On Wed Feb 18 2015 at 5:37:52 AM Ben Abbott <
address@hidden> wrote:
> On Feb 18, 2015, at 12:14 AM, Alex K <address@hidden> wrote:
>
> On Fri Feb 13 2015 at 1:53:40 PM Ben Abbott <address@hidden> wrote:
>
>> On Feb 13, 2015, at 9:14 AM, Ben Abbott <address@hidden> wrote:
>>
>>> On Feb 13, 2015, at 2:26 AM, Alex K <address@hidden> wrote:
>>>
>>> On Wed Feb 11 2015 at 4:36:55 PM Ben Abbott <address@hidden> wrote:
>>> > On Feb 11, 2015, at 1:39 PM, Alex K <address@hidden> wrote:
>>> >
>>> > Hi!
>>> >
>>> > Is it possible to run a custom function every time any plot is changed? For example, when running `plot`, `axis` etc., if they modify a figure on the screen I would like to detect that and save it to a new file.
>>> >
>>> > I use gnuplot as backend, so any solution involving configuring gnuplot will also work for me.
>>> >
>>> > Thanks!
>>> > Alex
>>>
>>> If you can provide mode details, someone may have a more efficient solution … but for a general solution I’d add a listener to the figures “children” property.
>>>
>>> See “help addlistener” to see how to do that.
>>>
>>> Ben
>>>
>>> Hi Ben,
>>>
>>> Thanks for the reply! For more context, I'm trying to make octave auto-save plots to files on the disk every time they are updated. I've tried addlistener but it doesn't seem to work:
>>>
>>> function my_handler
>>> fprintf ("my_handler called\n");
>>> endfunction
>>> addlistener (gcf, "children", address@hidden, "my string"})
>>> sombrero
>>>
>>> the handler is not getting called.
>>>
>>> Best,
>>> Alex
>>
>> Ok, that’s embarrassing. I get no error, and it doesn’t work for me either.
>>
>> There are many examples of this working correctly in Octave’s sources. (take a look at the m-file code of plotyy or subplot for examples).
>>
>> Does anyone see a problem with Alex’s example?
>>
>> Ben
>
> I filed a bug report.
>
> https://savannah.gnu.org/bugs/index.php?44242
>
> Ben
>
> I guess I found the a way to get notification when the plot changes - it has a "__modified__" property that I can add listener to. However, if I call "print" from the handler, it doesn't work, giving a strange Ghostscript error. Any ideas?
>
> Code:
>
> function my_handler(h, dummy)
> if (strcmp(get(h, "__modified__"), "off"))
> disp 'saving snapshot...';
> print(gcf, 'snapshot.png', '-debug', '-dpng', '-S640,480')
> endif
> endfunction
>
> addlistener (gcf, "__modified__", @my_handler);
>
> Error message:
>
> plot(sin(-10:0.1:10))
> saving snapshot...
> Ghostscript command: '/usr/bin/gs -dQUIET -dNOPAUSE -dBATCH -dSAFER -sDEVICE=png16m -dTextAlphaBits=4 -dGraphicsAlphaBits=4 -r72x72 -dEPSCrop -sOutputFile="snapshot.png" /tmp/oct-eyO49W.eps'
> gnuplot-pipeline: '/usr/bin/gs -dQUIET -dNOPAUSE -dBATCH -dSAFER -sDEVICE=png16m -dTextAlphaBits=4 -dGraphicsAlphaBits=4 -r72x72 -dEPSCrop -sOutputFile="snapshot.png" /tmp/oct-eyO49W.eps ; rm /tmp/oct-eyO49W.eps'
> GPL Ghostscript 9.10: Unrecoverable error, exit code 1
> rm: cannot remove '/tmp/oct-eyO49W.eps': No such file or directory
> ---------- output begin ----------
> Error: /undefinedfilename in (/tmp/oct-eyO49W.eps)
> Operand stack:
>
> Execution stack:
> %interp_exit .runexec2 --nostringval-- --nostringval-- --nostringval-- 2 %stopped_push --nostringval-- --nostringval-- --nostringval-- false 1 %stopped_push
> Dictionary stack:
> --dict:1178/1684(ro)(G)-- --dict:0/20(G)-- --dict:77/200(L)--
> Current allocation mode is local
> Last OS error: No such file or directory
>
> ----------- output end -----------
> error: print: failed to print
> error: called from:
> error: /usr/share/octave/3.8.1/m/plot/util/private/__gnuplot_print__.m at line 165, column 7
> error: /usr/share/octave/3.8.1/m/plot/util/print.m at line 423, column 14
> error: my_handler at line 15, column 5
>
> Thanks!
> Alex
Try adding a "drawnow ()" to the handler before the print command.
Ben