Re: [Plplot-general] replot: buffer not available (thread started as "post processing with plrender")

[Salazar, G. P. <ger...@si...>]

Alan:

Thanks for such a complete report.

I guess there are too many tricks to make plreplot work from =
Fortran...tricks that will eventually trip somebody over at some point; =
not to mention that, like I said before, I am going =
multi-platform...Solaris, Linux, Windows...so the xwin thing may not fly =
to good there. Also, I mentioned earlier that we couldn't make the =
plplot installation befriend Active State's tcl installation, which =
leaves tk out of the picture, too.  I was already refered to some =
instructions, but I have no re-visited that link.

I will stick with dual streams, since it works without any tricks.

Thanks, again.

Germ=E1n
=20

-----Original Message-----
From: Alan W. Irwin [mailto:ir...@be...]=20
Sent: Tuesday, September 04, 2007 4:15 PM
To: Salazar, German P21322
Cc: plp...@li...
Subject: Re: [Plplot-general] replot: buffer not available (thread =
started as "post processing with plrender")

On 2007-09-04 14:32-0400 Salazar, German P21322 wrote:

> Well, I am back, although I have now changed the topic title to =
"replot".
>
> Like I said before, my ultimate objective is to have a single ps =
document where, say, pages 1 and 3 are in landscape and page 2 in =
portrait; that, I can already do with a small script if I have the two =
original files, one with all pages in landscape and another with all =
pages in portrait...then, I can pick and choose what pages I want in the =
final document.
>
> Here is the thing:
> I have managed to plot in landscape (no surprise there, that is the =
default).
> I have managed to plot in portrait, for real; the one option that does =
it is command line argument -portrait, and not plsdiori.
> I have also managed to do both things above in a single run by opening =
two streams, one left alone (landscape) and another set to protrait.  =
This way I end up with I what need.
>
> So, basically, I am done.
>
> The thing is that I see a couple of C examples with the plreplot() =
command and I thought that was a lot more elegant than having to open =
two streams at the begining, keep switching/plotting to both streams at =
all times, and closing both streams at the end. Just doing everything =
once and saving a copy of it at the end seems simpler, if I can change =
from landscape to portrait right before the replot...except that I =
couldn't get there, since plreplot() will not work for me from =
Fortran...curiously enough, there are two C examples that use plreplot() =
but none in Fortran...does this mean something, i.e., plreplot does not =
work from fortran?
>
> Here is the message:
>
> *** PLPLOT WARNING ***
> plreplot: plot buffer not available

I got this to work, but only under special circumstances for both the C =
and
Fortran 77 version of our examples.

Here is the fortran patch for example 1.
****************
--- x01f.f_original     2007-09-04 12:01:35.000000000 -0700
+++ x01f.f      2007-09-04 12:36:20.000000000 -0700
@@ -28,6 +28,7 @@
        integer digmax
        integer PL_PARSE_FULL
        parameter(PL_PARSE_FULL =3D 1)
+      integer cur_strm, new_strm
  C      some fortran compilers demand typing of intrinsic lnblnk, and
  C      although this is not demanded on g77 it also works there.
        integer lnblnk
@@ -72,6 +73,19 @@

        call plot2()
        call plot3()
+      ! Test whether can work with streams and plreplot from fortran.
+      call plgstrm(cur_strm)!      /*get current stream */
+      call plmkstrm(new_strm)!   /* create a new one */=20
+=20
+      call plsfnam("test_stream.ps")!       /* file name */
+      call plsdev("psc")!         /* device type */
+
+      call plcpstrm(cur_strm, 0)! /* copy old stream parameters to new =
stream */
+      call plreplot()!      /* do the save by replaying the plot buffer =
*/
+      call plend1()!              /* finish the device */
+
+      call plsstrm(cur_strm)!     /* return to previous stream */
+
  C      Don't forget to call PLEND to finish off!

        call plend()
****************

Ordinarily, I would like to make this patch part of the fortran version =
of
example 1, but plMergeOpts (which allows parsing of extra command-line
options for any given application) is not part of the Fortran interface =
so
there is no easy way to parse the -save option for example 1 in fortran.
Instead, I have used a fixed name (test_stream.ps) here, which of course
would not be suitable in general.  Nevertheless, this patch is a good =
test
that plgstrm, plmkstrm, plsfnam, plsdev, plcpstrm, and plreplot are all
implemented correctly in Fortran (77) to call the appropriate C library
routines with the appropriate arguments since I got identical results =
with
this patch to the equivalent C routine using the command-line option

"-save test_stream.ps"

Now a comment on the "special circumstances" referred to above.

If you run

./x01c -save test_stream.ps -dev <device>

with <device> set to either psc or xcairo you get the

*** PLPLOT WARNING ***
plreplot: plot buffer not available

warning referred to by German above.  However, if you specify the xwin =
or tk
devices you do produce a good plot in test_stream.ps.  I assume what is
going on is xwin and tk set up a plot buffer and the other devices do =
not.

Another issue for -dev xwin and -dev tk is that after they create a good
test_stream.ps file both the C and patched Fortran example 1 produces a
segfault.

German, obviously the current limitations of the plreplot capability are =
so
severe that it is not useful to your needs, but I thought I should make =
some
general comments about what is wrong in case some developers got moved =
to
deal with one of the following issues that came up from my =
investigation:

(1) Implement plmergeopts for fortran.

(2) plot buffer capability expanded to more devices

(3) Deal with the above segfault.

Alan
__________________________
Alan W. Irwin

Astronomical research affiliation with Department of Physics and =
Astronomy,
University of Victoria (astrowww.phys.uvic.ca).

Programming affiliations with the FreeEOS equation-of-state =
implementation
for stellar interiors (freeeos.sf.net); PLplot scientific plotting =
software
package (plplot.org); the libLASi project (unifont.org/lasi); the Loads =
of
Linux Links project (loll.sf.net); and the Linux Brochure Project
(lbproject.sf.net).
__________________________

Linux-powered Science
__________________________