Karim Belabas on Mon, 16 Jan 2006 19:15:07 +0100

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Re: Graphic support in CVS

* Ilya Zakharevich [2005-11-24 05:38]:
> Looks like support for output via "Gnuplot terminals" has slipped via
> the cracks.  With August CVS version I can see
>   --graphic=<gr> graphic library used (default X11) (none X11 Qt
>         gnuplot gnuplot-dynamic builtin.X11-gnuplot
>         builtin.X11-gnuplot-dynamic)
> With current CVS the supported list is much shorter.

I tried unsuccessfully to install Term::Gnuplot on 2 different Linux machines:
(Fedora and Mandriva distributions), and both failed to build.

Then I tried to build and use a libgnuplot from gnuplot-4, and discovered 
it would require major work to do this due to rewritten internals.

Gnuplot support 
1) complicated quite a bit the Configure scripts, and the relevant graphing code
( swapping functions with #define magic to support simulatneously two
graphing engines )

2) did not bring in a major improvement compared to the other plotting engines

3) was at the best of times quite difficult to build ( I failed more often
than not when trying to compile gnuplot support ).

4) was not trivial to integrate with the new implementation of 
rectdraw0 / gen_rectdraw0.

5) did not seem to have many users.

6) brought in legal difficulties [ the gnuplot license is not so permissive ]

So I decided to dump it for the pari distribution (after a lot of work
to understand how it worked and how I could try to adapt it).

In retrospect, I don't think low-level integration with the gnuplot sources
to command graphing terminals from within gp was a viable target.

It would still be very interesting to output (to file) a description of some
plot in the gnuplot language ( to be fed to an independant instance of the
gnuplot interpreter, possibly after some hand editing ). But using
undocumented, hackish gnuplot internals was doomed to fail.



P.S: Sorry for the very late answers. I have been very busy with
non-PARI-related stuff...
Karim Belabas                  Tel: (+33) (0)5 40 00 26 17
Universite Bordeaux 1          Fax: (+33) (0)5 40 00 69 50
351, cours de la Liberation    http://www.math.u-bordeaux.fr/~belabas/
F-33405 Talence (France)       http://pari.math.u-bordeaux.fr/  [PARI/GP]