.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "gallery/transforms/99.arrows_along_axes.py"
.. LINE NUMBERS ARE GIVEN BELOW.

.. only:: html

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

        :ref:`Go to the end <sphx_glr_download_gallery_transforms_99.arrows_along_axes.py>`
        to download the full example code

.. rst-class:: sphx-glr-example-title

.. _sphx_glr_gallery_transforms_99.arrows_along_axes.py:


=================
Arrows along axes
=================

Arrows along the axes can be put in barycentric coordinates using transforms
for ``TernaryAxes`` in combination with ``FancyArrowPatch``.

.. GENERATED FROM PYTHON SOURCE LINES 9-70



.. image-sg:: /gallery/transforms/images/sphx_glr_99.arrows_along_axes_001.svg
   :alt: 99.arrows along axes
   :srcset: /gallery/transforms/images/sphx_glr_99.arrows_along_axes_001.svg
   :class: sphx-glr-single-img





.. code-block:: Python

    import numpy as np

    import matplotlib.pyplot as plt
    from matplotlib.patches import ArrowStyle, FancyArrowPatch
    import mpltern  # noqa: F401

    ax = plt.subplot(projection='ternary')

    arrowstyle = ArrowStyle('simple', head_length=10, head_width=5)
    kwargs_arrow = {
        'transform': ax.transAxes,  # Used with ``ax.transAxesProjection``
        'arrowstyle': arrowstyle,
        'linewidth': 1,
        'clip_on': False,  # To plot arrows outside triangle
        'zorder': -10,  # Very low value not to hide e.g. tick labels.
    }

    # Start of arrows in barycentric coordinates.
    ta = np.array([ 0.0, -0.1,  1.1])
    la = np.array([ 1.1,  0.0, -0.1])
    ra = np.array([-0.1,  1.1,  0.0])

    # End of arrows in barycentric coordinates.
    tb = np.array([ 1.0, -0.1,  0.1])
    lb = np.array([ 0.1,  1.0, -0.1])
    rb = np.array([-0.1,  0.1,  1.0])

    # This transforms the above barycentric coordinates to the original Axes
    # coordinates. In combination with ``ax.transAxes``, we can plot arrows fixed
    # to the Axes coordinates.
    f = ax.transAxesProjection.transform

    tarrow = FancyArrowPatch(f(ta), f(tb), ec='C0', fc='C0', **kwargs_arrow)
    larrow = FancyArrowPatch(f(la), f(lb), ec='C1', fc='C1', **kwargs_arrow)
    rarrow = FancyArrowPatch(f(ra), f(rb), ec='C2', fc='C2', **kwargs_arrow)
    ax.add_patch(tarrow)
    ax.add_patch(larrow)
    ax.add_patch(rarrow)

    # To put the axis-labels at the positions consistent with the arrows above, it
    # may be better to put the axis-label-text directly as follows rather than
    # using e.g.  ax.set_tlabel.
    kwargs_label = {
        'transform': ax.transTernaryAxes,
        'backgroundcolor': 'w',
        'ha': 'center',
        'va': 'center',
        'rotation_mode': 'anchor',
        'zorder': -9,  # A bit higher on arrows, but still lower than others.
    }

    # Put axis-labels on the midpoints of arrows.
    tpos = (ta + tb) * 0.5
    lpos = (la + lb) * 0.5
    rpos = (ra + rb) * 0.5

    ax.text(*tpos, 'Top'  , color='C0', rotation=-60, **kwargs_label)
    ax.text(*lpos, 'Left' , color='C1', rotation= 60, **kwargs_label)
    ax.text(*rpos, 'Right', color='C2', rotation=  0, **kwargs_label)

    plt.show()


.. _sphx_glr_download_gallery_transforms_99.arrows_along_axes.py:

.. only:: html

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

    .. container:: sphx-glr-download sphx-glr-download-jupyter

      :download:`Download Jupyter notebook: 99.arrows_along_axes.ipynb <99.arrows_along_axes.ipynb>`

    .. container:: sphx-glr-download sphx-glr-download-python

      :download:`Download Python source code: 99.arrows_along_axes.py <99.arrows_along_axes.py>`


.. only:: html

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

    `Gallery generated by Sphinx-Gallery <https://sphinx-gallery.github.io>`_