Re: [Matplotlib-users] advice on writing an application

[Matt N. <new...@ca...>]

Dear Massimo,

Sorry I wasn't able to respond sooner.  I've been running experiments
all day.  As a warning, this response may be long, and I won't take
the time to be overly polite.  So let me say it now: Matplotlib is a
great plotting library and John should be knighted.

I was in a similar dilemma a little over a year ago when I was
comfortable enough with matplotlib and its development that I knew it
was what I wanted to commit to using.  At that time (late summer
2004), wxmpl did not exist and many of the additions for interactivity
in matplotlib did not exist.  I had already decided to abandon
Tkinter/Pmw.BLT plotting, but it took awhile to find a better
solution. Matplotlib is it.

And I definitely wanted (and still want) a wxPython plotting widget
which is intended to go into applications.  Much of matplotlib, and
the other responses seem to fail to understand this: I (and I'm
assuming you) want a plotting widget that goes into a wxPython
application.  I want to say something not much harder than
      plotpanel =3D SomeMatplotLibPanel(wx_parent_id)
      plotplanel.plot(x,y)

And then have the user (that is *MY* user -- the person running the
program, not the person writing the script)  be able to change the
color, change the titles, zoom in, zoom out, print, save to a PNG.

MPlot tries to do this.  For 2-d line plots, it does this fairly well.
 It may not be the best code, it certainly could use improvement.=20
Please feel free to make or suggest changes.  If you (or anyone else)
would like to use it or develop it, please let me know how I can help
you.  I'd love for it to be improved -- it really needs false color
maps soon.  OTOH, if something better comes along, I'll happily use
it.

Pylab is NOT suitable for applications.  It assumes that the end user
is someone who uses python.  Somehow this became the higher priority
for matplotlib.  I think this is a terrible mistake.  Seeing so many
examples and questions on this mailing list assuming
    from pylab import *

is really quite sad.  To me it suggest this lovely packaged advertised
as a library is not being used as a library at all. Matplotlib is far
too nice to be an add-on to IPython or used only for writing
quick-n-dirty scripts.

wxMPL is definitely a very nice wx wrapping of MPL.  My recollection
is that Ken McIvor wrote wxmpl after I showed him MPlot, but I'd defer
to Ken's version of the story.  I'm also very happy that Ken's
maintaining the wx backend.  I definitely spent most of the effort in
MPlot on bindings, printing, user configuration, and worrying about
being able to 'stripchart'  (update a trace at close to 'real time').=20
I'm sure that some of what I wrote could be replaced with wxmpl or
matplotlib calls at this point.  You may understand my reluctance to
do this (like it works and I have my own data to analyze and
applications to write), but I would not be opposed to seeing this
done.

I would also characterize wxMPL as being focused on the
programmer/script writer, not on the end user of an application.  So
it's not exactly a 'wxPython Plot Widget'.  But it might make the code
of MPlot easier to use/manage/improve.

On using matplotlib bindings and the Navigator toolbars, I'd guess you
don't want to do this.  The toolbars are ugly, take up screen real
estate, do stuff you don't need and don't do stuff you do need.  I'm
sure these are fine when you're doing a quick-n-dirty plot with an
'ipython -pylab' script, but I somehow never need to do that.  Using
the matplotlib bindings would mean separate kinds of event handlers
for a MPL Panel and a non-MPL Panels.  I guess that's inevitable, but
I'd still suggest sticking with straight wx.Bind methods. I don't
think the MPL bindings provide anything that can't easily be
reproduced, though it's been awhile since I looked at them.

Since you're short on time (we all are), I suggest giving MPlot a spin
and see if it does enough of what you need.  I'd appreciate hearing
what does and doesn't.    Finally, I was very happy to see your
response to the fairly silly 'use some other package', and agree
completely with your sentiment.

Cheers,

--Matt

PS: a very short wxPython / MPlot example:

import wx
import MPlot
import matplotlib.numerix as Num

x   =3D Numpy.arange(0.0,10.0,0.1)
y   =3D Numpy.sin(2*x)/(x+2)
app =3D wx.PySimpleApp()

pframe =3D MPlot.PlotFrame()
pframe.plot(x,y)
pframe.set_title('Test Plot')
pframe.set_xlabel(r'$R  (\angstrom)$')
pframe.write_message('MPlot PlotFrame example: Try Help->Quick Reference')
pframe.Show()
pframe.Raise()
app.MainLoop()