VTK/Examples/Cxx/Visualization/LabelMesh

This example was translated into C++ from its TCL counterpart by Jake Nickel from the University of Iowa. It demonstrates the use of vtkLabeledDataMapper. This class is used for displaying numerical data from an underlying data set. In the case of this example, the underlying data are the point and cell ids.

LabeledMesh.cxx

#include "vtkSmartPointer.h"
#include "vtkVersion.h"

#include "vtkPoints.h"
#include "vtkCellArray.h"
#include "vtkPolyData.h"
#include "vtkPolyDataMapper2D.h"
#include "vtkActor2D.h"
#include "vtkSphereSource.h"
#include "vtkPolyDataMapper.h"
#include "vtkActor.h"
#include "vtkIdFilter.h"
#include "vtkRenderer.h"
#include "vtkSelectVisiblePoints.h"
#include "vtkLabeledDataMapper.h"
#include "vtkCellCenters.h"
#include "vtkLabeledDataMapper.h"
#include "vtkRenderWindow.h"
#include "vtkRenderWindowInteractor.h"
#include "vtkTextProperty.h"

static int xLength;
static int yLength;
static vtkSmartPointer<vtkSelectVisiblePoints> visPts;
static vtkSmartPointer<vtkSelectVisiblePoints> visCells;
static vtkSmartPointer<vtkPoints> pts;
static vtkSmartPointer<vtkRenderWindow> renWin;

// Create a procedure to draw the selection window at each location it
// is moved to.
static void PlaceWindow( int xmin, int ymin )
{
  int xmax = xmin + xLength;
  int ymax = ymin + yLength;

  visPts->SetSelection( xmin, xmax, ymin, ymax );
  visCells->SetSelection( xmin, xmax, ymin, ymax );

  pts->InsertPoint( 0, xmin, ymin, 0 );
  pts->InsertPoint( 1, xmin, ymin, 0 );
  pts->InsertPoint( 2, xmin, ymin, 0 );
  pts->InsertPoint( 3, xmin, ymin, 0 );

  // Call Modified because InsertPoints does not modify vtkPoints
  // (for performance reasons).
  pts->Modified();

  renWin->Render();
}

// Create a procedure to move the selection window across the data set.
static void MoveWindow()
{
  for( int y = 100; y < 300; y += 25 )
  {
    for( int x = 100; x < 300; x += 25 )
    {
      PlaceWindow( x, y );
    }
  }
}

int main(int argc, char *argv[] )
{
  // Create a selection window.  We will display the point and cell ids that
  // lie within this window.
  int xmin = 200;
  xLength = 100;
  int xmax = xmin + xLength;
  int ymin = 200;
  yLength = 100;
  int ymax = ymin + yLength;

  pts = vtkSmartPointer<vtkPoints>::New();
  pts->InsertPoint( 0, xmin, ymin, 0 );
  pts->InsertPoint( 1, xmax, ymin, 0 );
  pts->InsertPoint( 2, xmax, ymax, 0 );
  pts->InsertPoint( 3, xmin, ymax, 0 );

  vtkSmartPointer<vtkCellArray> rect =
    vtkSmartPointer<vtkCellArray>::New();
  rect->InsertNextCell( 5 );
  rect->InsertCellPoint( 0 );
  rect->InsertCellPoint( 1 );
  rect->InsertCellPoint( 2 );
  rect->InsertCellPoint( 3 );
  rect->InsertCellPoint( 0 );

  vtkSmartPointer<vtkPolyData> selectRect =
    vtkSmartPointer<vtkPolyData>::New();
  selectRect->SetPoints( pts );
  selectRect->SetLines( rect );

  vtkSmartPointer<vtkPolyDataMapper2D> rectMapper =
    vtkSmartPointer<vtkPolyDataMapper2D>::New();
#if VTK_MAJOR_VERSION <= 5
  rectMapper->SetInput( selectRect );
#else
  rectMapper->SetInputData( selectRect );
#endif

  vtkSmartPointer<vtkActor2D> rectActor =
    vtkSmartPointer<vtkActor2D>::New();
  rectActor->SetMapper( rectMapper );

