text: /*=========================================================================
   *
   *  Copyright NumFOCUS
   *
   *  Licensed under the Apache License, Version 2.0 (the "License");
   *  you may not use this file except in compliance with the License.
   *  You may obtain a copy of the License at
   *
   *         http://www.apache.org/licenses/LICENSE-2.0.txt
   *
   *  Unless required by applicable law or agreed to in writing, software
   *  distributed under the License is distributed on an "AS IS" BASIS,
   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *  See the License for the specific language governing permissions and
   *  limitations under the License.
   *
   *=========================================================================*/
  
  
  #include "itkFastMarchingUpwindGradientImageFilterBase.h"
  #include "itkFastMarchingReachedTargetNodesStoppingCriterion.h"
  #include "itkTextOutput.h"
  #include "itkSimpleFilterWatcher.h"
  #include "itkMath.h"
  
  // namespace{
  //// The following class is used to support callbacks
  //// on the filter in the pipeline that follows later
  // class ShowProgressObject
  //{
  // public:
  //  ShowProgressObject(itk::ProcessObject* o)
  //    {m_Process = o;}
  //  void ShowProgress()
  //    {std::cout << "Progress " << m_Process->GetProgress() << std::endl;}
  //  itk::ProcessObject::Pointer m_Process;
  //};
  //}
  
  int
  itkFastMarchingUpwindGradientBaseTest(int, char *[])
  {
  
    itk::OutputWindow::SetInstance(itk::TextOutput::New().GetPointer());
  
    // create a fastmarching object
    using PixelType = float;
    constexpr unsigned Dimension = 2;
  
    using FloatImageType = itk::Image<PixelType, Dimension>;
  
    using CriterionType = itk::FastMarchingReachedTargetNodesStoppingCriterion<FloatImageType, FloatImageType>;
  
    CriterionType::Pointer criterion = CriterionType::New();
  
    using FloatFMType = itk::FastMarchingUpwindGradientImageFilterBase<FloatImageType, FloatImageType>;
  
    FloatFMType::Pointer marcher = FloatFMType::New();
  
    //   ShowProgressObject progressWatch(marcher);
    //   itk::SimpleMemberCommand<ShowProgressObject>::Pointer command;
    //   command = itk::SimpleMemberCommand<ShowProgressObject>::New();
    //   command->SetCallbackFunction(&progressWatch,
    //                                &ShowProgressObject::ShowProgress);
    //   marcher->AddObserver( itk::ProgressEvent(), command);
  
    itk::SimpleFilterWatcher MarcherWatcher(marcher);
  
    using NodeType = FloatFMType::NodeType;
    using NodePairType = FloatFMType::NodePairType;
  
    using NodePairContainerType = FloatFMType::NodePairContainerType;
  
    // setup alive points
    NodePairContainerType::Pointer AlivePoints = NodePairContainerType::New();
  
    FloatImageType::OffsetType offset0 = { { 28, 35 } };
  
    itk::Index<2> index;
    index.Fill(0);
  
    AlivePoints->push_back(NodePairType(index + offset0, 0.));
    AlivePoints->push_back(NodePairType(index + offset0, 42.));
  
    marcher->SetAlivePoints(AlivePoints);
  
    // setup trial points
    NodePairContainerType::Pointer TrialPoints = NodePairContainerType::New();
  
    index.Fill(0);
    index += offset0;
  
    index[0] += 1;
    TrialPoints->push_back(NodePairType(index, 1.));
  
    index[0] -= 1;
    index[1] += 1;
    TrialPoints->push_back(NodePairType(index, 1.));
  
    index[0] -= 1;
    index[1] -= 1;
    TrialPoints->push_back(NodePairType(index, 1.));
  
    index[0] += 1;
    index[1] -= 1;
    TrialPoints->push_back(NodePairType(index, 1.));
  
    index.Fill(300); // this node is out of range
    TrialPoints->push_back(NodePairType(index, 42.));
  
    marcher->SetTrialPoints(TrialPoints);
  
    // specify the size of the output image
    FloatImageType::SizeType size = { { 64, 64 } };
    marcher->SetOutputSize(size);
  
