[Pyrex] PyRex + PIL

[G. Kunze]

Hi,

I recently (yesterday) started playing around with PyRex. I've succeeded 
in wrapping a small C library using the tutorial and some other 
info/examples I've found on the web and I must say it's great, a lot 
easier than I expected.

Now I'm trying to add features to the wrapper, the library needs small 
bitmaps, I currently provide  the library those bitmaps with a small 
extension type containing a byte-array and supporting get_pixel and 
set_pixel methods. Needless to say, this is very slow and not very 
useful. Therefore I wanted to be able to pass Image-objects from the 
Python Image Library to the library wrapper and have it use it's raster 
data.

Since the library wants the data contained in Imaging->image exactly, I 
figure I don't even have to memcpy it. So now I'm trying to include the 
Image extension type of the PIL library in my wrapper, and failing.

Getting an extension type from the PIL library seems to be quite a bit 
more complex than the complexobject-example in the documentation. This 
is the information I have extracted from the PIL sources (my C skills 
have rusted over the years of my Python addiction):

The 'Image'-class is an ordinary Python-class (not an extension type) 
which contains an attribute 'im' which is the extension type 'ImagingCore'.
The PyTypeObject is 'Imaging_Type', and the associated structure 
containing the PyObject-struct is 'ImagingObject'. This is defined in 
_imaging.c.
'ImagingObject' contains an 'Imaging'-type, the 'Imaging'-type is 
defined in 'libImaging/Imaging.h' and is a typedef-ed 
'ImagingMemoryInstance'-pointer, also declared in the same header file. 
The 'ImagingMemoryInstance' contains the 'image'-pointer I want to use.

However I try to map these findings onto PyRex, I can't seem to get it 
to work. I was hoping someone has already used the PIL in his/her 
project and could give me an example of how to do it. Or shouldn't this 
be the case I'd really like some tips on how to proceed.

Regards,

G. Kunze