  // Create a sphere and its associated mapper and actor.
  vtkSmartPointer<vtkSphereSource> sphere =
    vtkSmartPointer<vtkSphereSource>::New();
  vtkSmartPointer<vtkPolyDataMapper> sphereMapper =
    vtkSmartPointer<vtkPolyDataMapper>::New();
  sphereMapper->SetInputConnection(sphere->GetOutputPort());
  sphereMapper->GlobalImmediateModeRenderingOn();

  vtkSmartPointer<vtkActor> sphereActor =
    vtkSmartPointer<vtkActor>::New();
  sphereActor->SetMapper( sphereMapper );

  // Generate data arrays containing point and cell ids
  vtkSmartPointer<vtkIdFilter> ids =
    vtkSmartPointer<vtkIdFilter>::New();
  ids->SetInputConnection( sphere->GetOutputPort() );
  ids->PointIdsOn();
  ids->CellIdsOn();
  ids->FieldDataOn();

  // Create the renderer here because vtkSelectVisiblePoints needs it.
  vtkSmartPointer<vtkRenderer> ren1 =
    vtkSmartPointer<vtkRenderer>::New();

  // Create labels for points
  visPts = vtkSmartPointer<vtkSelectVisiblePoints>::New();
  visPts->SetInputConnection( ids->GetOutputPort() );
  visPts->SetRenderer( ren1 );
  visPts->SelectionWindowOn();
  visPts->SetSelection( xmin, xmin + xLength, ymin, ymin + yLength );

  // Create the mapper to display the point ids.  Specify the
  // format to use for the labels.  Also create the associated actor.
  vtkSmartPointer<vtkLabeledDataMapper> ldm =
    vtkSmartPointer<vtkLabeledDataMapper>::New();
  ldm->SetInputConnection( visPts->GetOutputPort() );
  ldm->SetLabelModeToLabelFieldData();

  vtkSmartPointer<vtkActor2D> pointLabels =
    vtkSmartPointer<vtkActor2D>::New();
  pointLabels->SetMapper( ldm );

  // Create labels for cells
  vtkSmartPointer<vtkCellCenters> cc =
    vtkSmartPointer<vtkCellCenters>::New();
  cc->SetInputConnection( ids->GetOutputPort() );

  visCells = vtkSmartPointer<vtkSelectVisiblePoints>::New();
  visCells->SetInputConnection( cc->GetOutputPort() );
  visCells->SetRenderer( ren1 );
  visCells->SelectionWindowOn();
  visCells->SetSelection( xmin, xmin + xLength, ymin, ymin + yLength );

  // Create the mapper to display the cell ids.  Specify the
  // format to use for the labels.  Also create the associated actor.
  vtkSmartPointer<vtkLabeledDataMapper> cellMapper =
    vtkSmartPointer<vtkLabeledDataMapper>::New();
  cellMapper->SetInputConnection( visCells->GetOutputPort() );
  cellMapper->SetLabelModeToLabelFieldData();
  cellMapper->GetLabelTextProperty()->SetColor( 0, 1, 0 );

  vtkSmartPointer<vtkActor2D> cellLabels =
    vtkSmartPointer<vtkActor2D>::New();
  cellLabels->SetMapper( cellMapper );

  // Create the RenderWindow and RenderWindowInteractor
  renWin = vtkSmartPointer<vtkRenderWindow>::New();
  renWin->AddRenderer( ren1 );

  vtkSmartPointer<vtkRenderWindowInteractor> iren =
    vtkSmartPointer<vtkRenderWindowInteractor>::New();
  iren->SetRenderWindow( renWin );

  // Add the actors to the renderer; set the background and size; render
  ren1->AddActor( sphereActor );
  ren1->AddActor2D( rectActor );
  ren1->AddActor2D( pointLabels );
  ren1->AddActor2D( cellLabels );

  ren1->SetBackground( 1, 1, 1 );
  renWin->SetSize( 500, 500 );
  renWin->Render();

  // Move the selection window across the data set.
  MoveWindow();

  // Put the selection window in the center of the render window.
  // This works because the xmin = ymin = 200, xLength = yLength = 100, and
  // the render window size is 500 x 500.
  PlaceWindow( xmin, ymin );

  iren->Initialize();
  iren->Start();

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 2.8)

project(LabeledMesh)

find_package(VTK REQUIRED)
include(${VTK_USE_FILE})

add_executable(LabeledMesh LabeledMesh.cxx)

if(VTK_LIBRARIES)
  target_link_libraries(LabeledMesh ${VTK_LIBRARIES})
else()
  target_link_libraries(LabeledMesh vtkHybrid)
endif()