On 2010-03-27 08:17:46 -0700, Alain Ketterlin said:
Stephen Hansen <apt.shan...@gmail.invalid> writes:
If not, are there any decent other image libraries out there
that anyone's familiar with? The only one I could find was
PythonMagick, which seems completely undocumented. Or I'm blind.
I don't know PythonMagick, but it is based on ImageMagick, which is kind
of a swiss-knife in image manipulation and conversion. You could try the
standalone tools first, to see if you get what you want/need.
Well, I know it -can- do what I need, except the subprocess business
isn't something I want to deal with. And the library seems utterly
undocumented. :(
Hmm, a 16x16 image. Don't expect much from the most sophisticated
formats (e.g, PNG), because their overhead (headers etc.) may well be
above the size of the data. Compression isn't usually targeted at small
files.
Yeah, I don't expect much from PNG. The images are very small but I
might be sending a LOT of them over a pipe which is fairly tight, so
50-60 bytes matters. That's why I selected GIF.
(BTW: "slight tweaking" may have an effect on file-size if it introduces
new colors, because GIF uses a color-table. I guess you know all this.)
Yeah, I know this is possible, which is why the tweaking was to be very
careful: these images all have only a couple indexed colors each, and I
should be able to do the tweaks and not increase the size excessively.
However, the problem is: I left out all the tweaks and it still
exploded in size.
Just opening, and then saving the same file with no changes at all,
resulted in a 72 byte file growing to 920.
I thought it was GIF87a vs GIF89a... but have since come to determine
it doesn't appear to be. I decided to give PNG a try again, since those
extra 50 bytes *matter*, but if I can't get GIF to work, 50 is better
then 900. Unfortunately, I hit the same wall there.
If I convert these itty-bitty images into PNG, they're about 120 bytes
or so. Opening one in PNG, making no changes, and saving, results in
the new file being 900 bytes too :(
So I wonder if there's just some hyper-optimization Photoshop does that
PIL can't round-trip.
GIF uses the LZW algorithm, and so does zip and gzip (the latter with an
additional layer of Huffmann coding). If your images are of fixed size,
you _may_ be better off compressing the raw data with a general purpose
compressor (i.e., gzip). Check the packages gzip and zlib.
Hm. I hadn't thought of compressing the saved version. I could do that,
I suppose: it just seems there is so much extra stuff which shouldn't
be needed that's being saved out.
--
--S
... p.s: change the ".invalid" to ".com" in email address to reply privately.
--
http://mail.python.org/mailman/listinfo/python-list
