CombiningRGBChannels
VTKExamples/Cxx/Images/CombiningRGBChannels
Description¶
This example creates three images of a square. Each square slightly overlaps the previous square. These three layers are then interpreted as the R, G, and B channel of an RGB image, by the use of vtkImageAppendComponents.
Note
You MUST add 3 inputs or no output will be produced.
Seealso
For the reverse operation, see ExtractComponents.
Code¶
CombiningRGBChannels.cxx
#include <vtkSmartPointer.h> #include <vtkImageData.h> #include <vtkImageMapper3D.h> #include <vtkImageAppendComponents.h> #include <vtkImageCanvasSource2D.h> #include <vtkRenderWindow.h> #include <vtkRenderWindowInteractor.h> #include <vtkInteractorStyleImage.h> #include <vtkRenderer.h> #include <vtkJPEGReader.h> #include <vtkImageActor.h> int main(int, char *[]) { // Create an image (will be used as the R channel) vtkSmartPointer<vtkImageCanvasSource2D> red = vtkSmartPointer<vtkImageCanvasSource2D>::New(); red->SetScalarTypeToUnsignedChar(); red->SetNumberOfScalarComponents(1); red->SetExtent(0, 100, 0, 100, 0, 0); red->SetDrawColor(0, 0, 0, 0); red->FillBox(0,100,0,100); red->SetDrawColor(255, 0, 0, 0); red->FillBox(20,40,20,40); red->Update(); // Create an image (will be used as the G channel) vtkSmartPointer<vtkImageCanvasSource2D> green = vtkSmartPointer<vtkImageCanvasSource2D>::New(); green->SetScalarTypeToUnsignedChar(); green->SetNumberOfScalarComponents(1); green->SetExtent(0, 100, 0, 100, 0, 0); green->SetDrawColor(0, 0, 0, 0); green->FillBox(0,100,0,100); green->SetDrawColor(255, 0, 0, 0); green->FillBox(30,50,30,50); green->Update(); // Create an image (will be used as the B channel) vtkSmartPointer<vtkImageCanvasSource2D> blue = vtkSmartPointer<vtkImageCanvasSource2D>::New(); blue->SetScalarTypeToUnsignedChar(); blue->SetNumberOfScalarComponents(1); blue->SetExtent(0, 100, 0, 100, 0, 0); blue->SetDrawColor(0, 0, 0, 0); blue->FillBox(0,100,0,100); blue->SetDrawColor(255, 0, 0, 0); blue->FillBox(40,60,40,60); blue->Update(); vtkSmartPointer<vtkImageAppendComponents> appendFilter = vtkSmartPointer<vtkImageAppendComponents>::New(); appendFilter->SetInputConnection(0, red->GetOutputPort()); appendFilter->AddInputConnection(0, green->GetOutputPort()); appendFilter->AddInputConnection(0, blue->GetOutputPort()); appendFilter->Update(); // Create actors vtkSmartPointer<vtkImageActor> redActor = vtkSmartPointer<vtkImageActor>::New(); redActor->GetMapper()->SetInputConnection(red->GetOutputPort()); vtkSmartPointer<vtkImageActor> greenActor = vtkSmartPointer<vtkImageActor>::New(); greenActor->GetMapper()->SetInputConnection(green->GetOutputPort()); vtkSmartPointer<vtkImageActor> blueActor = vtkSmartPointer<vtkImageActor>::New(); blueActor->GetMapper()->SetInputConnection(blue->GetOutputPort()); vtkSmartPointer<vtkImageActor> combinedActor = vtkSmartPointer<vtkImageActor>::New(); combinedActor->GetMapper()->SetInputConnection(appendFilter->GetOutputPort()); // Define viewport ranges // (xmin, ymin, xmax, ymax) double redViewport[4] = {0.0, 0.0, 0.25, 1.0}; double greenViewport[4] = {0.25, 0.0, 0.5, 1.0}; double blueViewport[4] = {0.5, 0.0, 0.75, 1.0}; double combinedViewport[4] = {0.75, 0.0, 1.0, 1.0}; // Setup renderers vtkSmartPointer<vtkRenderer> redRenderer = vtkSmartPointer<vtkRenderer>::New(); redRenderer->SetViewport(redViewport); redRenderer->AddActor(redActor); redRenderer->ResetCamera(); redRenderer->SetBackground(.4, .5, .6); vtkSmartPointer<vtkRenderer> greenRenderer = vtkSmartPointer<vtkRenderer>::New(); greenRenderer->SetViewport(greenViewport); greenRenderer->AddActor(greenActor); greenRenderer->ResetCamera(); greenRenderer->SetBackground(.4, .5, .7); vtkSmartPointer<vtkRenderer> blueRenderer = vtkSmartPointer<vtkRenderer>::New(); blueRenderer->SetViewport(blueViewport); blueRenderer->AddActor(blueActor); blueRenderer->ResetCamera(); blueRenderer->SetBackground(.4, .5, .8); vtkSmartPointer<vtkRenderer> combinedRenderer = vtkSmartPointer<vtkRenderer>::New(); combinedRenderer->SetViewport(combinedViewport); combinedRenderer->AddActor(combinedActor); combinedRenderer->ResetCamera(); combinedRenderer->SetBackground(.4, .5, .9); // Setup render window vtkSmartPointer<vtkRenderWindow> renderWindow = vtkSmartPointer<vtkRenderWindow>::New(); renderWindow->SetSize(1000, 250); renderWindow->AddRenderer(redRenderer); renderWindow->AddRenderer(greenRenderer); renderWindow->AddRenderer(blueRenderer); renderWindow->AddRenderer(combinedRenderer); // Setup render window interactor vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor = vtkSmartPointer<vtkRenderWindowInteractor>::New(); vtkSmartPointer<vtkInteractorStyleImage> style = vtkSmartPointer<vtkInteractorStyleImage>::New(); renderWindowInteractor->SetInteractorStyle(style); // Render and start interaction renderWindowInteractor->SetRenderWindow(renderWindow); renderWindowInteractor->Initialize(); renderWindowInteractor->Start(); return EXIT_SUCCESS; }
CMakeLists.txt¶
cmake_minimum_required(VERSION 2.8) PROJECT(CombiningRGBChannels) find_package(VTK REQUIRED) include(${VTK_USE_FILE}) add_executable(CombiningRGBChannels MACOSX_BUNDLE CombiningRGBChannels.cxx) target_link_libraries(CombiningRGBChannels ${VTK_LIBRARIES})
Download and Build CombiningRGBChannels¶
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 CombiningRGBChannels and its CMakeLists.txt file. Once the tarball CombiningRGBChannels.tar has been downloaded and extracted,
cd CombiningRGBChannels/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:
./CombiningRGBChannels
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.