gnuplot-beta

Feature question: waiting on a plot window

[Dima K. <gn...@di...>]

Hi.

I'm looking for a feature that (I think) doesn't exist currently. Want
to ask first, in case something DOES exist that I'm not seeing.

A number of applications that make plots use gnuplot as a backend. The
sequence you want there is:

1. User says "make a plot"

2. Application tells gnuplot to make a plot

3. gnuplot does its thing using an interactive terminal (x11, qt, wxt,
   ...) and a plot window pops up

4. user looks at the plot, then closes the window when they're done, and
   wants to continue using the application

The issue here is that currently the application (parent of the
"gnuplot" process) has no way of knowing when the user finished looking
at the plot, which necessitates ugly workarounds. For instance with
gnuplotlib I can write a script that just makes a plot. If I just call
gnuplotlib.plot(), then the application will make a plot and then exit
immediately. As a workaround I put a sleep(10000) after the plot() call.
I'd like to have some sort of gnuplotlib.wait() that blocks until
gnuplot is done. Maybe gnuplot can be asked to print something on the
console when the client window is closed, or something? Thoughts?

Re: Feature question: waiting on a plot window

[Ethan A M. <sf...@us...>]

On Friday, August 17, 2018 1:15:24 PM PDT Dima Kogan wrote:
> Hi.
> 
> I'm looking for a feature that (I think) doesn't exist currently. Want
> to ask first, in case something DOES exist that I'm not seeing.

This ought to be a FAQ or something.

The command you are looking for is
	pause mouse close

Recent discussion has indicated that on some systems in may also be
necessary add a bind command
	bind "Close" "exit gnuplot"
	pause mouse close

gnuplot will exit when the user closes the plot window.

If you want gnuplot to signal the parent application via some side channel
rather rather than exiting , that's a bit trickier.
There are several options but the details are OS dependent.
For example (not necessary the best option)

	bind "Close" "system('kill -SIGCONT $PARENTID')"

	Ethan

> A number of applications that make plots use gnuplot as a backend. The
> sequence you want there is:
> 
> 1. User says "make a plot"
> 
> 2. Application tells gnuplot to make a plot
> 
> 3. gnuplot does its thing using an interactive terminal (x11, qt, wxt,
>    ...) and a plot window pops up
> 
> 4. user looks at the plot, then closes the window when they're done, and
>    wants to continue using the application
> 
> The issue here is that currently the application (parent of the
> "gnuplot" process) has no way of knowing when the user finished looking
> at the plot, which necessitates ugly workarounds. For instance with
> gnuplotlib I can write a script that just makes a plot. If I just call
> gnuplotlib.plot(), then the application will make a plot and then exit
> immediately. As a workaround I put a sleep(10000) after the plot() call.
> I'd like to have some sort of gnuplotlib.wait() that blocks until
> gnuplot is done. Maybe gnuplot can be asked to print something on the
> console when the client window is closed, or something? Thoughts?

Re: Feature question: waiting on a plot window

[Daniel J S. <dan...@ie...>]

On 08/17/2018 03:15 PM, Dima Kogan wrote:
> Hi.
> 
> I'm looking for a feature that (I think) doesn't exist currently. Want
> to ask first, in case something DOES exist that I'm not seeing.
> 
> A number of applications that make plots use gnuplot as a backend. The
> sequence you want there is:
> 
> 1. User says "make a plot"
> 
> 2. Application tells gnuplot to make a plot
> 
> 3. gnuplot does its thing using an interactive terminal (x11, qt, wxt,
>     ...) and a plot window pops up
> 
> 4. user looks at the plot, then closes the window when they're done, and
>     wants to continue using the application
> 
> The issue here is that currently the application (parent of the
> "gnuplot" process) has no way of knowing when the user finished looking
> at the plot, which necessitates ugly workarounds. For instance with
> gnuplotlib I can write a script that just makes a plot. If I just call
> gnuplotlib.plot(), then the application will make a plot and then exit
> immediately. As a workaround I put a sleep(10000) after the plot() call.
> I'd like to have some sort of gnuplotlib.wait() that blocks until
> gnuplot is done. Maybe gnuplot can be asked to print something on the
> console when the client window is closed, or something? Thoughts?

