[SciPy-user] The IO library and image file formats -- compare with with PIL
Fri Apr 18 09:31:34 CDT 2008
> Ultimately we has to consider a fork of PIL.
> Do you guys know, if this is allowed -- per the PIL license !?
> Of course this would be super sub optimal,
> but then, it's effectively what I have right now -- and you have your
> own version .....
> To summerize: numpy can probably do many things of PIL already better
> -- I'm talking about all the transformation stuff of course.
> So only the file IO would have to get forked out -- to scipy for
> example ;-)
I have my own "internal fork" of PIL that I've been calling "PIL-
lite". I tore out everything except the file IO, and I fixed that to
handle 16-bit files correctly on all endian machines, and to have a
more robust array interface.
IIRC, PIL is BSD-licensed (or BSD-compatible), so the fork should be
OK to re-distribute.
Now, part of the reason that we may have heard nothing about the PIL
patches we've submitted variously is that I understand that they're
doing a big re-write of PIL, and in particular, its memory handling,
that should address these sort of issues. However, we all know how
well "big rewrites" go...
If people wanted to make a proper "fork" of PIL into a numpy-
compatible image IO layer, I would be all for that. I'd be happy to
donate "PIL-lite" as a starting point. Now, the file IO in PIL is a
bit circuitous -- files are initially read by pure-Python code that
determines the file type, etc. This information is then passed to
(brittle and ugly) C code to unpack and swizzle the bits as necessary,
and pack them into the PIL structs in memory.
I think that basically all of what PIL does, bit-twiddling-wise, could
be done with numpy. So really, what's needed is to take the pure-
Python "file format reading" functionality from PIL (with my
modifications thereof to handle 16-bit files better, and Stéfan and
Sebastian's modifications for other functionality, etc), and then
attach it to a layer that uses Python and numpy to actually read the
bits out of the files and directly into numpy arrays.
I've been meaning to do this for a while, but just haven't gotten
around to it. I think it will be a surprisingly small amount of code
needed around PIL's python file format readers.
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