missing pdf terminal; was --> [changeset] print.m (matlab compatibility)

[Ben Abbott]

On Mar 13, 2009, at 3:41 PM, John W. Eaton wrote:

> On 13-Mar-2009, Ben Abbott wrote:
>
> | On Mar 13, 2009, at 2:43 PM, John W. Eaton wrote:
> |
> | > On 13-Mar-2009, Ben Abbott wrote:
> | >
> | > | I don' t think it matters either way.  __gnuplot_get_var__  
> uses the
> | > | stream stored in the figure's "__plot_stream__" which is  
> opened by
> | > | popen2.
> | >
> | > If there is only one stream (i.e., we are using popen instead of
> | > popen2), then the communication can only be one way (from Octave  
> to
> | > gnuplot).  So in that case how would you get the information  
> back from
> | > gnuplot without a FIFO file to use as a separate communication
> | > channel?
> | >
> | > jwe
> |
> |
> | The reason is that the figure property __plot_stream__ is opened  
> using
> | popen2, and must exist (I think, so correct me if I'm wrong) when  
> the
> | popen plot stream used for printing is opened.
> |
> | To verify my understanding, I added the lines below (42-44) to
> | gnuplot_drawnow.m
> |
> |   30 function gnuplot_drawnow (h, term, file, mono, debug_file)
> |   31
> |   32   if (nargin < 4)
> |   33     mono = false;
> |   34   endif
> |   35
> |   36   if (nargin >= 3 && nargin <= 5)
> |   37     ## Produce various output formats, or redirect gnuplot  
> stream
> | to a
> |   38     ## debug file.
> |   39     plot_stream = [];
> |   40     fid = [];
> |   41     printing = ! output_to_screen (gnuplot_trim_term (term));
> |   42     if (printing)
> |   43       get (h, "__plot_stream__")
> |   44     endif
> |
> | Typing the following at the prompt results in
> |
> | 	close all;
> | 	drawnow
> | 	figure (1); print (gcf, "-dpng", "test.png")
> | ans =
> |
> |     4   5
> |
> | In addiition, by adding line 111 to gnuplot_drawnow
> | (open_gnuplot_stream), it appears to me that the popen2 stream for  
> the
> | display must be open prior to the popen stream used for printing.
> |
> |   95 function plot_stream = open_gnuplot_stream (npipes, h)
> |   96   cmd = gnuplot_binary ();
> |   97   if (npipes > 1)
> |   98     [plot_stream(1), plot_stream(2), pid] = popen2 (cmd);
> |   99     if (pid < 0)
> | 100       error ("drawnow: failed to open connection to gnuplot");
> | 101     endif
> | 102   else
> | 103     plot_stream = popen (cmd, "w");
> | 104     if (plot_stream < 0)
> | 105       error ("drawnow: failed to open connection to gnuplot");
> | 106     endif
> | 107   endif
> | 108   if (! isempty (h))
> | 109     set (h, "__plot_stream__", plot_stream);
> | 110   endif
> | 111   fprintf ("plot_stream = "); disp (plot_stream)
> | 112 endfunction
> |
> | octave:49> close all
> | octave:50> drawnow
> | octave:51> figure (1); print (gcf, "-dpng", "test.png")
> | plot_stream =    4   5
> | ans =
> |
> |     4   5
> |
> | plot_stream =  6
> |
> | I have no idea why popen is used instead of popen2.
>
> I think the idea was to avoid using popen2 unless it was actually
> needed.
>
> | In any event, is this not working as it is supposed to? ...  
> meaning is
> | it supposed to be possible to open a plot stream for printing and
> | avoid opening one for the display?
>
> Yes.  What does
>
>  figure (1, 'visible', 'off');
>  plot (...);
>  print ....
>
> do?

Ok, that is a problem.

octave:62> close all
octave:63> figure (1); axes (); set (gcf, "visible", "off"); print  
(gcf, "-dpng", "test.png")
ans = [](0x0)
plot_stream =  4

How to proceed?

Shall the  check that the device/terminal availability only be made  
when numel(__plot_stream__) == 2?

or, should we just use popen2 in all cases, and add the terminal check  
immediately after opening it?

Ben