ImageMapToColors
VTKExamples/Cxx/Images/ImageMapToColors
Code¶
ImageMapToColors.cxx
// // Displays a "grayscale" image as a full color image via the // vtkImageMapToColors filter, which uses a lookup table to // map scalar values to colors // #include <vtkImageActor.h> #include <vtkImageData.h> #include <vtkImageMapper3D.h> #include <vtkImageMapToColors.h> #include <vtkImageProperty.h> #include <vtkInteractorStyleImage.h> #include <vtkLookupTable.h> #include <vtkRenderer.h> #include <vtkRenderWindow.h> #include <vtkRenderWindowInteractor.h> #include <vtkSmartPointer.h> #include <vtkVersion.h> int main(int, char*[]) { // Create a "grayscale" 16x16 image, 1-component pixels of type "double" vtkSmartPointer<vtkImageData> image = vtkSmartPointer<vtkImageData>::New(); int imageExtent[6] = { 0, 15, 0, 15, 0, 0 }; image->SetExtent(imageExtent); #if VTK_MAJOR_VERSION <= 5 image->SetNumberOfScalarComponents(1); image->SetScalarTypeToDouble(); #else image->AllocateScalars(VTK_DOUBLE, 1); #endif double scalarvalue = 0.0; for (int y = imageExtent[2]; y <= imageExtent[3]; y++) { for (int x = imageExtent[0]; x <= imageExtent[1]; x++) { double* pixel = static_cast<double*>(image->GetScalarPointer(x, y, 0)); pixel[0] = scalarvalue; scalarvalue += 1.0; } } // Map the scalar values in the image to colors with a lookup table: vtkSmartPointer<vtkLookupTable> lookupTable = vtkSmartPointer<vtkLookupTable>::New(); lookupTable->SetNumberOfTableValues(256); lookupTable->SetRange(0.0, 255.0); lookupTable->Build(); // Pass the original image and the lookup table to a filter to create // a color image: vtkSmartPointer<vtkImageMapToColors> scalarValuesToColors = vtkSmartPointer<vtkImageMapToColors>::New(); scalarValuesToColors->SetLookupTable(lookupTable); scalarValuesToColors->PassAlphaToOutputOn(); #if VTK_MAJOR_VERSION <= 5 scalarValuesToColors->SetInput(image); #else scalarValuesToColors->SetInputData(image); #endif // Create an image actor vtkSmartPointer<vtkImageActor> imageActor = vtkSmartPointer<vtkImageActor>::New(); imageActor->GetMapper()->SetInputConnection( scalarValuesToColors->GetOutputPort()); imageActor->GetProperty()->SetInterpolationTypeToNearest(); // Visualize vtkSmartPointer<vtkRenderer> renderer = vtkSmartPointer<vtkRenderer>::New(); renderer->AddActor(imageActor); renderer->ResetCamera(); vtkSmartPointer<vtkRenderWindow> renderWindow = vtkSmartPointer<vtkRenderWindow>::New(); renderWindow->AddRenderer(renderer); vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor = vtkSmartPointer<vtkRenderWindowInteractor>::New(); vtkSmartPointer<vtkInteractorStyleImage> style = vtkSmartPointer<vtkInteractorStyleImage>::New(); renderWindowInteractor->SetInteractorStyle(style); renderWindowInteractor->SetRenderWindow(renderWindow); renderWindowInteractor->Initialize(); renderWindowInteractor->Start(); return EXIT_SUCCESS; }
CMakeLists.txt¶
cmake_minimum_required(VERSION 2.8) PROJECT(ImageMapToColors) find_package(VTK REQUIRED) include(${VTK_USE_FILE}) add_executable(ImageMapToColors MACOSX_BUNDLE ImageMapToColors.cxx) target_link_libraries(ImageMapToColors ${VTK_LIBRARIES})
Download and Build ImageMapToColors¶
Danger
The generation of tar files has not been ported to the new VTKExamples. Some tarballs may be missing or out-of-date.
Click here to download ImageMapToColors and its CMakeLists.txt file. Once the tarball ImageMapToColors.tar has been downloaded and extracted,
cd ImageMapToColors/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:
./ImageMapToColors
WINDOWS USERS PLEASE NOTE: Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.