title: on click pause the real time plot of data
body: <p>I simply want to put a pause clause to my plot where I can pause the real time stream voluntarily. 
  This is what I am trying. This is an edited code. It s making two subplots: scatter and pie chart. I am able to pause the scatter plot but when I pause pie chart disappears.</p>
  
  <pre><code>def onClick(event):
      global pause
      pause ^= True
  fig = plt.figure()
  fig.canvas.mpl_connect('button_press_event', onClick)
  plt.show()
  
  while t&lt;ran2:       
        if not pause:
           ax = fig.add_subplot(2,1,1)
           ay = fig.add_subplot(2,1,2)
           mdfmt = md.DateFormatter('%H:%M')
           ax.xaxis.set_major_formatter(mdfmt)
           cmap=cm.jet
           g=s[t:t+4]
           h=[]
           for i in g:
               if i == 'Match':
                   h.append(1)
               else:
                   h.append(0)
           ax.scatter(x[t:t+4],y[t:t+4],c=h,s=150,marker='&lt;',edgecolor='None', cmap = cm.jet)
           ax.set_xlabel('Time')
           ax.set_ylabel('Action')
           mindate = min(data_mat['Date'].ix[t:t+4])
           ax.set_title('Alarm System for site SPFD02 on date %s'%mindate)
           yt=[-1,0,1]
           ax.set_yticks(yt)
           ax.set_yticklabels(('Closed','Not Ack','Assigned'))
           ax.set_xlim(x[t],x[t+4])    
  
  # for pie chart
           l = 'Match','No-Match'
           colors = ['red','blue']
           j = s[t:t+4].count('Match')
           z = z + j
           k = s[t:t+4].count('No-Match')
           r = r + k
           sizes = [z,r]
           ay.pie(sizes,labels = l, colors = colors, autopct='%1.1f%%', shadow=True, startangle=140)
           ay.set_aspect('equal')        
           t=t+1
     else:
          print 'paused'
  plt.pause(0.1)
  plt.cla() 
  </code></pre>