ColorDisconnectedRegions

#include <vtkActor.h>
#include <vtkAppendPolyData.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkPointData.h>
#include <vtkPolyDataConnectivityFilter.h>
#include <vtkPolyDataMapper.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSphereSource.h>

int main(int, char*[])
{
  vtkNew<vtkNamedColors> colors;

  // Create some spheres.
  vtkNew<vtkSphereSource> sphereSource1;
  sphereSource1->Update();

  vtkNew<vtkSphereSource> sphereSource2;
  sphereSource2->SetCenter(5, 0, 0);
  sphereSource2->Update();

  vtkNew<vtkSphereSource> sphereSource3;
  sphereSource3->SetCenter(10, 0, 0);
  sphereSource3->Update();

  vtkNew<vtkAppendPolyData> appendFilter;
  appendFilter->AddInputConnection(sphereSource1->GetOutputPort());
  appendFilter->AddInputConnection(sphereSource2->GetOutputPort());
  appendFilter->AddInputConnection(sphereSource3->GetOutputPort());
  appendFilter->Update();

  vtkNew<vtkPolyDataConnectivityFilter> connectivityFilter;
  connectivityFilter->SetInputConnection(appendFilter->GetOutputPort());
  connectivityFilter->SetExtractionModeToAllRegions();
  connectivityFilter->ColorRegionsOn();
  connectivityFilter->Update();

  // Visualize.
  vtkNew<vtkPolyDataMapper> mapper;
  mapper->SetInputConnection(connectivityFilter->GetOutputPort());
  mapper->SetScalarRange(connectivityFilter->GetOutput()
                             ->GetPointData()
                             ->GetArray("RegionId")
                             ->GetRange());
  mapper->Update();

  vtkNew<vtkActor> actor;
  actor->SetMapper(mapper);

  vtkNew<vtkRenderer> renderer;
  renderer->AddActor(actor);
  renderer->SetBackground(colors->GetColor3d("Silver").GetData());

  vtkNew<vtkRenderWindow> renderWindow;
  renderWindow->AddRenderer(renderer);
  renderWindow->SetSize(640, 480);
  renderWindow->SetWindowName("ColorDisconnectedRegions");

  vtkNew<vtkRenderWindowInteractor> interactor;
  interactor->SetRenderWindow(renderWindow);

  renderWindow->Render();
  interactor->Start();

  return EXIT_SUCCESS;
}

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(ColorDisconnectedRegions)

find_package(VTK COMPONENTS 
)

if (NOT VTK_FOUND)
  message(FATAL_ERROR "ColorDisconnectedRegions: 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(ColorDisconnectedRegions MACOSX_BUNDLE ColorDisconnectedRegions.cxx )
  target_link_libraries(ColorDisconnectedRegions PRIVATE ${VTK_LIBRARIES}
)
# vtk_module_autoinit is needed
vtk_module_autoinit(
  TARGETS ColorDisconnectedRegions
  MODULES ${VTK_LIBRARIES}
)

cd ColorDisconnectedRegions/build

cmake ..

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

make

./ColorDisconnectedRegions