

.. _sphx_glr_gallery_api_line_with_text.py:


=======================
Artist within an artist
=======================

Show how to override basic methods so an artist can contain another
artist.  In this case, the line contains a Text instance to label it.




.. image:: /gallery/api/images/sphx_glr_line_with_text_001.png
    :align: center





.. code-block:: python

    import numpy as np
    import matplotlib.pyplot as plt
    import matplotlib.lines as lines
    import matplotlib.transforms as mtransforms
    import matplotlib.text as mtext


    class MyLine(lines.Line2D):
        def __init__(self, *args, **kwargs):
            # we'll update the position when the line data is set
            self.text = mtext.Text(0, 0, '')
            lines.Line2D.__init__(self, *args, **kwargs)

            # we can't access the label attr until *after* the line is
            # inited
            self.text.set_text(self.get_label())

        def set_figure(self, figure):
            self.text.set_figure(figure)
            lines.Line2D.set_figure(self, figure)

        def set_axes(self, axes):
            self.text.set_axes(axes)
            lines.Line2D.set_axes(self, axes)

        def set_transform(self, transform):
            # 2 pixel offset
            texttrans = transform + mtransforms.Affine2D().translate(2, 2)
            self.text.set_transform(texttrans)
            lines.Line2D.set_transform(self, transform)

        def set_data(self, x, y):
            if len(x):
                self.text.set_position((x[-1], y[-1]))

            lines.Line2D.set_data(self, x, y)

        def draw(self, renderer):
            # draw my label at the end of the line with 2 pixel offset
            lines.Line2D.draw(self, renderer)
            self.text.draw(renderer)

    # Fixing random state for reproducibility
    np.random.seed(19680801)


    fig, ax = plt.subplots()
    x, y = np.random.rand(2, 20)
    line = MyLine(x, y, mfc='red', ms=12, label='line label')
    #line.text.set_text('line label')
    line.text.set_color('red')
    line.text.set_fontsize(16)


    ax.add_line(line)


    plt.show()

**Total running time of the script:** ( 0 minutes  0.032 seconds)



.. container:: sphx-glr-footer


  .. container:: sphx-glr-download

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



  .. container:: sphx-glr-download

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

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

    `Generated by Sphinx-Gallery <https://sphinx-gallery.readthedocs.io>`_
