Comment visualiser les attributs de cellule sous forme d'étiquettes

Question

Résolu:cxx Le fichier ci-dessous fonctionne comme prévu maintenant. Merci à @tomj car j'ai aussi utilisé ses idées.

J'ai un fichier de données (.vtk) à partir duquel je lis une grille non structurée. Comment puis-je afficher les attributs de cellule en tant qu'étiquettes?

cxx:

#include <vtkLookupTable.h> 
#include <vtkCellData.h> 
#include <vtkSmartPointer.h> 
#include <vtkActor2D.h> 
#include <vtkProperty.h> 
#include <vtkDataSetMapper.h> 
#include <vtkLabeledDataMapper.h> 
#include <vtkUnstructuredGridReader.h> 
#include <vtkUnstructuredGrid.h> 
#include <vtkUnstructuredGridGeometryFilter.h> 
#include <vtkRenderWindow.h> 
#include <vtkRenderWindowInteractor.h> 
#include <vtkRenderer.h> 
#include "vtkIdFilter.h" 
#include "vtkCellCenters.h" 
#include <iostream> 

int main(int argc, char* argv[]) 
{ 
    std::string inputFilename = argv[1]; 

    // read file. 
    vtkSmartPointer<vtkUnstructuredGridReader> reader = vtkSmartPointer<vtkUnstructuredGridReader>::New(); 
    reader->SetFileName(inputFilename.c_str()); 
    reader->ReadAllScalarsOn(); 
    reader->SetScalarsName(reader->GetScalarsNameInFile(0)); 
    reader->Update(); 

    unsigned int ncell = reader->GetOutput()->GetNumberOfCells(); 

    // get attributes. 
    vtkSmartPointer<vtkUnstructuredGrid> ugrid = reader->GetOutput(); 
    vtkSmartPointer<vtkCellData> cellData = ugrid->GetCellData(); 
    vtkSmartPointer<vtkDataArray> data = cellData->GetScalars(reader->GetScalarsNameInFile(0)); 

    // validate that attributes are read correctly. 
    for (int i=0; i<ncell; i++) 
    { 
     std::cout<< i << ": " << data->GetComponent(i,0)<< std::endl; 
    } 
    data = cellData->GetScalars(reader->GetScalarsNameInFile(1)); 
    for (int i=0; i<ncell; i++) 
    { 
     std::cout<< i << ": " << data->GetComponent(i,0)<< std::endl; 
    } 

    data = cellData->GetScalars(reader->GetScalarsNameInFile(0)); 

    // geometry filter. 
    vtkSmartPointer<vtkUnstructuredGridGeometryFilter> geometryFilter = vtkSmartPointer<vtkUnstructuredGridGeometryFilter>::New(); 
    geometryFilter->SetInputConnection(reader->GetOutputPort()); 
    geometryFilter->Update(); 

    // Generate data arrays containing point and cell ids 
    vtkSmartPointer<vtkIdFilter> ids = vtkSmartPointer<vtkIdFilter>::New(); 
    ids->SetInputConnection(geometryFilter->GetOutputPort()); 
    ids->PointIdsOff(); 
    ids->CellIdsOff(); 
    ids->FieldDataOn(); 

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

    // lut 
    vtkSmartPointer<vtkLookupTable> lut = vtkSmartPointer<vtkLookupTable>::New(); 
    lut->SetNumberOfTableValues(ncell); 
    lut->Build(); 
    lut->SetTableValue(0, 1, 0, 0, 1); // red. 
    lut->SetTableValue(1, 0, 1, 0, 1); // green. 
    lut->SetTableValue(2, 0, 0, 1, 1); // blue. 

    // mapper. 
    vtkSmartPointer<vtkDataSetMapper> mapper = vtkSmartPointer<vtkDataSetMapper>::New(); 
    mapper->SetInputConnection(geometryFilter->GetOutputPort()); 
    mapper->SetLookupTable(lut); 
    mapper->SetScalarVisibility(1); 
    mapper->SetScalarModeToUseCellData(); 
    mapper->SetScalarRange(11, 13); 
    mapper->GetInput()->GetCellData()->SetActiveScalars("cell_tag"); 

    // label mapper. 
    vtkSmartPointer<vtkLabeledDataMapper> label_mapper = vtkSmartPointer<vtkLabeledDataMapper>::New(); 
    label_mapper->SetInputConnection(cc->GetOutputPort()); 
    label_mapper->SetLabelModeToLabelScalars(); 

    // actor. 
    vtkSmartPointer<vtkActor> actor = vtkSmartPointer<vtkActor>::New(); 
    actor->SetMapper(mapper); 
    actor->GetProperty()->SetRepresentationToWireframe(); 

    // label actor. 
    vtkSmartPointer<vtkActor2D> label_actor = vtkSmartPointer<vtkActor2D>::New(); 
    label_actor->SetMapper(label_mapper); 

    // renderer. 
    vtkSmartPointer<vtkRenderer> renderer = vtkSmartPointer<vtkRenderer>::New(); 
    vtkSmartPointer<vtkRenderWindow> renderWindow = vtkSmartPointer<vtkRenderWindow>::New(); 
    renderWindow->AddRenderer(renderer); 
    vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor = vtkSmartPointer<vtkRenderWindowInteractor>::New(); 
    renderWindowInteractor->SetRenderWindow(renderWindow); 
    renderer->AddActor(actor); 
    renderer->AddActor(label_actor); 
    renderWindow->Render(); 
    renderWindowInteractor->Start(); 

    return EXIT_SUCCESS; 
} 

fichier de données (.vtk):

# vtk DataFile Version 3.0 
All in VTK format 
ASCII 
DATASET UNSTRUCTURED_GRID 
POINTS 8 float 
-20 0 0 
-12.898 0 0 
-7.65367 18.4776 0 
-14.1421 14.1421 0 
-18.4776 7.65367 0 
-11.8832 4.95205 0 
-9.03623 9.14123 0 
-4.79931 11.937 0 

CELLS 3 15 
4 0 1 5 4 
4 4 5 6 3 
4 3 6 7 2 
CELL_TYPES 3 
9 
9 
9 
CELL_DATA 3 
SCALARS oga_cell_type int 1 
LOOKUP_TABLE default 
5 
6 
7 
SCALARS cell_tag int 1 
LOOKUP_TABLE default 
11 
12 
13 

sortie:

Answer 1

See for example this tutorial, mais il se résume assez bien à ceci:

mapper->SetLookupTable(lut); // lut is a lookup table for colors, see the linked tutorial or other vtk tutorials about look up tables 
mapper->SetScalarVisibility(1); 
mapper->SetScalarModeToUseCellData(); 
mapper->GetInput()->GetCellData()->SetActiveScalars("nameOfTheArrayToUseForColoringTheCells");