title: Is it possible to auto scale plot axis using Python matplotlib.animation.FuncAnimation() with blit=True?
body: <p>I am trying to plot some receiving data from a sensor using matplotlib.animation.FuncAnimation(). In addition, I would like to use blit=True because as far as I know it makes the program more efficient (taking advantage of the already plotted values and only refreshing the new ones). </p>
  
  <p>However, when I use blit=True and autoscale_view() and relim() the x_axis values are not autoscaling and stay all time the same. So my question is if this is possible or blit option can only be used for "loop" o "repeating" graphs in which the x_axis is always the same (on Internet I only found examples likes these: sine graph, spirals...). Additionally, when using blit my graph seems to be blind or cut-out at some limit points (bottom and right side of the graph) so all points cannot be seen.</p>
  
  <p>This is a example of my code (plotting random values instead of reading from sensor):</p>
  
  <pre><code>import sys, os, random, matplotlib
  import numpy as np
  from datetime import datetime
  from PyQt5 import QtCore, QtWidgets
  from PyQt5.QtWidgets import QApplication, QVBoxLayout, QSizePolicy, QWidget
  from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
  from matplotlib.figure import Figure
  import matplotlib.pyplot as plt
  from matplotlib.animation import FuncAnimation
  
  
  class MyMplCanvas(FigureCanvas):
      def __init__(self, parent=None, width=5, height=4, dpi=100):
          fig = Figure(figsize=(width, height), dpi=dpi)
          self.ax = fig.add_subplot(1,1,1)
          FigureCanvas.__init__(self, fig)
          FigureCanvas.setSizePolicy(self,
                                     QtWidgets.QSizePolicy.Expanding,
                                     QtWidgets.QSizePolicy.Expanding)
          FigureCanvas.updateGeometry(self)
  
  class ApplicationWindow(QtWidgets.QMainWindow):
      def __init__(self):
          QtWidgets.QMainWindow.__init__(self)
          self.setAttribute(QtCore.Qt.WA_DeleteOnClose)
          self.setWindowTitle("application main window")
          self.main_widget = QtWidgets.QWidget(self)
          self.xdata = []
          self.ydata = []
          vbox = QtWidgets.QVBoxLayout(self.main_widget)
          self.canvas =  MyMplCanvas( self.main_widget,width=6, height=6, dpi=100) ###attention###
          vbox.addWidget(self.canvas)
          self.setLayout(vbox)
          self.main_widget.setFocus()
          self.setCentralWidget(self.main_widget)
  
          self.line, = self.canvas.ax.plot_date(self.xdata, self.ydata,'-')
          self.canvas.ax.tick_params(axis='x', rotation=50)
          self.ani = FuncAnimation(self.canvas.figure, self.update_line, frames=self.gen_function_time, blit=True ,interval=1000)
  
      def gen_function_time(self):
          while True: 
              self.now = datetime.now()
              yield self.now
  
      def update_line(self, frame):
          self.xdata.append(frame)
          self.ydata.append(1+np.random.randint(-3,3))
          self.line.set_data(self.xdata, self.ydata)
          self.canvas.ax.relim()
          self.canvas.ax.autoscale_view()
          return self.line,
  
  
  if __name__ == "__main__":
      App = QApplication(sys.argv)
      aw = ApplicationWindow()
      aw.show()
      App.exit()
      sys.exit(App.exec_())
  </code></pre>