"""
======================
Zoom region inset axes
======================

Example of an inset axes and a rectangle showing where the zoom is located.
"""

from matplotlib import cbook
import matplotlib.pyplot as plt
import numpy as np


def get_demo_image():
    z = cbook.get_sample_data("axes_grid/bivariate_normal.npy", np_load=True)
    # z is a numpy array of 15x15
    return z, (-3, 4, -4, 3)

fig, ax = plt.subplots(figsize=[5, 4])

# make data
Z, extent = get_demo_image()
Z2 = np.zeros((150, 150))
ny, nx = Z.shape
Z2[30:30+ny, 30:30+nx] = Z

ax.imshow(Z2, extent=extent, origin="lower")

# inset axes....
axins = ax.inset_axes([0.5, 0.5, 0.47, 0.47])
axins.imshow(Z2, extent=extent, origin="lower")
# sub region of the original image
x1, x2, y1, y2 = -1.5, -0.9, -2.5, -1.9
axins.set_xlim(x1, x2)
axins.set_ylim(y1, y2)
axins.set_xticklabels('')
axins.set_yticklabels('')

ax.indicate_inset_zoom(axins)

plt.show()

#############################################################################
#
# ------------
#
# References
# """"""""""
#
# The use of the following functions and methods is shown in this example:

import matplotlib
matplotlib.axes.Axes.inset_axes
matplotlib.axes.Axes.indicate_inset_zoom
matplotlib.axes.Axes.imshow