[pdftex] compression of bitmaps

[Jiri Osoba]

PDFTeX uses Deflate (ZIP) compression to compress text and bitmaps (TIFFs, PNGs).

It can use JPG images directly - they are stored in PDF with the same size.

You can include PDFs - compression is not changed - probably the best way - it's fast and you can tune compression (Deflate, JPG, CCIT...) to save as much space as possible.

Jiri.

----- Original Message ----- 
From: Ben Crowell <crowell01 at lightandmatter.com>
To: <pdftex at tug.org>
Sent: Friday, August 10, 2001 3:25 AM
Subject: [pdftex] compression of bitmaps


> 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
> 
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