[vtkusers] Z-Order of vtkRenderer,vtkImageActor,vtkTextActor

[Thomas Lambertz]

Hi there,

i have a problem with providing some text-information for dicom-slices.

Each slice is represented by a vtkImageActor and a vtkRenderer. All 
vtkRenderers are arranged like a chessboard using their SetViewport() 
method. There is no overlapping and all went fine.

I thought i could add some text-information by adding another 
vtkRenderer with a vtkTextActor. This renderer could use the hole 
RenderWindow - (SetViewport(0.0,0.0,1.0,1.0)). But whatever order of 
RenderWindow->AddRenderer() i choose - the text is never visible. By 
omitting the slice-renderer i see the text - so the TextActor/Renderer 
seemes to work (and is only hidden behind them ?).
But:
By adding the TextActor to each sliceRenderer the text is visible. But 
that´s not a real solution as all sliceRenderer are restricted by their 
viewport-settings - and i dont want to add the TextActor to all of them 
only to see the hole text.

It looks to me as i am struggling with the z-order of these renderers. 
The order of adding the renderer seemes not to solve my problem.
What am i doing wrong ? Can i set an z-order by hand ? Should i use 
another classes for my problem ?

Any suggestions are very appreciated.

Thanks in advance,
Tom