[Gnome-print] [Fwd: Gnome printing issues]

[Chema Celorio <chema celorio com>]

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• From: Raph Levien <raph acm org>
• To: Lauris Kaplinski <lauris helixcode com>, gnome-hackers nuclecu unam mx
• Subject: Re: Gnome printing issues
• Date: Mon, 11 Sep 2000 11:42:51 -0700

Lauris Kaplinski wrote:
> 
> >    Thus, I now recommend that PDF be used as a default intermediate
> > representation for documents to be printed, and that Ghostscript be
> > used to rasterize the pages for printing to local inkjet printers.
> 
> However good is PDF, I think Gnome shouldn't use it as printing
> meta-format,
> as long as it is controlled by Adobe. File formats, API-s etc. should be
> even more free than programs, IMHO.
> 
> >    There are a number of advantages to using PDF, and no serious
> > disadvantages. The main advantage is flexibility in spooling. In a

I should have phrased this as "no serious technical disadvantages."

> Well, one is. It is proprietary.

Ok, thanks for raising this issue, and also John Trowbridge for raising
the spectre of patents.

It is absolutely true that Adobe has change control over the PDF spec.
In an ideal world, change control for things like file formats would be
held by free organizations. I think the issues are how good a job the
organization does in managing the spec, and how much freedom is
restricted. Historically, Adobe has done well on both counts, although
there is always the possibility for this to change.

So this issue raises several sub-questions:

1. Putting aside the question of _which_ PDL to use, should we be using
a PDL as an intermediate step for printing, or do direct rasterization?

2. What are the technical advantages of using PDF compared with growing
our own?

3. What can we do to minimize our vulnerability in case Adobe becomes
evil in their enforcement of patents?

I believe the answer to (1) is clearly yes. In the local case, it does
not matter much. In the networked case, using a PDL gives you
considerably greater flexibility and avoids potentially serious
performance problems.

While I am definitely sympathetic to the freedom issues, I am reluctant
to grow our own PDL when there's one of extremely high quality already
available. Frankly, it smells like NIH to me. I question whether we have
the resources and commitment to build a PDL that comes close to the
quality of PDF. It's not trivial, guys! Lastly, we give up
interoperability with the rest of the world. I realize that people may
have differing senses of the importance of this interoperability -
purists will say "freedom is much more important", while others will be
out there developing interesting software like Samba, Wine, wv,
gnapster, x86 compiler back-ends for gcc, etc.

Now, what do we do if Adobe enforces their patent? My favorite idea is
to define a patent-free profile of PDF 1.4. My feeling is that PDF 1.3
plus a subset of the PDF 1.4 transparency features (the ca and CA, and
SMask entries in the extended graphics state, plus SMask images, most
likely), would meet these needs. I believe this is a good feature set
for Gnome Print, and it allows a totally free implementation. Much
useful interoperability is preserved. Particularly, it should be
possible to produce a document from Gnome, and have it spooled, viewed,
and managed on other systems. The reverse direction seems to me more of
a Ghostscript issue than one for Gnome Print.

I will continue to lobby Adobe to keep PDF 1.4 open for free
implementation. I have some experience doing this, incidentally. For
example, I lobbied the W3C (a closed consortium of proprietary
companies) to keep patented font technology out of SVG. We do need to be
fighting these battles, but I think it's a legitimate question whether
the best way to do that is to NIH our own incompatible file formats.

Raph

-- 
Raph Levien <raph@artofcode.com>  |  artofcode LLC  |  www.artofcode.com

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