    // setup a speed image of ones
    FloatImageType::Pointer    speedImage = FloatImageType::New();
    FloatImageType::RegionType region;
    region.SetSize(size);
    speedImage->SetLargestPossibleRegion(region);
    speedImage->SetBufferedRegion(region);
    speedImage->Allocate();
  
    itk::ImageRegionIterator<FloatImageType> speedIter(speedImage, speedImage->GetBufferedRegion());
  
    while (!speedIter.IsAtEnd())
    {
      speedIter.Set(1.0);
      ++speedIter;
    }
  
    //  speedImage->Print( std::cout );
    marcher->SetInput(speedImage);
  
    // check the results
    using FloatGradientImage = FloatFMType::GradientImageType;
    using GradientPixelType = FloatGradientImage::PixelType;
    FloatGradientImage::Pointer                  gradientOutput = marcher->GetGradientImage();
    itk::ImageRegionIterator<FloatGradientImage> iterator(gradientOutput, gradientOutput->GetBufferedRegion());
  
    bool passed = true;
  
    while (!iterator.IsAtEnd())
    {
      FloatGradientImage::IndexType tempIndex;
      double                        distance;
      GradientPixelType             outputPixel;
  
      tempIndex = iterator.GetIndex();
      tempIndex -= offset0;
      distance = 0.0;
      for (int j = 0; j < 2; ++j)
      {
        distance += tempIndex[j] * tempIndex[j];
      }
      distance = std::sqrt(distance);
  
      outputPixel = iterator.Get();
  
      auto outputPixelNorm = (double)outputPixel.GetNorm();
  
      if (itk::Math::AlmostEquals(distance, 0.0))
      {
        continue;
      }
  
      // for test to pass, gradient vectors must have norm = 1
      // (equal to the rhs of the Eikonal equation)
      // and must be oriented radially from the seed point
  
      double dot = 0.0;
      for (int j = 0; j < 2; ++j)
      {
        dot += tempIndex[j] / distance * outputPixel[j];
      }
  
      if ((outputPixelNorm < 0.9999) || (outputPixelNorm > 1.0001) || (dot < 0.99) || (dot > 1.01))
      {
        std::cout << iterator.GetIndex() << " ";
        std::cout << outputPixelNorm << " ";
        std::cout << dot << std::endl;
        passed = false;
      }
  
      ++iterator;
    }
  
    // Set up target points.
    // The algorithm will stop when it reaches these points.
    // This point is closest to the AlivePoint:
    constexpr FloatImageType::OffsetType offset1 = { { 50, 50 } };
    constexpr FloatImageType::OffsetType offset2 = { { 40, 40 } };
    // This point is farthest from the AlivePoint:
    constexpr FloatImageType::OffsetType          offset3 = { { 0, 0 } };
    const std::vector<FloatImageType::OffsetType> targetOffsets{ offset1, offset2, offset3 };
  
    std::vector<NodeType> TargetNodes;
    for (const auto targetOffset : targetOffsets)
    {
      TargetNodes.push_back(index + targetOffset);
    }
    criterion->SetTargetNodes(TargetNodes);
  
    // Stop the algorithm when ONE of the targets has been reached.
    criterion->SetTargetCondition(CriterionType::TargetConditionEnum::OneTarget);
  
    marcher->SetStoppingCriterion(criterion);
  
    marcher->Update();
  
    // Test streaming enumeration for FastMarchingReachedTargetNodesStoppingCriterionEnums::TargetCondition elements
    const std::set<itk::FastMarchingReachedTargetNodesStoppingCriterionEnums::TargetCondition> allTargetCondition{
      itk::FastMarchingReachedTargetNodesStoppingCriterionEnums::TargetCondition::OneTarget,
      itk::FastMarchingReachedTargetNodesStoppingCriterionEnums::TargetCondition::SomeTargets,
      itk::FastMarchingReachedTargetNodesStoppingCriterionEnums::TargetCondition::AllTargets
    };
    for (const auto & ee : allTargetCondition)
    {
      std::cout << "STREAMED ENUM VALUE FastMarchingReachedTargetNodesStoppingCriterionEnums::TargetCondition: " << ee
                << std::endl;
    }
  
    if (passed)
    {
      std::cout << "Fast Marching Upwind Gradient test passed" << std::endl;
      return EXIT_SUCCESS;
    }
    else
    {
      std::cout << "Fast Marching Upwind Gradient test failed" << std::endl;
      return EXIT_FAILURE;
    }
  }
  