Official PDF URLs for X Specs

Markus Kuhn Markus.Kuhn at
Fri Apr 25 07:01:16 PDT 2008

Chuck Robey wrote on 2008-04-25 00:26 UTC:
> > Why is the archaic PS.gz format used and not the *much* more convenient
> > and portable PDF?
> This part seems almost like you had some sort of private goals operating.  You
> know as well as I that PS is incredibly simple to convert to and from pdf,

Being in charge of a non-trivial amount of PS->PDF conversion (see, my experience has been
that this is certainly not as trivial as you may make it sound, *if* you want
to do it properly. As just one trivial supporting data point, take the
fact that the top/bottom page margins of

are obviously wrong right now. (My guess would be: the coordinate system
was accidentally shifted upwards by the famous 19 mm height difference
between U.S. "Letter" and ISO A4 format; a most common kind of pitfall
that won't vanish completely before North Americans finally adopt
international standard paper sizes ... *sigh*.)

> but beyond that, pdf tends to want to find a way to make you PAY for the tools,
> where all the PS stuff is public.

You describe the situation over a decade ago. The situation is today
closer to the opposite: many formerly popular free tools for dealing
with PostScript are no longer well supported and have been abandoned as
everyone has moved to PDF, e.g. there isn't even a commonly deployed web
browser-plugin to view PS.gz! Things have changed, e.g. PDF is no longer
owned by Adobe: they have handed maintenance of the spec over to ISO
(ISO 32000), and there are nearly half a dozen independent open-source
implementations around (can you name more than one for PostScript?).


Moving from PS.gz to PDF is a fairly simple short-term cleanup
(involving adding a ghostscript call in some makefiles and setting up
some easy-to-reference canonical long-term URLs) that would make it so
much easier to refer to the documentation in web pages. I'm glad to hear
that there are also plans to standardize the source formats for X11
documentation in the long term; troff certainly has lost its place.


Markus Kuhn, Computer Laboratory, University of Cambridge || CB3 0FD, Great Britain

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