ColorMapToLUT
Repository source: ColorMapToLUT
Description¶
Demonstrate a cone using the vtkDiscretizableColorTransferFunction to generate the colormap.
These two Python functions can be used to generate C++ and Python functions from a JSON or XML colormap. They can then be copied into ColorMapToLUT.cxx, ColorMapToLUT.py or into your own code.
Feel free to use either of these programs to generate different colormaps until you find one you like.
A good initial source for color maps is: SciVisColor -- this will provide you with plenty of XML examples.
ColorMapToLUT_JSON will allow you to select colormaps by name from ParaView Default Colormaps.
Other languages
See (Python), (PythonicAPI)
Question
If you have a question about this example, please use the VTK Discourse Forum
Code¶
ColorMapToLUT.cxx
#include <vtkActor.h>
#include <vtkConeSource.h>
#include <vtkDiscretizableColorTransferFunction.h>
#include <vtkElevationFilter.h>
#include <vtkInteractorStyleTrackballCamera.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkPolyDataMapper.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
// #include <vtkSphereSource.h>
#include <array>
namespace {
vtkNew<vtkDiscretizableColorTransferFunction> GetCTF();
}
int main(int, char*[])
{
std::array<unsigned char, 4> bkg{82, 87, 110, 255};
vtkNew<vtkNamedColors> colors;
colors->SetColor("ParaViewBkg", bkg.data());
vtkNew<vtkRenderer> ren;
ren->SetBackground(colors->GetColor3d("ParaViewBkg").GetData());
vtkNew<vtkRenderWindow> renWin;
renWin->SetSize(640, 480);
renWin->SetWindowName("ColorMapToLUT");
renWin->AddRenderer(ren);
vtkNew<vtkRenderWindowInteractor> iRen;
iRen->SetRenderWindow(renWin);
vtkNew<vtkInteractorStyleTrackballCamera> style;
iRen->SetInteractorStyle(style);
// vtkNew<vtkSphereSource> sphere;
// sphere->SetThetaResolution(64);
// sphere->SetPhiResolution(32);
// auto bounds = sphere->GetOutput()->GetBounds();
vtkNew<vtkConeSource> cone;
cone->SetResolution(6);
cone->SetDirection(0, 1, 0);
cone->SetHeight(1);
cone->Update();
auto bounds = cone->GetOutput()->GetBounds();
vtkNew<vtkElevationFilter> elevation_filter;
elevation_filter->SetLowPoint(0, bounds[2], 0);
elevation_filter->SetHighPoint(0, bounds[3], 0);
elevation_filter->SetInputConnection(cone->GetOutputPort());
// elevation_filter->SetInputConnection(sphere->GetOutputPort());
auto ctf = GetCTF();
vtkNew<vtkPolyDataMapper> mapper;
mapper->SetInputConnection(elevation_filter->GetOutputPort());
mapper->SetLookupTable(ctf);
mapper->SetColorModeToMapScalars();
mapper->InterpolateScalarsBeforeMappingOn();
vtkNew<vtkActor> actor;
actor->SetMapper(mapper);
ren->AddActor(actor);
renWin->Render();
iRen->Start();
return EXIT_SUCCESS;
}
namespace {
vtkNew<vtkDiscretizableColorTransferFunction> GetCTF()
{
// name: Fast, creator: Francesca Samsel and Alan W. Scott
// interpolationspace: lab, interpolationtype: linear, space: RGB
// file name: Fast.xml
vtkNew<vtkDiscretizableColorTransferFunction> ctf;
ctf->SetColorSpaceToLab();
ctf->SetScaleToLinear();
ctf->SetNanColor(0, 0, 0);
ctf->SetAboveRangeColor(0, 0, 0);
ctf->UseAboveRangeColorOn();
ctf->SetBelowRangeColor(0, 0, 0);
ctf->UseBelowRangeColorOn();
ctf->AddRGBPoint(0, 0.05639999999999999, 0.05639999999999999, 0.47);
ctf->AddRGBPoint(0.17159223942480895, 0.24300000000000013, 0.4603500000000004,
0.81);
ctf->AddRGBPoint(0.2984914818394138, 0.3568143826543521, 0.7450246485363142,
0.954367702893722);
ctf->AddRGBPoint(0.4321287371255907, 0.6882, 0.93, 0.9179099999999999);
ctf->AddRGBPoint(0.5, 0.8994959551205902, 0.944646394975174,
0.7686567142818399);
ctf->AddRGBPoint(0.5882260353170073, 0.957107977357604, 0.8338185108985666,
0.5089156299842102);
ctf->AddRGBPoint(0.7061412605695164, 0.9275207599610714, 0.6214389091739178,
0.31535705838676426);
ctf->AddRGBPoint(0.8476395308725272, 0.8, 0.3520000000000001,
0.15999999999999998);
ctf->AddRGBPoint(1, 0.59, 0.07670000000000013, 0.11947499999999994);
ctf->SetNumberOfValues(9);
ctf->DiscretizeOff();
return ctf;
}
} // namespace
CMakeLists.txt¶
cmake_minimum_required(VERSION 3.12 FATAL_ERROR)
project(ColorMapToLUT)
find_package(VTK COMPONENTS
CommonColor
CommonCore
FiltersCore
FiltersSources
InteractionStyle
RenderingContextOpenGL2
RenderingCore
RenderingFreeType
RenderingGL2PSOpenGL2
RenderingOpenGL2
)
if (NOT VTK_FOUND)
message(FATAL_ERROR "ColorMapToLUT: 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(ColorMapToLUT MACOSX_BUNDLE ColorMapToLUT.cxx )
target_link_libraries(ColorMapToLUT PRIVATE ${VTK_LIBRARIES}
)
# vtk_module_autoinit is needed
vtk_module_autoinit(
TARGETS ColorMapToLUT
MODULES ${VTK_LIBRARIES}
)
Download and Build ColorMapToLUT¶
Click here to download ColorMapToLUT and its CMakeLists.txt file. Once the tarball ColorMapToLUT.tar has been downloaded and extracted,
cd ColorMapToLUT/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:
./ColorMapToLUT
WINDOWS USERS
Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.