Does "gnuplot --persist" work for your needs?  In the following, the 
gnuplot_qt process hangs around until the window is closed:

@linux ~ $ gnuplot --persist

	G N U P L O T
	Version 5.3 patchlevel 0    last modified 2018-04-26

	Copyright (C) 1986-1993, 1998, 2004, 2007-2018
	Thomas Williams, Colin Kelley and many others

	gnuplot home:     http://www.gnuplot.info
	mailing list:     gnu...@li...
	faq, bugs, etc:   type "help FAQ"
	immediate help:   type "help"  (plot window: hit 'h')

Terminal type is now 'qt'
Options are '0 font "Sans,9"'
gnuplot> system "ps -e | grep gnuplot"
  6680 pts/1    00:00:00 gnuplot
gnuplot> plot 1/x
gnuplot> system "ps -e | grep gnuplot"
  6680 pts/1    00:00:00 gnuplot
  6690 ?        00:00:00 gnuplot_qt
gnuplot> exit
@linux ~ $ ps -e | grep gnuplot
  6690 ?        00:00:00 gnuplot_qt
@linux ~ $ (manually close window)
manually: command not found
@linux ~ $ ps -e | grep gnuplot
@linux ~ $

Re: Feature question: waiting on a plot window

[Dima K. <gn...@di...>]

Ethan A Merritt <sf...@us...> writes:

> On Friday, August 17, 2018 1:15:24 PM PDT Dima Kogan wrote:
>>
>> I'm looking for a feature that (I think) doesn't exist currently. Want
>> to ask first, in case something DOES exist that I'm not seeing.
>
> The command you are looking for is
> 	pause mouse close
>
> Recent discussion has indicated that on some systems in may also be
> necessary add a bind command
> 	bind "Close" "exit gnuplot"
> 	pause mouse close
>
> gnuplot will exit when the user closes the plot window.
>
> If you want gnuplot to signal the parent application via some side channel
> rather rather than exiting , that's a bit trickier.
> There are several options but the details are OS dependent.
> For example (not necessary the best option)
>
> 	bind "Close" "system('kill -SIGCONT $PARENTID')"

Ooh, that looks like what I want. Thanks! Will try it out at some point.
Daniel: --persist isn't quite what I want. I'd like gnuplot to stay
alive, and to tell me when the client window has gone away.

For the record, it's for this: https://github.com/dkogan/gnuplotlib

Re: Feature question: waiting on a plot window

[Dima K. <gn...@di...>]

Dima Kogan <gn...@di...> writes:

> Ethan A Merritt <sf...@us...> writes:
>
>> On Friday, August 17, 2018 1:15:24 PM PDT Dima Kogan wrote:
>>>
>>> I'm looking for a feature that (I think) doesn't exist currently. Want
>>> to ask first, in case something DOES exist that I'm not seeing.
>>
>> The command you are looking for is
>> 	pause mouse close

This works in its most basic form, which is awesome. Thanks! But I'm now
going to be a pain in the butt. For a gnuplot-using application to work
reasonably, this needs to only wait for a window-close event when one is
coming: i.e. when a window is open. Scenarios that could happen:

1. User already closed the window before I send my "pause mouse close"

2. We're using a non-interactive terminal (dumb, pdf, etc etc)

Ideas on handling that?

Re: Feature question: waiting on a plot window

[sfeam <sf...@us...>]

On Sunday, 19 August 2018 20:25:24 Dima Kogan wrote:
> Dima Kogan <gn...@di...> writes:
> 
> > Ethan A Merritt <sf...@us...> writes:
> >
> >> On Friday, August 17, 2018 1:15:24 PM PDT Dima Kogan wrote:
> >>>
> >>> I'm looking for a feature that (I think) doesn't exist currently. Want
> >>> to ask first, in case something DOES exist that I'm not seeing.
> >>
> >> The command you are looking for is
> >> 	pause mouse close
> 
> This works in its most basic form, which is awesome. Thanks! But I'm now
> going to be a pain in the butt. For a gnuplot-using application to work
> reasonably, this needs to only wait for a window-close event when one is
> coming: i.e. when a window is open. Scenarios that could happen:
> 
> 1. User already closed the window before I send my "pause mouse close"

That sounds like a case of "well then don't do that".
If the parent program sends the plot command and the pause command
in immediate succession the time window in which that race could happen
would be very small.  If the commands do not come in immediate
succession then maybe the program logic needs re-thinking.
Can you give a more complete example of the flow of events?

> 2. We're using a non-interactive terminal (dumb, pdf, etc etc)
> Ideas on handling that?

So far as I know, in that case the next <\n> in the input stream
will terminal the "pause" command.  Does that not work for you?

