LabelPlacementMapper
VTKExamples/Cxx/Visualization/LabelPlacementMapper
Description
This example demonstrates how to add labels from an array to points. Each point is given a priority that determines which labels are visible when space is limited.
Code
LabelPlacementMapper.cxx
#include <vtkActor.h>
#include <vtkActor2D.h>
#include <vtkIntArray.h>
#include <vtkLabelPlacementMapper.h>
#include <vtkPointData.h>
#include <vtkPointSetToLabelHierarchy.h>
#include <vtkPointSource.h>
#include <vtkPolyDataMapper.h>
#include <vtkRenderer.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkSmartPointer.h>
#include <vtkStringArray.h>
int main(int, char *[])
{
// Create a point set.
vtkSmartPointer<vtkPointSource> pointSource =
vtkSmartPointer<vtkPointSource>::New();
pointSource->SetNumberOfPoints(6);
pointSource->Update();
// Add label array.
vtkSmartPointer<vtkStringArray> labels =
vtkSmartPointer<vtkStringArray>::New();
labels->SetNumberOfValues(6);
labels->SetName("labels");
labels->SetValue(0, "Priority 10");
labels->SetValue(1, "Priority 7");
labels->SetValue(2, "Priority 6");
labels->SetValue(3, "Priority 4");
labels->SetValue(4, "Priority 4");
labels->SetValue(5, "Priority 4");
pointSource->GetOutput()->GetPointData()->AddArray(labels);
// Add priority array.
vtkSmartPointer<vtkIntArray> sizes =
vtkSmartPointer<vtkIntArray>::New();
sizes->SetNumberOfValues(6);
sizes->SetName("sizes");
sizes->SetValue(0, 10);
sizes->SetValue(1, 7);
sizes->SetValue(2, 6);
sizes->SetValue(3, 4);
sizes->SetValue(4, 4);
sizes->SetValue(5, 4);
pointSource->GetOutput()->GetPointData()->AddArray(sizes);
// Create a mapper and actor for the points.
vtkSmartPointer<vtkPolyDataMapper> pointMapper =
vtkSmartPointer<vtkPolyDataMapper>::New();
pointMapper->SetInputConnection(pointSource->GetOutputPort());
vtkSmartPointer<vtkActor> pointActor =
vtkSmartPointer<vtkActor>::New();
pointActor->SetMapper(pointMapper);
// Generate the label hierarchy.
vtkSmartPointer<vtkPointSetToLabelHierarchy> pointSetToLabelHierarchyFilter =
vtkSmartPointer<vtkPointSetToLabelHierarchy>::New();
pointSetToLabelHierarchyFilter->SetInputConnection(
pointSource->GetOutputPort());
pointSetToLabelHierarchyFilter->SetLabelArrayName("labels");
pointSetToLabelHierarchyFilter->SetPriorityArrayName("sizes");
pointSetToLabelHierarchyFilter->Update();
// Create a mapper and actor for the labels.
vtkSmartPointer<vtkLabelPlacementMapper> labelMapper =
vtkSmartPointer<vtkLabelPlacementMapper>::New();
labelMapper->SetInputConnection(
pointSetToLabelHierarchyFilter->GetOutputPort());
vtkSmartPointer<vtkActor2D> labelActor =
vtkSmartPointer<vtkActor2D>::New();
labelActor->SetMapper(labelMapper);
// Create a renderer, render window, and interactor.
vtkSmartPointer<vtkRenderer> renderer =
vtkSmartPointer<vtkRenderer>::New();
vtkSmartPointer<vtkRenderWindow> renderWindow =
vtkSmartPointer<vtkRenderWindow>::New();
renderWindow->AddRenderer(renderer);
vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
vtkSmartPointer<vtkRenderWindowInteractor>::New();
renderWindowInteractor->SetRenderWindow(renderWindow);
// Add the actors to the scene.
renderer->AddActor(pointActor);
renderer->AddActor(labelActor);
// Render and interact.
renderWindow->Render();
renderWindowInteractor->Start();
return EXIT_SUCCESS;
}
CMakeLists.txt
cmake_minimum_required(VERSION 2.8)
PROJECT(LabelPlacementMapper)
find_package(VTK REQUIRED)
include(${VTK_USE_FILE})
add_executable(LabelPlacementMapper MACOSX_BUNDLE LabelPlacementMapper.cxx)
target_link_libraries(LabelPlacementMapper ${VTK_LIBRARIES})
Download and Build LabelPlacementMapper
Click here to download LabelPlacementMapper and its CMakeLists.txt file. Once the tarball LabelPlacementMapper.tar has been downloaded and extracted,
cd LabelPlacementMapper/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:
./LabelPlacementMapper
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.