles boundaries.
// it handles boundaries. Pixels are just replicated to get values
// out of extent.
template <class T>
void vtkImageMagnitudeExecute(
  vtkImageMagnitude* self, vtkImageData* inData, vtkImageData* outData, int outExt[6], int id, T*)
{
  vtkImageIterator<T> inIt(inData, outExt);
  vtkImageProgressIterator<T> outIt(outData, outExt, self, id);
  float sum;

  // find the region to loop over
  int maxC = inData->GetNumberOfScalarComponents();
  int idxC;

  // Loop through output pixels
  while (!outIt.IsAtEnd())
  {
    T* inSI = inIt.BeginSpan();
    T* outSI = outIt.BeginSpan();
    T* outSIEnd = outIt.EndSpan();
    while (outSI != outSIEnd)
    {
      // now process the components
      sum = 0.0;
      for (idxC = 0; idxC < maxC; idxC++)
      {
        sum += static_cast<float>(*inSI * *inSI);
        ++inSI;
      }
      *outSI = static_cast<T>(sqrt(sum));
      ++outSI;
    }
    inIt.NextSpan();
    outIt.NextSpan();
  }
}

//------------------------------------------------------------------------------
// 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 vtkImageMagnitude::ThreadedExecute(
  vtkImageData* inData, vtkImageData* outData, int outExt[6], int id)
{
  // This is really meta data and should be set in ExecuteInformation,
  // but there are some issues to solve first.
  if (id == 0 && outData->GetPointData()->GetScalars())
  {
    outData->GetPointData()->GetScalars()->SetName("Magnitude");
  }
  vtkDebugMacro(<< "Execute: inData = " << inData << ", outData = " << outData);

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

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