vtkImageViewer shouldn't crash when no render window
Hello, In vtkImageViewer2, "RenderWindow" member is almost always checked before use. The almost being when not checked in "vtkImageViewer2::Render" when the window size is set.
Even though the class is meant for displaying (hence embedding the render window), a crash behaviour shouldn't be allowed (in my opinion). Maybe add a log (error or warning) ?
How to reproduce:
- Setup a classic "vtkImageViewer2" use case (like in ReadDICOMSeries example)
- Call "SetRenderWindow" with nullptr
- It will crash at first render