ExtractSelection
VTKExamples/Cxx/PolyData/ExtractSelection
Description
This example creates 50 random points and extracts 10 of them (the points with ids 10-19).
Code
ExtractSelection.cxx
#include <vtkVersion.h>
#include <vtkSmartPointer.h>
#include <vtkInformation.h>
#include <vtkPointSource.h>
#include <vtkExtractSelection.h>
#include <vtkSelection.h>
#include <vtkSelectionNode.h>
#include <vtkPolyData.h>
#include <vtkUnstructuredGrid.h>
#include <vtkIdTypeArray.h>
#include <vtkDataSetMapper.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSphereSource.h>
#include <vtkVertexGlyphFilter.h>
int main(int, char *[])
{
vtkSmartPointer<vtkPointSource> pointSource =
vtkSmartPointer<vtkPointSource>::New();
pointSource->SetNumberOfPoints(50);
pointSource->Update();
std::cout << "There are " << pointSource->GetOutput()->GetNumberOfPoints()
<< " input points." << std::endl;
vtkSmartPointer<vtkIdTypeArray> ids =
vtkSmartPointer<vtkIdTypeArray>::New();
ids->SetNumberOfComponents(1);
// Set values
for(unsigned int i = 10; i < 20; i++)
{
ids->InsertNextValue(i);
}
vtkSmartPointer<vtkSelectionNode> selectionNode =
vtkSmartPointer<vtkSelectionNode>::New();
selectionNode->SetFieldType(vtkSelectionNode::POINT);
selectionNode->SetContentType(vtkSelectionNode::INDICES);
selectionNode->SetSelectionList(ids);
vtkSmartPointer<vtkSelection> selection =
vtkSmartPointer<vtkSelection>::New();
selection->AddNode(selectionNode);
vtkSmartPointer<vtkExtractSelection> extractSelection =
vtkSmartPointer<vtkExtractSelection>::New();
extractSelection->SetInputConnection(0, pointSource->GetOutputPort());
#if VTK_MAJOR_VERSION <= 5
extractSelection->SetInput(1, selection);
#else
extractSelection->SetInputData(1, selection);
#endif
extractSelection->Update();
// In selection
vtkSmartPointer<vtkUnstructuredGrid> selected =
vtkSmartPointer<vtkUnstructuredGrid>::New();
selected->ShallowCopy(extractSelection->GetOutput());
std::cout << "There are " << selected->GetNumberOfPoints()
<< " points in the selection." << std::endl;
std::cout << "There are " << selected->GetNumberOfCells()
<< " cells in the selection." << std::endl;
// Get points that are NOT in the selection
selectionNode->GetProperties()->Set(vtkSelectionNode::INVERSE(), 1); //invert the selection
extractSelection->Update();
vtkSmartPointer<vtkUnstructuredGrid> notSelected =
vtkSmartPointer<vtkUnstructuredGrid>::New();
notSelected->ShallowCopy(extractSelection->GetOutput());
std::cout << "There are " << notSelected->GetNumberOfPoints()
<< " points NOT in the selection." << std::endl;
std::cout << "There are " << notSelected->GetNumberOfCells()
<< " cells NOT in the selection." << std::endl;
vtkSmartPointer<vtkDataSetMapper> inputMapper =
vtkSmartPointer<vtkDataSetMapper>::New();
inputMapper->SetInputConnection(pointSource->GetOutputPort());
vtkSmartPointer<vtkActor> inputActor =
vtkSmartPointer<vtkActor>::New();
inputActor->SetMapper(inputMapper);
vtkSmartPointer<vtkDataSetMapper> selectedMapper =
vtkSmartPointer<vtkDataSetMapper>::New();
#if VTK_MAJOR_VERSION <= 5
selectedMapper->SetInputConnection(selected->GetProducerPort());
#else
selectedMapper->SetInputData(selected);
#endif
vtkSmartPointer<vtkActor> selectedActor =
vtkSmartPointer<vtkActor>::New();
selectedActor->SetMapper(selectedMapper);
vtkSmartPointer<vtkDataSetMapper> notSelectedMapper =
vtkSmartPointer<vtkDataSetMapper>::New();
#if VTK_MAJOR_VERSION <= 5
notSelectedMapper->SetInputConnection(notSelected->GetProducerPort());
#else
notSelectedMapper->SetInputData(notSelected);
#endif
vtkSmartPointer<vtkActor> notSelectedActor =
vtkSmartPointer<vtkActor>::New();
notSelectedActor->SetMapper(notSelectedMapper);
// There will be one render window
vtkSmartPointer<vtkRenderWindow> renderWindow =
vtkSmartPointer<vtkRenderWindow>::New();
renderWindow->SetSize(900, 300);
// And one interactor
vtkSmartPointer<vtkRenderWindowInteractor> interactor =
vtkSmartPointer<vtkRenderWindowInteractor>::New();
interactor->SetRenderWindow(renderWindow);
// Define viewport ranges
// (xmin, ymin, xmax, ymax)
double leftViewport[4] = {0.0, 0.0, 0.33, 1.0};
double centerViewport[4] = {0.33, 0.0, .66, 1.0};
double rightViewport[4] = {0.66, 0.0, 1.0, 1.0};
// Setup the renderers
vtkSmartPointer<vtkRenderer> leftRenderer =
vtkSmartPointer<vtkRenderer>::New();
renderWindow->AddRenderer(leftRenderer);
leftRenderer->SetViewport(leftViewport);
leftRenderer->SetBackground(.6, .5, .4);
vtkSmartPointer<vtkRenderer> centerRenderer =
vtkSmartPointer<vtkRenderer>::New();
renderWindow->AddRenderer(centerRenderer);
centerRenderer->SetViewport(centerViewport);
centerRenderer->SetBackground(.3, .1, .4);
vtkSmartPointer<vtkRenderer> rightRenderer =
vtkSmartPointer<vtkRenderer>::New();
renderWindow->AddRenderer(rightRenderer);
rightRenderer->SetViewport(rightViewport);
rightRenderer->SetBackground(.4, .5, .6);
leftRenderer->AddActor(inputActor);
centerRenderer->AddActor(selectedActor);
rightRenderer->AddActor(notSelectedActor);
leftRenderer->ResetCamera();
centerRenderer->ResetCamera();
rightRenderer->ResetCamera();
renderWindow->Render();
interactor->Start();
return EXIT_SUCCESS;
}
CMakeLists.txt
cmake_minimum_required(VERSION 2.8)
PROJECT(ExtractSelection)
find_package(VTK REQUIRED)
include(${VTK_USE_FILE})
add_executable(ExtractSelection MACOSX_BUNDLE ExtractSelection.cxx)
target_link_libraries(ExtractSelection ${VTK_LIBRARIES})
Download and Build ExtractSelection
Click here to download ExtractSelection and its CMakeLists.txt file. Once the tarball ExtractSelection.tar has been downloaded and extracted,
cd ExtractSelection/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:
./ExtractSelection
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.