Re: pasting code into gnuplot

[Ethan M. <merritt@u.washington.edu>]

On Wednesday 07 January 2004 01:07, arn...@we... wrote:
>
> Yes this is really nasty (sorry for bringing it up again ;-) -
> anyway, I am just wondering if there is any chance at all that
> this can be made to work in a reliable way?

I do not think it is possible so long as the terminal and
X11 input streams are intermingled.

> Are there any reasonable alternatives?

Yes, but it would be a major, major change to the existing layout.
So it won't happen any time soon.

> Alright, then I tried to re-compile with
> ./configure --disable-mouse
> Here the compile ended with
>
> In file included from term.h:267,
>                  from term.c:1043:
> ../term/x11.trm:304: error: `X11_MOUSE_FEEDBACK' undeclared (first use
> in this function)

I'll fix that immediately.

>       So all this feedback and mousing stuff seems problematic
>       when sending commands to gnuplot via a pipe...

This is a known problem, but none of us fully understand it.
It seems to depend on the environment from which the pipe
is opened.  For me, it works from C and from octave but fails from awk.
It seems to work from perl also, but my perl scripts are not
normally being run interactively so I'm not sure I would have
seen the failure in practice.

In the case of awk scripts, the problem can be ameliorated by
commenting out the call to setvbuf() in x11.trm as in the=20
following patch:

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
--- gnuplot/term/x11.trm        2003-09-30 13:14:43.000000000 -0700
+++ gnuplot-cvs/term/x11.trm    2003-10-20 17:26:10.000000000 -0700
@@ -599,12 +607,14 @@
            ipc_back_fd =3D fdes_back[0];
            close(fdes_back[1]);        /* the parent doesn't need this *=
/
=20
+#ifdef BROKEN /* EAM Oct 2003 - This has broken awk+gnuplot */
            /* apparently multi-character inputs like escape sequences
             * but also mouse-pasted text got buffered and therefore
             * didn't trigger the select() function in X11_waitforinput()=
=2E
             * Switching to unbuffered input solved this (although I don'=
t
             * really like this solution 23 Jan 2002 (joze) */
            setvbuf(stdin, (char *) 0, _IONBF, 0);
+#endif=20
        } else {
            /* we do not open a bidirectional communication
             * for non-tty's by default. If this is desired,
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

You may find that the same is true for your python environment.

I say "ameliorated" rather than "fixed" because if you apply this
patch then other peculiarities result - the main one being that
"pause -1" behaves unreliably.=20

>   2.) I'd really love to have mousing working, even when gnuplot
>       is steered via a pipe.
>       Example:
>          - do a plot (in my case from python)
>          - send a "pause mouse" command
>          - read MOUSE_X and MOUSE_Y back to the calling program

For that you need the full-blown feedback loop, not just  --enable-mouse
I did get this working nicely from C code, so the basic idea is
sound.  The problem comes from some difference in the scripting
environment.  I wish I knew exactly what.

>       See http://www.physik.tu-dresden.de/~baecker/python/plot.html
>       for a brief example on how to get variables from gnuplot
>       back to python.

You may find that removing the call to setvbuf() makes your
python example work.  Please let us know.

--=20
Ethan A Merritt       merritt@u.washington.edu
Biomolecular Structure Center Box 357742
University of Washington, Seattle, WA 98195