[Insight-developers] readers and regions

[Damion Shelton]

Ok...

> inputImage->SetRequestedRegionToLargestPossibleRegion() before
> the reader->Update() call, then you have the data you wanted.
> You may still have an indexing problem, however, because it sounds
> like something is indexing off of the LargestPossibleRegion when it
> should be indexing off of the BufferedRegion.

Yup. We changed the code to this and it worked - thanks. We haven't tracked 
down where the region weirdness was coming from.

Re. the filters - here's a code snippet from GradientImageFilter:

  typename TInputImage::RegionType inputRequestedRegion;
  inputRequestedRegion = inputPtr->GetRequestedRegion();

Looking through the rest of the code, it appears that this filter - 
presuming it's a "typical" filter - worries about the requested region 
rather than the buffered region. I.e., the iterators traverse the requested 
regions, and not the buffered regions, if I'm understanding things 
correctly.

So, should filters traverse the requested or buffered regions? Or are they 
the same thing, if the filter is implemented correctly?

Right now we're leaning towards a problem in the blox code propogating 
backward and messing up the regions earlier on, but we're not positive yet.

-Damion-