"""

=======

Textbox

=======

Allowing text input with the Textbox widget.

You can use the Textbox widget to let users provide any text that needs to be

displayed, including formulas. You can use a submit button to create plots

with the given input.

"""

import numpy as np

import matplotlib.pyplot as plt

from matplotlib.widgets import TextBox

fig, ax = plt.subplots()

plt.subplots_adjust(bottom=0.2)

t = np.arange(-2.0, 2.0, 0.001)

s = t ** 2

initial_text = "t ** 2"

l, = plt.plot(t, s, lw=2)

def submit(text):

ydata = eval(text)

l.set_ydata(ydata)

ax.set_ylim(np.min(ydata), np.max(ydata))

plt.draw()

axbox = plt.axes([0.1, 0.05, 0.8, 0.075])

text_box = TextBox(axbox, 'Evaluate', initial=initial_text)

text_box.on_submit(submit)

plt.show()