AlgorithmFilter

find_package(VTK
 COMPONENTS
    CommonCore
    CommonDataModel
    CommonExecutionModel
    FiltersSources
    InfovisCore
)

#include <vtkNew.h>

#include "vtkTest.h"
#include "vtkTestAlgorithmFilter.h"

int main(int, char*[])
{
  vtkNew<vtkTest> inputTest;
  inputTest->SetValue(5.6);
  std::cout << "Input value: " << inputTest->GetValue() << std::endl;

  vtkNew<vtkTestAlgorithmFilter> filter;
  filter->SetInput(inputTest);
  filter->Update();

  vtkTest* outputTest = filter->GetOutput();
  std::cout << "Output value: " << outputTest->GetValue() << std::endl;
  std::cout << "Input value is still: " << inputTest->GetValue() << std::endl;

  return EXIT_SUCCESS;
}

#ifndef __vtkTestAlgorithmFilter_h
#define __vtkTestAlgorithmFilter_h

#include <vtkAlgorithm.h>

class vtkDataSet;
class vtkTest;

class vtkTestAlgorithmFilter : public vtkAlgorithm
{
public:
  static vtkTestAlgorithmFilter* New();
  vtkTypeMacro(vtkTestAlgorithmFilter, vtkAlgorithm);
  void PrintSelf(ostream& os, vtkIndent indent) override;

  // Description:
  // Get the output data object for a port on this algorithm.
  vtkTest* GetOutput();
  vtkTest* GetOutput(int);
  virtual void SetOutput(vtkDataObject* d);

  // Description:
  // see vtkAlgorithm for details
  virtual int ProcessRequest(vtkInformation*, vtkInformationVector**,
                             vtkInformationVector*) override;

  // this method is not recommended for use, but lots of old style filters use
  // it
  vtkDataObject* GetInput();
  vtkDataObject* GetInput(int port);
  vtkTest* GetLabelHierarchyInput(int port);

  // Description:
  // Set an input of this algorithm. You should not override these
  // methods because they are not the only way to connect a pipeline.
  // Note that these methods support old-style pipeline connections.
  // When writing new code you should use the more general
  // vtkAlgorithm::SetInputConnection().  These methods transform the
  // input index to the input port index, not an index of a connection
  // within a single port.
  void SetInput(vtkDataObject*);
  void SetInput(int, vtkDataObject*);

  // Description:
  // Add an input of this algorithm.  Note that these methods support
  // old-style pipeline connections.  When writing new code you should
  // use the more general vtkAlgorithm::AddInputConnection().  See
  // SetInput() for details.
  void AddInput(vtkDataObject*);
  void AddInput(int, vtkDataObject*);

protected:
  vtkTestAlgorithmFilter();
  ~vtkTestAlgorithmFilter();

  // Description:
  // This is called by the superclass.
  // This is the method you should override.
  virtual int RequestDataObject(vtkInformation* request,
                                vtkInformationVector** inputVector,
                                vtkInformationVector* outputVector);

  // convenience method
  virtual int RequestInformation(vtkInformation* request,
                                 vtkInformationVector** inputVector,
                                 vtkInformationVector* outputVector);

  // Description:
  // This is called by the superclass.
  // This is the method you should override.
  virtual int RequestData(vtkInformation* request,
                          vtkInformationVector** inputVector,
                          vtkInformationVector* outputVector);

  // Description:
  // This is called by the superclass.
  // This is the method you should override.
  virtual int RequestUpdateExtent(vtkInformation*, vtkInformationVector**,
                                  vtkInformationVector*);

  virtual int FillOutputPortInformation(int port,
                                        vtkInformation* info) override;
  virtual int FillInputPortInformation(int port, vtkInformation* info) override;

private:
  vtkTestAlgorithmFilter(const vtkTestAlgorithmFilter&); // Not implemented.
  void operator=(const vtkTestAlgorithmFilter&);         // Not implemented.
};

#endif

#include "vtkTestAlgorithmFilter.h"
#include "vtkTest.h"

#include <vtkCommand.h>
#include <vtkInformation.h>
#include <vtkInformationVector.h>
#include <vtkObjectFactory.h>
#include <vtkStreamingDemandDrivenPipeline.h>

vtkStandardNewMacro(vtkTestAlgorithmFilter);

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

//----------------------------------------------------------------------------
vtkTestAlgorithmFilter::~vtkTestAlgorithmFilter()
{
}