	Ethan

Re: Feature question: waiting on a plot window

[Dima K. <gn...@di...>]

sfeam <sf...@us...> writes:

> On Sunday, 19 August 2018 20:25:24 Dima Kogan wrote:
>> Dima Kogan <gn...@di...> writes:
>>
>> > Ethan A Merritt <sf...@us...> writes:
>> >
>> >> On Friday, August 17, 2018 1:15:24 PM PDT Dima Kogan wrote:
>> >>>
>> >>> I'm looking for a feature that (I think) doesn't exist currently. Want
>> >>> to ask first, in case something DOES exist that I'm not seeing.
>> >>
>> >> The command you are looking for is
>> >> 	pause mouse close
>>
>> This works in its most basic form, which is awesome. Thanks! But I'm now
>> going to be a pain in the butt. For a gnuplot-using application to work
>> reasonably, this needs to only wait for a window-close event when one is
>> coming: i.e. when a window is open. Scenarios that could happen:
>>
>> 1. User already closed the window before I send my "pause mouse close"
>
> That sounds like a case of "well then don't do that".
> If the parent program sends the plot command and the pause command
> in immediate succession the time window in which that race could happen
> would be very small.  If the commands do not come in immediate
> succession then maybe the program logic needs re-thinking.
> Can you give a more complete example of the flow of events?
>
>> 2. We're using a non-interactive terminal (dumb, pdf, etc etc)
>> Ideas on handling that?
>
> So far as I know, in that case the next <\n> in the input stream
> will terminal the "pause" command.  Does that not work for you?

I played with it a bit more just now, and it's good-enough. It would be
NICE if "pause mouse close" could know if there's anything to
potentially wait for, but I guess I don't strictly need it.

Thanks much. This will fix a long-standing annoyance with gnuplotlib

Re: Feature question: waiting on a plot window

[sfeam <sf...@us...>]

On Sunday, 19 August 2018 23:52:05 Dima Kogan wrote:
> sfeam <sf...@us...> writes:
> 
> > On Sunday, 19 August 2018 20:25:24 Dima Kogan wrote:
> >> Dima Kogan <gn...@di...> writes:
> >>
> >> > Ethan A Merritt <sf...@us...> writes:
> >> >
> >> >> On Friday, August 17, 2018 1:15:24 PM PDT Dima Kogan wrote:
> >> >>>
> >> >>> I'm looking for a feature that (I think) doesn't exist currently. Want
> >> >>> to ask first, in case something DOES exist that I'm not seeing.
> >> >>
> >> >> The command you are looking for is
> >> >> 	pause mouse close
> >>
> >> This works in its most basic form, which is awesome. Thanks! But I'm now
> >> going to be a pain in the butt. For a gnuplot-using application to work
> >> reasonably, this needs to only wait for a window-close event when one is
> >> coming: i.e. when a window is open. Scenarios that could happen:
> >>
> >> 1. User already closed the window before I send my "pause mouse close"
> >
> > That sounds like a case of "well then don't do that".
> > If the parent program sends the plot command and the pause command
> > in immediate succession the time window in which that race could happen
> > would be very small.  If the commands do not come in immediate
> > succession then maybe the program logic needs re-thinking.
> > Can you give a more complete example of the flow of events?
> >
> >> 2. We're using a non-interactive terminal (dumb, pdf, etc etc)
> >> Ideas on handling that?
> >
> > So far as I know, in that case the next <\n> in the input stream
> > will terminal the "pause" command.  Does that not work for you?
> 
> I played with it a bit more just now, and it's good-enough. It would be
> NICE if "pause mouse close" could know if there's anything to
> potentially wait for, but I guess I don't strictly need it.

If you have identified a sequence of reasonable events that causes gnuplot
to lock up entirely, I would consider that a bug.  In the case of 
"pause mouse" I agree that if you issue this command in the state that
the current terminal is mouseable but the most recent plot window has
been closed then you have a potential lock-up.  

I say "potential" because from a normal terminal session you can break the
lock by typing Ctrl-C.  This resets error and pause conditions and returns
you to the gnuplot command line.   

However, if gnuplot is being run from some non-terminal controlling process
I am not entirely clear on who would have to send SIGINT (Ctrl-C) to whom.
I don't understand you usage scenario well enough to guess.
Does the user who is operating the mouse also have a terminal window open?
If Ctrl-C is typed in that window, what process receives the signal?

	Ethan
  

> Thanks much. This will fix a long-standing annoyance with gnuplotlib