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

[Ben Abbott]

On Mar 13, 2009, at 3:58 PM, Ben Abbott wrote:

>
> 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

John/others,

Does this work for you?

If your gnuplot was built without pdf support, the line below should  
throw an error.

	close all; figure (1); axes (); print (gcf, "-dpdf", "test.pdf")

But this one should work

	close all; figure (1); axes (); print (gcf, "-dpng", "test.png")

and the one below should produce the png without displaying the figure.

	close all; figure (1, "visible", "off"); axes (); print (gcf, "- 
dpng", "test.png")

Ben

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