Re: [Bug-plotutils] legend feature for graph, etc.

[Daniel Llorens]

Hello Rob,

I didn't see this mail since I am not subscribed to the list. I should have 
followed up, I'm sorry. I'm reading it now because I've added the nan/inf 
feature to graph and that made me check the list again.

> I share your interest in getting things moving again, with
> plotutils.  My own interest is primarily in libplot/libplotter,
> and in low-level drawing primitives.  I always intended `graph'
> to be a sample application based on libplot, and hoped that other
> people would write additional ones.

Right, my main interest is as a graph user.

However, I think that having a public repository would be very useful. It would 
be possible to have all the various patchsets available in a single place, what 
the current state of development is, etc. And GNU provides this service, with 
Savannah.

> Would you be interested in turning graph into a library?

I think so, such a library would be useful to me. But I really can't promise 
that I have the ability to do the work in the little time I could devote to it 
:-/

> > Multiline titles and labels.
> 
> This would be rather easy to add to graph (it would be
> less ambitious than turning it into a library).

I've been doing this with a hack involving subscripts and superscripts. Only 
works reasonably for two lines, but then I didn't need more. The hack is 
'\mk\spFirst line\ep\rt\sb\Second line\eb' in case it is useful to somebody.

> > Reading NaNs and Infs in data files.
> 
> This feature would be very easy to add to graph.

Right. I've done this in https://gitorious.org/legend-patch-for-gnu-graph (last 
two patches, 66a47e2 and dc6eff8). The changes are two:

* I require C99, where scanf is able to read inf and nan on its own. This also 
enables exp format to be read (before, only fixed point format was accepted).

* I fix the clip_line routines in plotter.c and misc.c to clip correctly the 
infinities, and I skip points with nan values in reader.c.

> These would really be enhancements to libplot, on which graph
> is based.  (Adding Unicode support to libplot would be a lot of work,
> if it were implemented consistently across all output formats.)
> Could you tell me more about your need for Unicode, and
> especially about the issue of transparency and pdf's?

The need for unicode is to add math symbols or greek in the labels, the titles, 
etc. I think nowadays it's an expected feature for anything that handles text, 
but I absolutely understand that it can be a lot of work. The escape sequences 
do work for what I need, but it's not ideal to have to refer to special escape 
sequences that in practice I need for this one program and nothing else.

I'd like to have transparency for figures with very many lines, or for filled 
regions, to be able to see the overlaps.

Regards

        Daniel