title: Python matplotlib Update figure after savefig called
body: <p>My problem is:
  I have Matplotlib figure in PyGTK application, that is constatly updated each few seconds. I've added abbility to save figure to disk as PNG file. After calling <code>figure.savefig(filename, other parameters)</code> my figure in application stops being updated.</p>
  
  <p>Figure initialization phase:</p>
  
  <pre><code># setup matplotlib stuff on empty space in vbox4
      figure = Figure()
      canvas = FigureCanvasGTK(figure) # a gtk.DrawingArea
      canvas.show()
      self.win.get_widget('vbox4').pack_start(canvas, True, True) # this will be aded to last place
      self.win.get_widget('vbox4').reorder_child(canvas, 1) #place plot to space where it should be
  </code></pre>
  
  <p>Figure is being updated this way (this called each few seconds in separate thread):</p>
  
  <pre><code>def _updateGraph(self, fig, x, x1, y):
      #Various calculations done here
  
      fig.clf()#repaint plot: delete current and formate a new one
      axis = fig.add_subplot(111)
      #axis.set_axis_off()
      axis.grid(True)
  #remove ticks and labels
      axis.get_xaxis().set_ticks_position("none")
      for i in range(len(axis.get_xticklabels())): axis.get_xticklabels()[i].set_visible(False)
      axis.get_yaxis().set_ticks_position("none")
      axis.plot(numpy.array(x),numpy.array(y)/(1.0**1), "k-" ,alpha=.2)
      axis.set_title('myTitle')
      fig.autofmt_xdate()
      fig.canvas.draw()
  </code></pre>
  
  <p>everything works as expected. But after calling:</p>
  
  <pre><code>figure.savefig(fileName, bbox_inches='tight', pad_inches=0.05)
  </code></pre>
  
  <p>File have been saved, BUT <strong>my figure on screen stops being updated</strong>. </p>
  
  <p>Any ideas how do I save figure to disk and still be able to update my fig on screen ?</p>