Method Build

Rendering/Core/vtkDiscretizableColorTransferFunction.cxx:189–291

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//------------------------------------------------------------------------------
void vtkDiscretizableColorTransferFunction::Build()
{
  this->Superclass::Build();

  if (this->LookupTableUpdateTime > this->GetMTime())
  {
    // no need to rebuild anything.
    return;
  }

  this->LookupTable->SetVectorMode(this->VectorMode);
  this->LookupTable->SetVectorComponent(this->VectorComponent);
  this->LookupTable->SetIndexedLookup(this->IndexedLookup);
  this->LookupTable->SetUseBelowRangeColor(this->UseBelowRangeColor);
  this->LookupTable->SetUseAboveRangeColor(this->UseAboveRangeColor);

  double rgba[4];
  this->GetBelowRangeColor(rgba);
  rgba[3] = 1.0;
  this->LookupTable->SetBelowRangeColor(rgba);

  this->GetAboveRangeColor(rgba);
  rgba[3] = 1.0;
  this->LookupTable->SetAboveRangeColor(rgba);

  // this is essential since other the LookupTable doesn't update the
  // annotations map. That's a bug in the implementation of
  // vtkScalarsToColors::SetAnnotations(..,..);
  this->LookupTable->SetAnnotations(nullptr, nullptr);
  this->LookupTable->SetAnnotations(this->AnnotatedValues, this->Annotations);

  if (this->IndexedLookup)
  {
    if (this->GetNumberOfIndexedColors() > 0)
    {
      // Use the specified indexed-colors.
      vtkIdType count = this->GetNumberOfAnnotatedValues();
      this->LookupTable->SetNumberOfTableValues(count);
      for (size_t cc = 0;
           cc < this->Internals->IndexedColors.size() && cc < static_cast<size_t>(count); cc++)
      {
        rgba[0] = this->Internals->IndexedColors[cc].GetData()[0];
        rgba[1] = this->Internals->IndexedColors[cc].GetData()[1];
        rgba[2] = this->Internals->IndexedColors[cc].GetData()[2];
        rgba[3] = this->Internals->IndexedColors[cc].GetData()[3];
        this->LookupTable->SetTableValue(static_cast<int>(cc), rgba);
      }
    }
    else
    {
      // old logic for backwards compatibility.
      int nv = this->GetSize();
      this->LookupTable->SetNumberOfTableValues(nv);
      double nodeVal[6];
      for (int i = 0; i < nv; ++i)
      {
        this->GetNodeValue(i, nodeVal);
        nodeVal[4] = 1.;