Re: [Matplotlib-users] subplots and forked show()

[John H. <jdh...@ac...>]

>>>>> "Mark" == Mark Engelhardt <ma...@st...> writes:

    Mark> Hi, I am not in interactive mode, I am writing scripts that
    Mark> handle a bunch of data and then plot it all.  However, when
    Mark> show() is called, the script stops and waits for all the
    Mark> windows it opens to be closed before continuing.  What I was
    Mark> hoping for was a way to have the plots be drawn in windows
    Mark> that were no longer hooked into the script, such that the
    Mark> script could continue running (to completion) regardless of
    Mark> what happened to the open windows.  I did try 'draw()',
    Mark> which does not appear to open any new windows.

Hi Mark, 

Thanks for the explanation.  Now I understand what you are trying to
do.  You are right about draw, all it does is redraw an existing
figure, eg if you have changed some data in it.

You have to get a little bit into the GTK API / event handling
mechanism to do this right.  One way is to use the full blown gtk API
with matplotlib, as in examples/embedding_in_gtk*.py.

The easier way is to just use as much of the API as you need, and take
over the function of the backend 'show' function.  You'll be doing an
end run around the matplotlib.matlab figure manager, which means some
of these won't work (like gcf, close, etc.).  That's OK, because you
won't be using the matplotlib.matlab interface.  Do not import
matplotlib.matlab with this approach as the result is undefined!

There are a few things you need to do

  * Define function(s) / class(es) which create your figures

  * Define a main function which call these functions as necessary.
    Return False from this function

  * Add main to the gtk idle handler.  Returning False in 'main' will
    cause this function to be called only once.

  * Start the gtk mainloop yourself.  After gtk is started, your
    'main' function will be called and you're off to the races.

  * If there is something you want from matplotlib.matlab, say the
    'axis' command, just look at the src code to see how axis is
    implemented with the matplotlib API and make those calls yourself.

You may want to spend some time with the pygtk class reference at
http://www.pygtk.org/pygtk2reference/gtk-class-reference.html and the
matplotlib class reference at
http://matplotlib.sourceforge.net/classdocs.html.  In the example
below

  * canvas inherits from gtk.DrawingArea and
    backends.FigureCanvasGTK (which in turn derives from 
    backend_bases.FigureCanvasBase)

  * manager is a backends.backend_gtk.FigureManagerGTK
    which inherits from backend_bases.FigureManagerBase

  * manager.window is a gtk.Window() (you can also hide or close this
    window with pygtk API calls)

  * ax is a axes.Subplot which inherits from axes.Axes


Here is an example

#!/usr/bin/env python
import matplotlib
matplotlib.use('GTKAgg')
from matplotlib.backends.backend_gtkagg import new_figure_manager
from matplotlib.numerix import *
import gtk

def main(*args):

    manager1 = new_figure_manager(1)
    canvas1 = manager1.canvas
    fig1 = canvas1.figure
    ax1 = fig1.add_subplot(111)
    ax1.plot([1,2,3])
    manager1.window.show()  # non blocking

    manager2 = new_figure_manager(2)
    canvas2 = manager2.canvas
    fig2 = canvas2.figure
    ax2 = fig2.add_subplot(111)
    ax2.plot([6,5,4])
    manager2.window.show()
    return False

gtk.idle_add(main)
gtk.mainloop()