[vtkusers] vtkImageImportFromArray.py problem on Debian Linux

[Prabhu Ramachandran]

>>>>> "Tony" == Tony Willis <Tony.Willis at nrc-cnrc.gc.ca> writes:

    Tony> Hi All A bit of background - I want to use VTK to visualize
    Tony> python 3D numarrays.  The contents of these arrays can
    Tony> change as a function of time, and when they do, I want the
    Tony> display to be updated accordingly. However I'm encountering
    Tony> a problem in the visualization because the conversion of
    Tony> these numarrays into a VTK data type is failing under Debian
    Tony> Linux.

Here is a quick hint.  Numarray arrays by default don't support the
buffer protocol (which is how the voidpointer magic happens).  So,
you'll need to use the array's '_data' attribute.  For example:

 f = numarray.arange(0, 10, 0.1)
 print f._data

Pass this instead of f itself.  BTW, I asked the developers on the
numarray list to provide the buffer protocol for numarray arrays also
but that has not happened. :(

However, this in itself won't fix your code since you'll need to
modify vtkImageImportFromArray for this (unless you write code to do
this yourself -- the basics are really simple and you really don't
need all the stuff that vtkImageImportFromArray does).

OTOH, the easiest solution would be to use Numeric instead of
numarray.  Your code runs fine if you simply replace

from numarray import *
with
from Numeric import *

and
image_numarray_test = ones((num_arrays,array_dim,array_dim),type=Float32)
with
image_numarray_test = ones((num_arrays,array_dim,array_dim),typecode=Float32)


cheers,
prabhu