[vtkusers] vtkUnsignedCharArray from python

[David Gobbi]

Hi Kyle,

The VTK data arrays support the python "buffer" protocol, which can be
used to get raw access to the array.  If you have numpy, you can do
the following:

a = numpy.fromstring(image.GetPointData().GetScalars(), 'uint8')

Also, in python 2.6, you can get "raw" access to the data like this:

b = buffer(image.GetPointData().GetScalars())

You can use str(b) to convert the buffer to a string, but for most
purposes you should be able to use the buffer directly without
conversion to a string.

  David


On Thu, Dec 30, 2010 at 9:34 PM, Kyle Cronan <kyle at cronangraf.com> wrote:
> Hi all,
>
> The python wrapper doesn't seem to give any way to convert a
> vtkUnsignedCharArray (such as returned by an image output object that
> is set to output into memory) into a python string.  Am I right about
> that?
>
> It would maybe work if there was something like ExportToVoidPointer
> that did the memory allocation for you.  I took a look at the python
> wrapper generator but it was beyond me how that all works.  Is there
> an easy fix?  In the mean time I will write to a temp file and just
> read that back in.
>
> Thanks,
> Kyle
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