Method UpdateHoverText

Views/Infovis/vtkRenderView.cxx:525–578

}

void vtkRenderView::UpdateHoverText()
{
  this->UpdatePickRender();

  int pos[2] = { 0, 0 };
  unsigned int upos[2] = { 0, 0 };
  double loc[2] = { 0.0, 0.0 };
  if (this->RenderWindow->GetInteractor())
  {
    this->RenderWindow->GetInteractor()->GetEventPosition(pos);
    loc[0] = pos[0];
    loc[1] = pos[1];
    upos[0] = static_cast<unsigned int>(pos[0]);
    upos[1] = static_cast<unsigned int>(pos[1]);
  }
  this->Balloon->EndWidgetInteraction(loc);

  // The number of pixels away from the pointer to search for hovered objects.
  int hoverTol = 3;

  // Retrieve the hovered cell from the saved buffer.
  vtkHardwareSelector::PixelInformation info = this->Selector->GetPixelInformation(upos, hoverTol);
  vtkIdType cell = info.AttributeID;
  vtkProp* prop = info.Prop;
  if (prop == nullptr || cell == -1)
  {
    this->Balloon->SetBalloonText("");
    return;
  }

  // For debugging
  // std::ostringstream oss;
  // oss << "prop: " << prop << " cell: " << cell;
  // this->Balloon->SetBalloonText(oss.str().c_str());
  // this->Balloon->StartWidgetInteraction(loc);

  std::string hoverText;
  for (int i = 0; i < this->GetNumberOfRepresentations(); ++i)
  {
    vtkRenderedRepresentation* rep =
      vtkRenderedRepresentation::SafeDownCast(this->GetRepresentation(i));
    if (rep && this->RenderWindow->GetInteractor())
    {
      hoverText = rep->GetHoverString(this, prop, cell);
      if (!hoverText.empty())
      {
        break;
      }
    }
  }
  this->Balloon->SetBalloonText(hoverText.c_str());
  this->Balloon->StartWidgetInteraction(loc);
  this->InvokeEvent(vtkCommand::HoverEvent, &hoverText);
}

void vtkRenderView::ApplyViewTheme(vtkViewTheme* theme)
{