.. note::
    :class: sphx-glr-download-link-note

    Click :ref:`here <sphx_glr_download_gallery_text_labels_and_annotations_usetex_demo.py>` to download the full example code
.. rst-class:: sphx-glr-example-title

.. _sphx_glr_gallery_text_labels_and_annotations_usetex_demo.py:


===========
Usetex Demo
===========

Shows how to use latex in a plot.

Also refer to the :doc:`/tutorials/text/usetex` guide.



.. image:: /gallery/text_labels_and_annotations/images/sphx_glr_usetex_demo_001.png
    :class: sphx-glr-single-img






.. code-block:: default


    import numpy as np
    import matplotlib.pyplot as plt
    plt.rc('text', usetex=True)

    # interface tracking profiles
    N = 500
    delta = 0.6
    X = np.linspace(-1, 1, N)
    plt.plot(X, (1 - np.tanh(4 * X / delta)) / 2,    # phase field tanh profiles
             X, (1.4 + np.tanh(4 * X / delta)) / 4, "C2",  # composition profile
             X, X < 0, 'k--')                        # sharp interface

    # legend
    plt.legend(('phase field', 'level set', 'sharp interface'),
               shadow=True, loc=(0.01, 0.48), handlelength=1.5, fontsize=16)

    # the arrow
    plt.annotate("", xy=(-delta / 2., 0.1), xytext=(delta / 2., 0.1),
                 arrowprops=dict(arrowstyle="<->", connectionstyle="arc3"))
    plt.text(0, 0.1, r'$\delta$',
             {'color': 'black', 'fontsize': 24, 'ha': 'center', 'va': 'center',
              'bbox': dict(boxstyle="round", fc="white", ec="black", pad=0.2)})

    # Use tex in labels
    plt.xticks((-1, 0, 1), ('$-1$', r'$\pm 0$', '$+1$'), color='k', size=20)

    # Left Y-axis labels, combine math mode and text mode
    plt.ylabel(r'\bf{phase field} $\phi$', {'color': 'C0', 'fontsize': 20})
    plt.yticks((0, 0.5, 1), (r'\bf{0}', r'\bf{.5}', r'\bf{1}'), color='k', size=20)

    # Right Y-axis labels
    plt.text(1.02, 0.5, r"\bf{level set} $\phi$", {'color': 'C2', 'fontsize': 20},
             horizontalalignment='left',
             verticalalignment='center',
             rotation=90,
             clip_on=False,
             transform=plt.gca().transAxes)

    # Use multiline environment inside a `text`.
    # level set equations
    eq1 = r"\begin{eqnarray*}" + \
          r"|\nabla\phi| &=& 1,\\" + \
          r"\frac{\partial \phi}{\partial t} + U|\nabla \phi| &=& 0 " + \
          r"\end{eqnarray*}"
    plt.text(1, 0.9, eq1, {'color': 'C2', 'fontsize': 18}, va="top", ha="right")

    # phase field equations
    eq2 = r'\begin{eqnarray*}' + \
          r'\mathcal{F} &=& \int f\left( \phi, c \right) dV, \\ ' + \
          r'\frac{ \partial \phi } { \partial t } &=& -M_{ \phi } ' + \
          r'\frac{ \delta \mathcal{F} } { \delta \phi }' + \
          r'\end{eqnarray*}'
    plt.text(0.18, 0.18, eq2, {'color': 'C0', 'fontsize': 16})

    plt.text(-1, .30, r'gamma: $\gamma$', {'color': 'r', 'fontsize': 20})
    plt.text(-1, .18, r'Omega: $\Omega$', {'color': 'b', 'fontsize': 20})

    plt.show()


.. _sphx_glr_download_gallery_text_labels_and_annotations_usetex_demo.py:


.. only :: html

 .. container:: sphx-glr-footer
    :class: sphx-glr-footer-example



  .. container:: sphx-glr-download

     :download:`Download Python source code: usetex_demo.py <usetex_demo.py>`



  .. container:: sphx-glr-download

     :download:`Download Jupyter notebook: usetex_demo.ipynb <usetex_demo.ipynb>`


.. only:: html

 .. rst-class:: sphx-glr-signature

    Keywords: matplotlib code example, codex, python plot, pyplot
    `Gallery generated by Sphinx-Gallery
    <https://sphinx-gallery.readthedocs.io>`_