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

//----------------------------------------------------------------------------
vtkTest* vtkTestAlgorithmFilter::GetOutput()
{
  return this->GetOutput(0);
}

//----------------------------------------------------------------------------
vtkTest* vtkTestAlgorithmFilter::GetOutput(int port)
{
  return dynamic_cast<vtkTest*>(this->GetOutputDataObject(port));
}

//----------------------------------------------------------------------------
void vtkTestAlgorithmFilter::SetOutput(vtkDataObject* d)
{
  this->GetExecutive()->SetOutputData(0, d);
}

//----------------------------------------------------------------------------
vtkDataObject* vtkTestAlgorithmFilter::GetInput()
{
  return this->GetInput(0);
}

//----------------------------------------------------------------------------
vtkDataObject* vtkTestAlgorithmFilter::GetInput(int port)
{
  return this->GetExecutive()->GetInputData(port, 0);
}

//----------------------------------------------------------------------------
vtkTest* vtkTestAlgorithmFilter::GetLabelHierarchyInput(int port)
{
  return dynamic_cast<vtkTest*>(this->GetInput(port));
}

//----------------------------------------------------------------------------
int vtkTestAlgorithmFilter::ProcessRequest(vtkInformation* request,
                                           vtkInformationVector** inputVector,
                                           vtkInformationVector* outputVector)
{
  // Create an output object of the correct type.
  if (request->Has(vtkDemandDrivenPipeline::REQUEST_DATA_OBJECT()))
  {
    return this->RequestDataObject(request, inputVector, outputVector);
  }
  // generate the data
  if (request->Has(vtkDemandDrivenPipeline::REQUEST_DATA()))
  {
    return this->RequestData(request, inputVector, outputVector);
  }

  if (request->Has(vtkStreamingDemandDrivenPipeline::REQUEST_UPDATE_EXTENT()))
  {
    return this->RequestUpdateExtent(request, inputVector, outputVector);
  }

  // execute information
  if (request->Has(vtkDemandDrivenPipeline::REQUEST_INFORMATION()))
  {
    return this->RequestInformation(request, inputVector, outputVector);
  }

  return this->Superclass::ProcessRequest(request, inputVector, outputVector);
}

//----------------------------------------------------------------------------
int vtkTestAlgorithmFilter::FillOutputPortInformation(int vtkNotUsed(port),
                                                      vtkInformation* info)
{
  // now add our info
  info->Set(vtkDataObject::DATA_TYPE_NAME(), "vtkTest");
  return 1;
}

//----------------------------------------------------------------------------
int vtkTestAlgorithmFilter::FillInputPortInformation(int vtkNotUsed(port),
                                                     vtkInformation* info)
{
  info->Set(vtkAlgorithm::INPUT_REQUIRED_DATA_TYPE(), "vtkTest");
  return 1;
}

int vtkTestAlgorithmFilter::RequestDataObject(
    vtkInformation* vtkNotUsed(request),
    vtkInformationVector** vtkNotUsed(inputVector),
    vtkInformationVector* outputVector)
{
  // RequestDataObject (RDO) is an earlier pipeline pass.
  // During RDO, each filter is supposed to produce an empty data object of the
  // proper type

  vtkInformation* outInfo = outputVector->GetInformationObject(0);
  vtkTest* output =
      dynamic_cast<vtkTest*>(outInfo->Get(vtkDataObject::DATA_OBJECT()));

  if (!output)
  {
    output = vtkTest::New();
    outInfo->Set(vtkDataObject::DATA_OBJECT(), output);
    output->FastDelete();

    this->GetOutputPortInformation(0)->Set(vtkDataObject::DATA_EXTENT_TYPE(),
                                           output->GetExtentType());
  }

  return 1;
}

//----------------------------------------------------------------------------
int vtkTestAlgorithmFilter::RequestInformation(
    vtkInformation* vtkNotUsed(request),
    vtkInformationVector** vtkNotUsed(inputVector),
    vtkInformationVector* vtkNotUsed(outputVector))
{
  // do nothing let subclasses handle it
  return 1;
}

