[Texmacs-dev] inline plots

[Bill Eaton]

I've already posted this to the Users mailing list. Someone suggested I
cross post here. 

I'd like to solicit suggestions on how to do inline plots in various 
sessions. I've already figured out how to do it in one session and it 
doesn't look impossible for others.

I know this is topic comes up often, but I have found few solutions. If 
you want to have a live mathematical scratchpad or notebook, its 
desirable to have live inline figures. If you're using the Maxima, 
Python,  Octave, etc. plugin, you could invoke an extra command to 
insert an inline plot.

In fact, this is already possible in the Python plugin, via the ps_out 
function. This ps_out function points the way how we might do it in 
other environments.  Heck, maybe it's already possible in other 
environments but I just don't know how. In Python, here's a minimal example:
    import matplotlib
    matplotlib.use('ps')
    from pylab import *
    fig = figure(figsize=(3,2))
    ax=fig.add_subplot(111)
    ax.plot([1,2,3])
    ax.set_title('inline demo')
    savefig('demo.eps')
    ps_out('demo.eps')
So from the session, you save an EPS file and then invoke the ps_out 
function to display it. The displayed plot behaves pretty well. You can 
go back and change things, overwrite the EPS figure and then reinvoke 
ps_out and you get a new plot. Pure magic.

I looked inside ps_out and it just spits out the EPS file plus some 
extra stuff (here i use + for string concatenation:
    chr(2)+'ps:'+<EPS file contents>+chr(5)

It should be easy to do the same thing in Octave. The ps_out function in 
Octave could be:
     function ps_out(fname)
        disp( [char(2); 'ps:';  fileread(fname) ; char(5)] )
     endfunction

I'm dying to test this out and add more sophisticated error checking, 
but I don't know how to hack the appropriate file to look for the ps_out 
function. I think it would be in tmrepl.m. If someone can suggest the 
appropriate lines to modify, I would greatly appreciate and be happy to 
report my findings.

Likewise, it would be really swell to have a similar functionality in 
Maxima. There I have less of a clue, but I'm guessing the 
texmacs-maxima-<ver>.lisp file is the one to hack. I'm willing to do 
some legwork if anyone has suggestions.

--Bill Eaton