"""
Choosing the thumbnail figure
=============================

This example demonstrates how to choose the figure that is displayed as the
thumbnail, if the example generates more than one figure. This is done by
specifying the keyword-value pair
``sphinx_gallery_thumbnail_number = <fig number>`` as a
comment somewhere below the docstring in the example file. In this example, we
specify that we wish for the second figure to be the thumbnail.
"""

# Code source: Óscar Nájera
# License: BSD 3 clause
# sphinx_gallery_tags = ["matplotlib","line-plot","thumbnails"]

import matplotlib.pyplot as plt
import numpy as np


def main():
    """Plot expoential functions."""
    x = np.linspace(-1, 2, 100)
    y = np.exp(x)

    plt.figure()
    plt.plot(x, y)
    plt.xlabel("$x$")
    plt.ylabel(r"$\exp(x)$")

    # The next line sets the thumbnail for the second figure in the gallery
    # (plot with negative exponential in orange)
    # sphinx_gallery_thumbnail_number = 2
    plt.figure()
    plt.plot(x, -np.exp(-x), color="orange", linewidth=4)
    plt.xlabel("$x$")
    plt.ylabel(r"$-\exp(-x)$")
    # To avoid matplotlib text output
    plt.show()


if __name__ == "__main__":
    main()
