Method CopyAllocate

Common/DataModel/vtkDataSetAttributesFieldList.cxx:563–636

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void vtkDataSetAttributesFieldList::CopyAllocate(
  vtkDataSetAttributes* output, int ctype, vtkIdType sz, vtkIdType ext) const
{
  auto& internals = *this->Internals;
  // lets remove empty items to make iteration easier.
  internals.Prune();

  sz = sz > 0 ? sz : internals.NumberOfTuples;

  // these are pointers to fields to be tagged as attributes.
  const auto attribute_ptrs = detail::GetAttributes(internals.Fields);

  for (auto& pair : internals.Fields)
  {
    const auto& name = pair.first;
    const auto& fieldInfo = pair.second;
    fieldInfo.OutputLocation = -1;

    assert(!fieldInfo.IsEmpty());

    bool skip_field = false;
    bool is_attribute = false;

    // lets determine if the field is to be copied over (rather skipped) using attribute flags
    // if the field is marked as any of the attribute types
    for (int attrType = 0; attrType < vtkDataSetAttributes::NUM_ATTRIBUTES; ++attrType)
    {
      if (attribute_ptrs[attrType] == &fieldInfo &&
        output->CopyAttributeFlags[ctype][attrType] == 0)
      {
        skip_field = true;
      }

      is_attribute = is_attribute | (attribute_ptrs[attrType] == &fieldInfo);
    }

    if (skip_field)
    {
      continue;
    }

    if (!is_attribute)
    {
      // if the field it not an attribute, check if it's to copied using array rules.
      // (this is directly copied over from vtkDataSetAttributes::FieldList,
      // the intent is a little unclear to me).
      const int flag = output->GetFlag(name.c_str());
      const bool copy = ((flag != 0) && !(output->DoCopyAllOff && (flag != 1)));
      if (!copy)
      {
        continue;
      }
    }

    auto array = this->CreateArray(fieldInfo.Type);
    if (array)
    {
      fieldInfo.InitializeArray(array, sz, ext);