//----------------------------------------------------------------------------
int vtkTestAlgorithmFilter::RequestUpdateExtent(
    vtkInformation* vtkNotUsed(request), vtkInformationVector** inputVector,
    vtkInformationVector* vtkNotUsed(outputVector))
{
  int numInputPorts = this->GetNumberOfInputPorts();
  for (int i = 0; i < numInputPorts; i++)
  {
    int numInputConnections = this->GetNumberOfInputConnections(i);
    for (int j = 0; j < numInputConnections; j++)
    {
      vtkInformation* inputInfo = inputVector[i]->GetInformationObject(j);
      inputInfo->Set(vtkStreamingDemandDrivenPipeline::EXACT_EXTENT(), 1);
    }
  }
  return 1;
}

//----------------------------------------------------------------------------
// This is the superclasses style of Execute method.  Convert it into
// an imaging style Execute method.
int vtkTestAlgorithmFilter::RequestData(vtkInformation* vtkNotUsed(request),
                                        vtkInformationVector** inputVector,
                                        vtkInformationVector* outputVector)
{
  // Later on RequestData (RD) happens.
  // During RD each filter examines any inputs it has, then fills in that empty
  // data object with real data.

  vtkInformation* outInfo = outputVector->GetInformationObject(0);
  vtkTest* output =
      dynamic_cast<vtkTest*>(outInfo->Get(vtkDataObject::DATA_OBJECT()));

  vtkInformation* inInfo = inputVector[0]->GetInformationObject(0);
  vtkTest* input =
      dynamic_cast<vtkTest*>(inInfo->Get(vtkDataObject::DATA_OBJECT()));
  output->ShallowCopy(input);
  output->SetValue(output->GetValue() + 1.0);

  return 1;
}

//----------------------------------------------------------------------------
void vtkTestAlgorithmFilter::SetInput(vtkDataObject* input)
{
  this->SetInput(0, input);
}

//----------------------------------------------------------------------------
void vtkTestAlgorithmFilter::SetInput(int index, vtkDataObject* input)
{
  if (input)
  {
    this->SetInputDataObject(index, input);
  }
  else
  {
    // Setting a NULL input removes the connection.
    this->SetInputDataObject(index, 0);
  }
}

//----------------------------------------------------------------------------
void vtkTestAlgorithmFilter::AddInput(vtkDataObject* input)
{
  this->AddInput(0, input);
}

//----------------------------------------------------------------------------
void vtkTestAlgorithmFilter::AddInput(int index, vtkDataObject* input)
{
  if (input)
  {
    this->AddInputDataObject(index, input);
  }
}

#ifndef __vtkTest_h
#define __vtkTest_h

#include <vtkDataObject.h>

class vtkTest : public vtkDataObject
{
public:
  static vtkTest* New();
  vtkTypeMacro(vtkTest, vtkDataObject);
  void PrintSelf(ostream& os, vtkIndent indent) override;
  void ShallowCopy(vtkDataObject* t) override;

  vtkGetMacro(Value, double);
  vtkSetMacro(Value, double);

protected:
  vtkTest();
  ~vtkTest();

private:
  vtkTest(const vtkTest&);        // Not implemented.
  void operator=(const vtkTest&); // Not implemented.

  double Value;
};

#endif

#include "vtkTest.h"

#include <vtkObjectFactory.h>

vtkStandardNewMacro(vtkTest);

vtkTest::vtkTest()
{
  this->Value = 0.0;
}

vtkTest::~vtkTest()
{
}

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

void vtkTest::ShallowCopy(vtkDataObject* t)
{
  vtkTest* m = dynamic_cast<vtkTest*>(t);
  this->Value = m->GetValue();
}

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(AlgorithmFilter)

find_package(VTK COMPONENTS 
  CommonCore
)

if (NOT VTK_FOUND)
  message(FATAL_ERROR "AlgorithmFilter: Unable to find the VTK build folder.")
endif()

# Prevent a "command line is too long" failure in Windows.
set(CMAKE_NINJA_FORCE_RESPONSE_FILE "ON" CACHE BOOL "Force Ninja to use response files.")
add_executable(AlgorithmFilter MACOSX_BUNDLE AlgorithmFilter.cxx )
  target_link_libraries(AlgorithmFilter PRIVATE ${VTK_LIBRARIES}
)
# vtk_module_autoinit is needed
vtk_module_autoinit(
  TARGETS AlgorithmFilter
  MODULES ${VTK_LIBRARIES}
)

cd AlgorithmFilter/build

cmake ..

cmake -DVTK_DIR:PATH=/home/me/vtk_build ..

make

./AlgorithmFilter