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

.. only:: html

    .. meta::
        :keywords: codex

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

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

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

.. _sphx_glr_gallery_widgets_span_selector.py:


=============
Span Selector
=============

The `.SpanSelector` is a mouse widget that enables selecting a range on an
axis.

Here, an x-range can be selected on the upper axis; a detailed view of the
selected range is then plotted on the lower axis.

.. note::

    If the SpanSelector object is garbage collected you will lose the
    interactivity.  You must keep a hard reference to it to prevent this.

.. GENERATED FROM PYTHON SOURCE LINES 17-67

.. code-block:: Python


    import matplotlib.pyplot as plt
    import numpy as np

    from matplotlib.widgets import SpanSelector

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

    fig, (ax1, ax2) = plt.subplots(2, figsize=(8, 6))

    x = np.arange(0.0, 5.0, 0.01)
    y = np.sin(2 * np.pi * x) + 0.5 * np.random.randn(len(x))

    ax1.plot(x, y)
    ax1.set_ylim(-2, 2)
    ax1.set_title('Press left mouse button and drag '
                  'to select a region in the top graph')

    line2, = ax2.plot([], [])


    def onselect(xmin, xmax):
        indmin, indmax = np.searchsorted(x, (xmin, xmax))
        indmax = min(len(x) - 1, indmax)

        region_x = x[indmin:indmax]
        region_y = y[indmin:indmax]

        if len(region_x) >= 2:
            line2.set_data(region_x, region_y)
            ax2.set_xlim(region_x[0], region_x[-1])
            ax2.set_ylim(region_y.min(), region_y.max())
            fig.canvas.draw_idle()


    span = SpanSelector(
        ax1,
        onselect,
        "horizontal",
        useblit=True,
        props=dict(alpha=0.5, facecolor="tab:blue"),
        interactive=True,
        drag_from_anywhere=True
    )
    # Set useblit=True on most backends for enhanced performance.


    plt.show()




.. image-sg:: /gallery/widgets/images/sphx_glr_span_selector_001.png
   :alt: Press left mouse button and drag to select a region in the top graph
   :srcset: /gallery/widgets/images/sphx_glr_span_selector_001.png, /gallery/widgets/images/sphx_glr_span_selector_001_2_00x.png 2.00x
   :class: sphx-glr-single-img





.. GENERATED FROM PYTHON SOURCE LINES 68-74

.. admonition:: References

   The use of the following functions, methods, classes and modules is shown
   in this example:

   - `matplotlib.widgets.SpanSelector`


.. _sphx_glr_download_gallery_widgets_span_selector.py:

.. only:: html

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

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

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

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

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


.. only:: html

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

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