Re: images, notations, backends

[Matthias Clasen <clasen@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>]

> 
> I've been thinking about a rather difficult problem -- image handling
> in SGML.  As you now, different backends like different image formats.
> For instance, if you're producing DVI or PS with JadeTeX, you use EPS
> format.  If you're producing PDF (with PDFJadeTeX), your figures need
> to be in PDF format.
> 
> Reading Goldfarb's "SGML Handbook", there seems to be a rather
> amorphous and foggy notion that you can use "Dual-role" public text
> (system and public declarations), such that the system identifier
> points to a program which can intepret the output (looking at 6.4.4 on
> page 188):
> 
>   The external identifier of a data content notation, for example,
>   could include both a public identifier of a publication that
>   describes the notation, and a system identifier of a program that
>   will be called to interpret data that conforms to the notation.
> 
> My problem is that I would like a build system which, based on the
> output, pre-processes figures. I can teach the system what figures to
> create based on what output format is desired.  But then I also have to tell the SGML source what image file suffix to expect.
> 
> I was wondering if there's a more standards based way to do it, or if
> it makes sense to have OpenJade (or anotehr SGML processor) look for
> external data with NOTATION attributes and run a certain program with
> certain arguments or some such (sdc used to do this).

I think it would make sense in an SGML application, not in the SGML
parser itself. I have patched psgmls to do this, eg call gimp if the 
user wants to edit an external entity whose notation is an image format
(I think that patch actually made it into psgml-1.2.0).


-- 
Matthias Clasen, 
Tel. 0761/203-5606
Email: clasen@xxxxxxxxxxxxxxxxxxxxxxxxxx
Mathematisches Institut, Albert-Ludwigs-Universitaet Freiburg



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