Jasper (jpeg-2000): reasons to use it

Ken Moffat zarniwhoop at ntlworld.com
Tue Oct 7 11:47:49 PDT 2008


On Fri, Oct 03, 2008 at 12:46:25PM +0100, Ken Moffat wrote:
>  I built gtk+-2.14.3 last night, and was more than a little surprised
> to find that it now expects jasper (or, failing that,
> --without-libjasper ) the configure output is very helpful, but I
> had assumed jpeg2000 was another thing that hardly anybody used.
> 
>  Usually, passing --without-something is a sign that functionality
> will be limited.  So, will I be missing anything useful ?
> 
 Thanks to Dan and Simon for the advice, but I now think it's a good
idea to change my mind and use jasper.

 As part of my general desktop upgrade, I went over to
gnu-ghostscript (8.63) from espgs, so that I can build libspectre
for okular [ if I ever get that far ! ].  Dropped it in without
thinking too much, discovered that printing was broken.  Turned out
I'd only done the soinstall, not the install (one does shared libs,
headers, some progs but not 'gs', scripts, docs, the other does gs,
cups filters etc, plus the scripts and docs).  So, i didn't have the
pstoraster filter.  But by that stage I was looking at the detail of
gnu ghostscript.

 Turns out it ships a copy of libjasper, as well as copies of zlib,
jpeglib, libpng, and jbig2dec.  For the moment, I'm sticking with
the bundled jbig2dec - it was developed for afl-ghostscript, but the
last release was more than 2 years ago so I guess nothing else will
use it and hopefully gnu-gs will look after it if vulnerabilities
are found.  The jpeg, libpng, zlib libraries correctly pick up the
shared system libraries, although the defines and comments suggest
otherwise, but the enclosed jasper is built if present.  It's a
version of 1.701 instead of 1.900.  Needs a patch from fedora to
compile against 1.900, as well as deleting the bundled source.  The
alternative is to do without the jasper code in gs [ which will
cause some pdfs which contain jpeg2000 images to not print the
images ], or to use a non-shared old version.

 Jasper is also usable by ImageMagick, and probably others.  Since
someone (Amazon at least) is using jpeg2000 images, I think they are
worth having.

 Meanwhile, I still can't print - cups has lost the option to "set
printer options" and can't send a test page without a default
printer.  Using lpotions appeared to set it, but also showed that it
was set for letter paper.  Time to dig deeper into cups.  Now I
remember why I stick with the working versions for my desktop ;)

ĸen
-- 
das eine Mal als Tragödie, das andere Mal als Farce



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