[vtkusers] update confusion

Sven sven.prevrhal at oarg.ucsf.edu
Mon Oct 30 21:15:28 EST 2000

Thanks -great (I do not use reslice right now)!
When I use UpdateWholeExtent often enough, it seems to work. I guess it gets
a little tricky because by GUI (meaning anytime) I control what is displayed
in the viewer (output of different image processing steps in my pipeline).

Here's another related question: How can I render only a certain portion of
the ImageViewer and leave the other portions alone?

Thanks again,

-----Original Message-----
From: David Gobbi [mailto:dgobbi at irus.rri.on.ca]
Sent: Monday, October 30, 2000 5:26 PM
To: Sebastien BARRE
Cc: Sven; Vtk Mailing List
Subject: Re: [vtkusers] update confusion

On Tue, 31 Oct 2000, Sebastien BARRE wrote:

> At 30/10/00 16:35, Sven wrote:
> >How can I have the chain execute once for the whole volume independent
> >on what's on the screen?
> if your object is named "reader", then :
>          reader UpdateWholeExtent
> will do the trick by reading the whole stuff in memory.
> if you use vtkImageReslice to display a slice from a volume, you do not
> need that, but if you use two different vtkImageReslice (or objects) on
> same reader, then use UpdateWholeExtent once.

Whoa, not quite true.  If you use vtkImageReslice to display a slice from
the volume, you should still call 'reader UpdateWholeExtent.'  There are
some circumstances that cause vtkImageReslice to Update the whole extent
of its input, but usually it only Updates a portion of its input.

 - David

  David Gobbi, MSc                    dgobbi at irus.rri.on.ca
  Advanced Imaging Research Group
  Robarts Research Institute, University of Western Ontario

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