%matplotlib notebook
import numpy as np
import matplotlib.pyplot as plt
from ipywidgets import interact, IntSlider, RadioButtons
from mpl_toolkits.mplot3d import Axes3D

delta = 0.02
x = y = np.arange(-4.0, 4.02, delta)
X, Y = np.meshgrid(x, y)
Z1 = np.exp(-X**2 - Y**2)
Z2 = np.exp(-(X - 1.2)**2 - (Y - 0.7)**2)
Z3 = np.exp(-(X + 0.5)**2 - (Y + 1.4)**2)
Z = (Z1 - Z2 - Z3) * 2
fig = plt.figure(figsize=(9.5, 4))
ax1 = fig.add_subplot(121, projection='3d')
ax2 = fig.add_subplot(122)

ax1.plot_surface(X, Y, Z,alpha=0.5, cmap='gnuplot')
l2, = ax1.plot([], [], [], c='m')
l3, = ax1.plot([], [], [], c='g')

ax1.set_xlabel('x')
ax1.set_ylabel('y')
line2, = ax2.plot([],[],'m')
line3, = ax2.plot([],[],'g')
ax2.set_xlim(X.min(),X.max())
ax2.set_ylim(-abs(Z).max(),abs(Z).max())
ax2.set_ylabel('Z')


num = IntSlider(min=0, max=400)
direction = RadioButtons(options = ['x','y'])
@interact(num=num, direction=direction)
def plot(num,direction):

    if direction == 'x':
        l3.set_xdata((np.nan))
        l3.set_ydata((np.nan))
        l3.set_3d_properties((np.nan))
        line3.set_xdata([])
        line3.set_ydata([])

        l2.set_xdata((X[num,:]))
        l2.set_ydata((Y[num,:]))
        l2.set_3d_properties((Z[num,:]))

        line2.set_xdata(X[num,:])
        line2.set_ydata(Z[num,:])
        ax2.set_xlabel('x')


    else:# direction == 'y':
        l2.set_xdata((np.nan))
        l2.set_ydata((np.nan))
        l2.set_3d_properties((np.nan))
        line2.set_xdata([])
        line2.set_ydata([])
        l3.set_xdata((X[:,num]))
        l3.set_ydata((Y[:,num]))
        l3.set_3d_properties((Z[:,num]))
        line3.set_xdata(Y[:,num])
        line3.set_ydata(Z[:,num])
        ax2.set_xlabel('y')

plt.show()