ColorCellsWithRGB

VTKEx/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)

Question

If you have a simple question about this example contact us at VTKExProject If your question is more complex and may require extended discussion, please use the VTK Discourse Forum

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 
  vtkvtkCommonColor
  vtkvtkCommonCore
  vtkvtkCommonDataModel
  vtkvtkFiltersSources
  vtkvtkInteractionStyle
  vtkvtkRenderingContextOpenGL2
  vtkvtkRenderingCore
  vtkvtkRenderingFreeType
  vtkvtkRenderingGL2PSOpenGL2
  vtkvtkRenderingOpenGL2 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.