[SciPy-User] FreeImage <-> numpy IO wrappers

[Sebastian Haase]

Hi Zach,

this sounds exciting and I might find some time to try it out ...
BTW, the Python image-sig  should not be a "PIL only" mailing list. So
(eventually) I feel, this issue could be brought up there, too.

But most importantly, I think it would be great to finally have a
"small footprint" image-format library that does not try to reproduce
all kinds of operations that we can do easily in numpy.

Do you know if FreeImage does anything via memory-mapping ? I'm mostly
interested in TIFF-memmap, which exists according to libtif, but I
have now idea how useful it is .....  (I need memmap for GB-size
multipage images)

Thanks,
Sebastian




On Wed, May 12, 2010 at 7:56 AM, Zachary Pincus <zachary.pincus at yale.edu> wrote:
> Hi all,
>
> I've been meaning for a long time to look into cobbling together some
> non-broken, maintainable (e.g. non-PIL) image IO library that can deal
> with scientific (16-bit and floating-point) image formats. I finally
> bit the bullet yesterday and whipped together a ctypes wrapper for the
> FreeImage library. (FreeImage is portable and largely if not entirely
> dependency-free; Windows binaries are available and it compiles
> cleanly on os x as well as other unixes: http://freeimage.sourceforge.net/
>  Check out the manual: http://downloads.sourceforge.net/freeimage/FreeImage3131.pdf
>  , particularly the appendix that shows the supported image types and
> pixel formats: pretty impressive. Also note that there is a
> "FreeImagePy" project that has ctypes wrappers for FreeImage, but the
> code is... idiosyncratic... and doesn't interface with numpy anyway.)
>
> The underlying library and wrappers I wrote support reading and
> writing of greyscale, RGB, and RGBA images with 8- and 16-bit int/uint
> and 32-bit float pixels, as well as greyscale images with 64-bit float
> and 128-bit complex pixels. (The TIFF spec supports all of these, at
> least, as does FreeImage, but most other TIFF readers probably don't.
> The PNG format itself is a bit more limited, but FreeImage can read/
> write everything in the spec, I think. Most other formats are 8-bit
> only.) Multipage image IO is also supported, and there's currently a
> bit of support for reading EXIF tags, which could easily be beefed up.
>
> The wrapper code is pretty compact and straightforward, and the
> FreeImage library seems pretty robust and simple (once one notes that
> it uses BGRA ordering on little-endian systems). Overall I feel a lot
> better about using this than dealing with PIL and its broken memory
> model and worse patch-acceptance track record.
>
> If anyone wants to test the wrappers out, I'll send you the code.
> Going forward, I'll look into getting this into the scikits image IO
> system, but I don't really have free cycles for that right now.
>
> Zach
>
> PS. FreeImage is dual licensed: GPL and a "FreeImage license", the
> latter of which I have no idea if is BSD compatible -- it says it's
> "less restrictive" than GPL but I'm unable to parse the license's many
> clauses. In any case, as long as users are required to provide their
> own FreeImage dll/so/dylib, it's not really a problem.
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