Matplotlib graph autoscale

Hello everyone,

I've adapted a python code to plot real time data but I don't manage
to have an auto-scale on my graph. I don't understand because I use"
set_autoscale_on(True)"

Do you have an idea?

Here is "my" simplified code:

#!/usr/bin/env python

#from visa import *
from pylab import *

# for command-line arguments
import sys

# Python Qt4 bindings for GUI objects
from PyQt4 import QtGui

# Numpy functions for image creation
import numpy as np

# Matplotlib Figure object
from matplotlib.figure import Figure
# import the Qt4Agg FigureCanvas object, that binds Figure to
# Qt4Agg backend. It also inherits from QWidget
from matplotlib.backends.backend_qt4agg import FigureCanvasQTAgg as FigureCanvas
# import the NavigationToolbar Qt4Agg widget
from matplotlib.backends.backend_qt4agg import NavigationToolbar2QTAgg
as NavigationToolbar

···

###########################################################################################
###########################################################################################

class CPUMonitor(FigureCanvas):
    """Matplotlib Figure widget to display CPU utilization"""
    def __init__(self,parent):

        # first image setup
        self.fig = Figure()
        self.ax = self.fig.add_subplot(111)
# self.fig.apply__adjustable()
#

        # initialization of the canvas
        FigureCanvas.__init__(self, self.fig)

        # set specific limits for X and Y axes
        #self.ax.set_xlim(0, 2)
        #self.ax.set_ylim(0, 1.5)

        # and disable figure-wide autoscale
        self.ax.set_autoscale_on(True)
        #self.ax.set_adjustable('datalim')

        # generates first "empty" plots
        self.user, self.nice = [], []

        self.l_user, = self.ax.plot([], self.user, label='Voltage')
        self.l_nice, = self.ax.plot([], self.nice, label='Voltage2')

        # add legend to plot
        self.ax.legend()

        # force a redraw of the Figure
        #self.fig.canvas.draw()

        # initialize the iteration counter
        #self.cnt = 0

        # call the update method (to speed-up visualization)
        self.timerEvent(None)

        # start the timer, to trigger an event every x milliseconds)
        self.timer = self.startTimer(100)

    def get_info(self):

# my_instrument1 = instrument("GPIB0::24", term_chars = CR)
# my_instrument1.write("DCV ")
# my_instrument1.write("TRIG AUTO")
# mesure1 = my_instrument1.read_values()
          
        fichier = open("fichier.dat", "a")
        fichier.write(str(1)+"\t")
        fichier.close()

        fichier = open("fichier.dat", "a")
        fichier.write(str(1)+"\t")
        fichier.close()

        return [0.8]
  
    def get_info2(self):
  
# my_instrument2 = instrument("GPIB0::??", term_chars = CR)
# my_instrument2.write("DCV ")
# my_instrument2.write("TRIG AUTO")
# mesure2 = my_instrument2.read_values()
#
        fichier = open("fichier.dat", "a")
        fichier.write(str(2)+"\n")
        fichier.close()

        return [0.9]

    def timerEvent(self, evt):
        """Custom timerEvent code, called upon timer event receive"""
        # get the value from the device

        result1 = self.get_info()
        result2 = self.get_info2()

        # append new data to the datasets
        self.user.append(result1)
        self.nice.append(result2)
  
        # update lines data using the lists with new data
        self.l_user.set_data(range(len(self.user)), self.user)
        self.l_nice.set_data(range(len(self.nice)), self.nice)
  
        # force a redraw of the Figure
        self.fig.canvas.draw()
        FigureCanvas.updateGeometry(self)

class ApplicationWindow(QtGui.QMainWindow):
    """Example main window"""
    def __init__(self):
        # initialization of Qt MainWindow widget
        QtGui.QMainWindow.__init__(self)
        # set window title
        self.setWindowTitle("QHE manip")

        # instantiate a widget, it will be the main one
        self.main_widget = QtGui.QWidget(self)

        # create a vertical box layout widget
        vbl = QtGui.QVBoxLayout(self.main_widget)
        # instantiate our Matplotlib canvas widget
        qmc = CPUMonitor(self.main_widget)
        # instantiate the navigation toolbar
        ntb = NavigationToolbar(qmc, self.main_widget)
        # pack these widget into the vertical box
        vbl.addWidget(qmc)
        vbl.addWidget(ntb)

        # set the focus on the main widget
        self.main_widget.setFocus()
        # set the central widget of MainWindow to main_widget
        self.setCentralWidget(self.main_widget)

# create the GUI application
qApp = QtGui.QApplication(sys.argv)
# instantiate the ApplicationWindow widget
aw = ApplicationWindow()
# show the widget
aw.show()
# start the Qt main loop execution, exiting from this script
# with the same return code of Qt application
sys.exit(qApp.exec_())