"""
======
Timers
======

Simple example of using general timer objects. This is used to update
the time placed in the title of the figure.
"""
import matplotlib.pyplot as plt
import numpy as np
from datetime import datetime


def update_title(axes):
    axes.set_title(datetime.now())
    axes.figure.canvas.draw()

fig, ax = plt.subplots()

x = np.linspace(-3, 3)
ax.plot(x, x ** 2)

# Create a new timer object. Set the interval to 100 milliseconds
# (1000 is default) and tell the timer what function should be called.
timer = fig.canvas.new_timer(interval=100)
timer.add_callback(update_title, ax)
timer.start()

# Or could start the timer on first figure draw
#def start_timer(evt):
#    timer.start()
#    fig.canvas.mpl_disconnect(drawid)
#drawid = fig.canvas.mpl_connect('draw_event', start_timer)

plt.show()
