# ColorCellsWithRGB

VTKExamples/Cxx/PolyData/ColorCellsWithRGB

### Description

This example shows how to assign specific colors to individual cells of a vtkPolyData. This example stores the vtkCellData as rgb triples in a vtkUnsignedCharArray.

Seealso

The example ColorCells creates a vtkCellData with a vtkFloatArray that contains index values for a vtkLookupTable.

Other Languages

See (Java)

### Code

ColorCellsWithRGB.cxx

    #include <vtkSmartPointer.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkActor.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindowInteractor.h>

    #include <vtkMath.h>
    #include <vtkUnsignedCharArray.h>
    #include <vtkCellData.h>
    #include <vtkPolyData.h>
    #include <vtkPlaneSource.h>

    #include <vtkNamedColors.h>

    int main(int , char *[])
    {
      // Provide some geometry
      int resolutionX = 5;
      int resolutionY = 3;

      vtkSmartPointer<vtkPlaneSource> aPlane =
        vtkSmartPointer<vtkPlaneSource>::New();
      aPlane->SetXResolution(resolutionX);
      aPlane->SetYResolution(resolutionY);
      aPlane->Update();

      // Create cell data
      vtkMath::RandomSeed(8775070); // for reproducibility
      vtkSmartPointer<vtkUnsignedCharArray> cellData =
        vtkSmartPointer<vtkUnsignedCharArray>::New();
      cellData->SetNumberOfComponents(3);
      cellData->SetNumberOfTuples(aPlane->GetOutput()->GetNumberOfCells());
      for (int i = 0; i < aPlane->GetOutput()->GetNumberOfCells(); i++)
      {
        float rgb[3];
        rgb[0] = vtkMath::Random(64, 255);
        rgb[1] = vtkMath::Random(64, 255);
        rgb[2] = vtkMath::Random(64, 255);
        cellData->InsertTuple(i, rgb);
      }

      aPlane->GetOutput()->GetCellData()->SetScalars(cellData);

      // Setup actor and mapper
      vtkSmartPointer<vtkNamedColors> colors =
        vtkSmartPointer<vtkNamedColors>::New();

      vtkSmartPointer<vtkPolyDataMapper> mapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      mapper->SetInputConnection(aPlane->GetOutputPort());

      vtkSmartPointer<vtkActor> actor =
        vtkSmartPointer<vtkActor>::New();
      actor->SetMapper(mapper);

      // Setup render window, renderer, and interactor
      vtkSmartPointer<vtkRenderer> renderer =
        vtkSmartPointer<vtkRenderer>::New();
      vtkSmartPointer<vtkRenderWindow> renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();
      renderWindow->AddRenderer(renderer);
      vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
          vtkSmartPointer<vtkRenderWindowInteractor>::New();
      renderWindowInteractor->SetRenderWindow(renderWindow);
      renderer->AddActor(actor);
      renderer->SetBackground(colors->GetColor3d("SlateGray").GetData());
      renderWindow->Render();
      renderWindowInteractor->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(ColorCellsWithRGB)

    find_package(VTK COMPONENTS
      vtkCommonColor
      vtkCommonCore
      vtkCommonDataModel
      vtkFiltersSources
      vtkInteractionStyle
      vtkRenderingCore
      vtkRenderingFreeType
      vtkRenderingOpenGL2 QUIET)
    if (NOT VTK_FOUND)
      message("Skipping ColorCellsWithRGB: ${VTK_NOT_FOUND_MESSAGE}")
      return ()
    endif()
    message (STATUS "VTK_VERSION: ${VTK_VERSION}")
    if (VTK_VERSION VERSION_LESS "8.90.0")
      # old system
      include(${VTK_USE_FILE})
      add_executable(ColorCellsWithRGB MACOSX_BUNDLE ColorCellsWithRGB.cxx )
      target_link_libraries(ColorCellsWithRGB PRIVATE ${VTK_LIBRARIES})
    else ()
      # include all components
      add_executable(ColorCellsWithRGB MACOSX_BUNDLE ColorCellsWithRGB.cxx )
      target_link_libraries(ColorCellsWithRGB PRIVATE ${VTK_LIBRARIES})
      # vtk_module_autoinit is needed
      vtk_module_autoinit(
        TARGETS ColorCellsWithRGB
        MODULES ${VTK_LIBRARIES}
        )
    endif ()

### Download and Build ColorCellsWithRGB

Click here to download ColorCellsWithRGB and its CMakeLists.txt file. Once the tarball ColorCellsWithRGB.tar has been downloaded and extracted,

    cd ColorCellsWithRGB/build

If VTK is installed:

    cmake ..

If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:

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

Build the project:

    make

and run it:

    ./ColorCellsWithRGB

WINDOWS USERS

Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.