[pdftex] compression of bitmaps

[Ben Crowell]

Hi all -- I'm new on this list, so I hope I'm not wasting
bandwidth with a totally naive question. I've been trying
to learn more about what can be done to improve the compression
of pdflatex output that contains a lot of bitmapped graphics.
I have an open-source book,
(http://www.lightandmatter.com/area1sn.html)
which I'm compiling with pdflatex (TeXShop, which uses teTeX). The
pdflatex output is 25 Mb, whereas Distiller 3.0 produces 6 Mb!
(You might wonder why I don't just use Distiller. Well, besides
preferring open-source software, there's a bug in Distiller that
mangles any text that occurs within my figures. Yeah, I /could/
pay Adobe $100 for an upgrade to the latest Distiller, and see
if it fixed the bug :-p)

 From what I understand, Distiller can use the JPEG compression
algorithm to compress bitmapped graphics, but pdflatex only
does compression of text (using the flate algorithm).

Are there are plans to implement this type of compression in
pdflatex? Famous last words ;-), but it seems like it shouldn't
be all that hard. JPEG seems to be patent-free, as long as you
avoid some proprietary extensions, and pdftex already accepts
JPEG input. If it isn't already being worked on, I'm toying with
the idea of trying to implement it myself -- actually I'd
probably first just try to implement a PDF->PDF filter, which
would keep me from having to get over the hump of compiling
all of pdftex. (I use MacOS X, which has a nice set of
BSD & GNU development tools, but most software made to compile
on Linux doesn't just compile without modification.)

	Ben Crowell
	crowell01 at lightandmatter.SPAM IS NAUGHTY.com