"""Test the new %gui command.  Run this in ipython as

In [1]: %gui [backend]

In [2]: %run switchgui [backend]

where the optional backend can be one of:  qt4, gtk, tk, wx.

Because of subtle difference in how Matplotlib handles the different GUI 
toolkits (in things like draw and show), minor modifications to this script
have to be made for Tk to get it to work with the 0.99 and below releases
of Matplotlib.  However, in the future, Matplotlib should be able to have 
similar logic for all the toolkits, as they are all now using PyOS_InputHook.
"""

import sys
import time

from  IPython.lib import inputhook

gui = inputhook.current_gui()
if gui is None:
    gui = 'qt4'
    inputhook.enable_qt4(app=True)

backends = dict(wx='wxagg', qt4='qt4agg', gtk='gtkagg', tk='tkagg')

import matplotlib
matplotlib.use(backends[gui])
matplotlib.interactive(True)

import matplotlib
from matplotlib import pyplot as plt, mlab, pylab
import numpy as np

from numpy import *
from matplotlib.pyplot import *

x = np.linspace(0,pi,500)

print "A plot has been created"
line, = plot(x,sin(2*x))
inputhook.spin() # This has to be removed for Tk


print "Now, we will update the plot..."
print
for i in range(1,51):
    print i, 
    sys.stdout.flush()
    line.set_data(x,sin(x*i))
    plt.title('i=%d' % i)
    plt.draw()
    inputhook.spin() # This has to be removed for Tk