

.. _sphx_glr_gallery_widgets_buttons.py:


=======
Buttons
=======

Constructing a simple button GUI to modify a sine wave.

The ``next`` and ``previous`` button widget helps visualize the wave with
new frequencies.




.. image:: /gallery/widgets/images/sphx_glr_buttons_001.png
    :align: center





.. code-block:: python


    import numpy as np
    import matplotlib.pyplot as plt
    from matplotlib.widgets import Button

    freqs = np.arange(2, 20, 3)

    fig, ax = plt.subplots()
    plt.subplots_adjust(bottom=0.2)
    t = np.arange(0.0, 1.0, 0.001)
    s = np.sin(2*np.pi*freqs[0]*t)
    l, = plt.plot(t, s, lw=2)


    class Index(object):
        ind = 0

        def next(self, event):
            self.ind += 1
            i = self.ind % len(freqs)
            ydata = np.sin(2*np.pi*freqs[i]*t)
            l.set_ydata(ydata)
            plt.draw()

        def prev(self, event):
            self.ind -= 1
            i = self.ind % len(freqs)
            ydata = np.sin(2*np.pi*freqs[i]*t)
            l.set_ydata(ydata)
            plt.draw()

    callback = Index()
    axprev = plt.axes([0.7, 0.05, 0.1, 0.075])
    axnext = plt.axes([0.81, 0.05, 0.1, 0.075])
    bnext = Button(axnext, 'Next')
    bnext.on_clicked(callback.next)
    bprev = Button(axprev, 'Previous')
    bprev.on_clicked(callback.prev)

    plt.show()

**Total running time of the script:** ( 0 minutes  0.172 seconds)



.. only :: html

 .. container:: sphx-glr-footer


  .. container:: sphx-glr-download

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



  .. container:: sphx-glr-download

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


.. only:: html

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

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