import matplotlib
matplotlib.use("WXAgg")

from matplotlib import pyplot as plt
import numpy
import threading
import wx
import time

x = []
y = []


fig = plt.figure()
ax = fig.add_subplot(111)
line = ax.plot(x,y)[0]
ax.set_ylim(-1,1)

def update(x, y):
    """put code to update plot or other GUI stuff here"""
    x = numpy.array(x)
    y = numpy.array(y)
    line.set_data(x, y)
    fig.canvas.draw()
    ax.set_xlim(x.min(), x.max())


class ProcessThread(threading.Thread):        
    def start(self):
        self._running = True
        super(ProcessThread, self).start()
        
    def stop(self):
        self._running = False
        self.join(5.0)
        
    def run(self):
        """Do GPIO stuff here, but don't do GUI stuff"""
        t = time.time()
        while self._running:
            now = time.time()
            x.append(now-t)
            y.append(numpy.cos(now-t))
            wx.CallAfter(update, x , y) #calls update in the GUI thread
            time.sleep(0.2)


thd = ProcessThread()
thd.start()
plt.show()
thd.stop()