[vtkusers] Snapshot of Render Window

[Martin Baumann]

Hi,

for taking snapshots of a render window I do the following

void save_as_picture(const QString& file)
{
  setActiveWindow();
  raise();

  png_writer->SetFileName((const char*)file);
  ren_win->Render();

  win2image->Modified();
  win2image->Update();

  png_writer->Modified();
  png_writer->Write();
}

If any window is in front of that render window a picture is created 
that shows the
other window - not the render window.
What can you commend me to do?

Thanks, M.B.