[vtkusers] ImageData WholeExtent/Dimensions problem

[John Biddiscombe]

Lisa & Charles,

I suspect I'm doing something bad.
I'm using my RPD pipeline editor and the filters are connected to
an inspector object, the inspector always does

input->SetUpdateExtentToWholeExtent()
input->Update();

because I've had my fingers burnt too many times before with dodgy
extents (as Charles will have noted - c.f. ImageClip etc etc).

Inside the filter, I've basically copied the code from
ImageShrink3D because its doing almost exactly the same as my
filter with the difference that mine has 2 inputs and combines
them before averaging - AND I'm not using the multithreaded
code...

In ExecuteInformation, I compute the output extents and set things
up, then in execute I set the scalars and off I go. I've solved
the problem of the dimensions being 0,0,0 by simply ignoring them
and using the WholeExtent instead (I'm not multi-threading so no
problem here). However, it does seem that the dimension is staying
at 0,0,0 ALL the time (but only in my filters!). I'm confused. I
guess the fault is mine own so don't waste time looking for a bug
which may not exist. If I haven't fixed it by Monday, then I'll
start whining properly.

thanks & ttfn

John B