Re: [xsl] XSL-FO versus PostScript
Subject: Re: [xsl] XSL-FO versus PostScript|
From: "W. Eliot Kimber" <eliot@xxxxxxxxxx>
Date: Fri, 28 Feb 2003 13:10:37 -0800
David Carlisle wrote:
Having said that, while I am a supporter of FO, given that most of my
documents are English and/or mathematics (ie no vertical or
bi-directional text no fancy bordered effects) I would always
(at the moment) print XML via XSLT stylesheet to latex rather than
to FO. (see the pdf versions of the MathML spec for example)
It's hard to know in my case though whether that's based on
a real unbiased assesment or just a product of having latex
somewhere burried deep into my subconcious after having worked on it for
15 years or so.
Modulo limitations in the XSL 1.0 spec, a good FO implementation should
be able to produce results comparable with TeX (and of course, there are
two TeX-based FO implementations, Sebastian's and Epic 4.3, which is
TeX-based underneath). For MathML, there's no reason in theory that one
couldn't integrate a MathML-to-PostScript process as part of a larger FO
process, possibly even leveraging existing TeX-based MathML processing.
Obviously, TeX has been around a long time and is very mature. FO
implementations are much younger and therefore are less complete and
tuned, but there's no *inherent* limitation in the ability of FO-based
systems to produce typographic results as good as those produced by any
other system. All the main FO implementations are being aggressively
developed and refined by their developers.
This has probably been covered already, but it's also important to point
out that PostScript, by itself, provides no facilities for doing
typesetting--that is entirely handled by whatever it is that generates
the PostScript. PostScript is a graphics language--it's up to a
higher-level system to use that language to place marks on pages
appropriately. To that degree it's not even meaningful to compare XSL-FO
(or TeX) and PostScript.
The value of XSL-FO accrues from its generality and abstraction, which
allows developers of presentations to leverage the hard work of FO
implementators, who in turn can leverage the hard work of typesetting
engine implementors (if they use an existing typesetting system like
TeX). This value includes ease of development and maintenance, as well
as vendor independence, at the cost of some limitations in
functionality. If you can live within these limitations then the value
of FO is very high from a business standpoint. If you can't, then you
have no choice but to look for other technological solutions.
For individuals implementating essentially a one-off solution to a
problem it might make more sense to craft a TeX-based solution, for
example, or even to craft direct generation of PostScript, especially if
you have more time than money.
For enterprises, which tend to have more money than time, concerns like
cost of implementation, cost of ongoing maintenance, limiting project
risks, and protection from proprietary lock-in and dependency become
much more important criteria, and within that equation, FO-based
solutions look very attractive if the rendition requirements can be met.
It can be the difference between a 10K Euro solution and 100K or 500K
Euro solution to the same problem.
W. Eliot Kimber, eliot@xxxxxxxxxx
Consultant, ISOGEN International
1016 La Posada Dr., Suite 240
Austin, TX 78752 Phone: 512.656.4139
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