.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "gallery/widgets/range_slider.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_range_slider.py>`
        to download the full example code

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

.. _sphx_glr_gallery_widgets_range_slider.py:


======================================
Thresholding an Image with RangeSlider
======================================

Using the RangeSlider widget to control the thresholding of an image.

The RangeSlider widget can be used similarly to the `.widgets.Slider`
widget. The major difference is that RangeSlider's ``val`` attribute
is a tuple of floats ``(lower val, upper val)`` rather than a single float.

See :doc:`/gallery/widgets/slider_demo` for an example of using
a ``Slider`` to control a single float.

See :doc:`/gallery/widgets/slider_snap_demo` for an example of having
the ``Slider`` snap to discrete values.

.. GENERATED FROM PYTHON SOURCE LINES 18-64

.. code-block:: Python


    import matplotlib.pyplot as plt
    import numpy as np

    from matplotlib.widgets import RangeSlider

    # generate a fake image
    np.random.seed(19680801)
    N = 128
    img = np.random.randn(N, N)

    fig, axs = plt.subplots(1, 2, figsize=(10, 5))
    fig.subplots_adjust(bottom=0.25)

    im = axs[0].imshow(img)
    axs[1].hist(img.flatten(), bins='auto')
    axs[1].set_title('Histogram of pixel intensities')

    # Create the RangeSlider
    slider_ax = fig.add_axes([0.20, 0.1, 0.60, 0.03])
    slider = RangeSlider(slider_ax, "Threshold", img.min(), img.max())

    # Create the Vertical lines on the histogram
    lower_limit_line = axs[1].axvline(slider.val[0], color='k')
    upper_limit_line = axs[1].axvline(slider.val[1], color='k')


    def update(val):
        # The val passed to a callback by the RangeSlider will
        # be a tuple of (min, max)

        # Update the image's colormap
        im.norm.vmin = val[0]
        im.norm.vmax = val[1]

        # Update the position of the vertical lines
        lower_limit_line.set_xdata([val[0], val[0]])
        upper_limit_line.set_xdata([val[1], val[1]])

        # Redraw the figure to ensure it updates
        fig.canvas.draw_idle()


    slider.on_changed(update)
    plt.show()




.. image-sg:: /gallery/widgets/images/sphx_glr_range_slider_001.png
   :alt: Histogram of pixel intensities
   :srcset: /gallery/widgets/images/sphx_glr_range_slider_001.png, /gallery/widgets/images/sphx_glr_range_slider_001_2_00x.png 2.00x
   :class: sphx-glr-single-img





.. GENERATED FROM PYTHON SOURCE LINES 65-71

.. admonition:: References

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

   - `matplotlib.widgets.RangeSlider`


.. _sphx_glr_download_gallery_widgets_range_slider.py:

.. only:: html

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

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

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

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

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


.. only:: html

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

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