Method RenderOverlay

Rendering/Image/vtkImageStack.cxx:422–479

------------------------------------------------------------------------------

//------------------------------------------------------------------------------
int vtkImageStack::RenderOverlay(vtkViewport* viewport)
{
  vtkDebugMacro(<< "vtkImageStack::RenderOverlay");

  if (!this->IsIdentity)
  {
    this->PokeMatrices(this->GetMatrix());
  }

  int rendered = 0;
  vtkImageSlice* image = nullptr;
  vtkCollectionSimpleIterator pit;
  vtkIdType n = 0;
  this->Images->InitTraversal(pit);
  while ((image = this->Images->GetNextImage(pit)) != nullptr)
  {
    n += (image->GetVisibility() != 0);
  }
  double renderTime = this->AllocatedRenderTime / (n + (n == 0));

  if (n == 1)
  {
    // no multi-pass if only one image
    this->Images->InitTraversal(pit);
    while ((image = this->Images->GetNextImage(pit)) != nullptr)
    {
      if (image->GetVisibility())
      {
        image->SetAllocatedRenderTime(renderTime, viewport);
        rendered = image->RenderOverlay(viewport);
      }
    }
  }
  else
  {
    for (int pass = 1; pass < 3; pass++)
    {
      this->Images->InitTraversal(pit);
      while ((image = this->Images->GetNextImage(pit)) != nullptr)
      {
        if (image->GetVisibility())
        {
          image->SetAllocatedRenderTime(renderTime, viewport);
          image->SetStackedImagePass(pass);
          rendered |= image->RenderOverlay(viewport);
          image->SetStackedImagePass(-1);
        }
      }
    }
  }

  if (!this->IsIdentity)
  {
    this->PokeMatrices(nullptr);
  }

  return rendered;
}