Method UpdateCache

Charts/Core/vtkPlotBag.cxx:81–206

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//------------------------------------------------------------------------------
bool vtkPlotBag::UpdateCache()
{
  if (!this->Superclass::UpdateCache())
  {
    return false;
  }

  vtkTable* table = this->Data->GetInput();

  this->MedianPoints->Reset();
  this->Q3Points->Reset();

  if (!this->Points)
  {
    return false;
  }
  vtkDataArray* density = vtkDataArray::SafeDownCast(table->GetColumn(2));
  if (!density)
  {
    vtkDebugMacro(<< "Update event called with no input table or density column set.");
    return false;
  }

  vtkPoints2D* points = this->Points;

  vtkIdType nbPoints = density->GetNumberOfTuples();

  // Fetch and sort arrays according their density
  std::vector<DensityVal> ids;
  ids.reserve(nbPoints);
  auto range = vtk::DataArrayTupleRange(density);
  int counter = 0;
  for (typename decltype(range)::ConstTupleReferenceType tuple : range)
  {
    ids.emplace_back(tuple[0], counter);
    counter++;
  }
  std::sort(ids.begin(), ids.end());

  vtkNew<vtkPointsProjectedHull> q3Points;
  q3Points->Allocate(nbPoints);
  vtkNew<vtkPointsProjectedHull> medianPoints;
  medianPoints->Allocate(nbPoints);

  // Compute total density sum
  double densitySum = 0.0;
  for (vtkIdType i = 0; i < nbPoints; i++)
  {
    densitySum += density->GetTuple1(i);
  }

  double sum = 0.0;
  double const medianDensity = 0.5 * densitySum;
  double const q3Density = 0.99 * densitySum;
  for (vtkIdType i = 0; i < nbPoints; i++)
  {
    double x[2];
    points->GetPoint(ids[i].Id, x);