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
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.