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

    Click :ref:`here <sphx_glr_download_auto_tutorials_viz_timers.py>` to download the full example code
.. rst-class:: sphx-glr-example-title

.. _sphx_glr_auto_tutorials_viz_timers.py:


===============
Using a timer
===============

This example shows how to create a simple animation using a timer callback.

We will use a sphere actor that generates many spheres of different colors,
radii and opacity. Then we will animate this actor by rotating and changing
global opacity levels from inside a user defined callback.

The timer will call this user defined callback every 200 milliseconds. The
application will exit after the callback has been called 100 times.



.. image:: /auto_tutorials/images/sphx_glr_viz_timers_001.png
    :class: sphx-glr-single-img





.. code-block:: python



    import numpy as np
    from fury import window, actor, ui
    import itertools

    xyz = 10 * np.random.rand(100, 3)
    colors = np.random.rand(100, 4)
    radii = np.random.rand(100) + 0.5

    scene = window.Scene()

    sphere_actor = actor.sphere(centers=xyz,
                                colors=colors,
                                radii=radii)

    scene.add(sphere_actor)

    showm = window.ShowManager(scene,
                               size=(900, 768), reset_camera=False,
                               order_transparent=True)

    showm.initialize()

    tb = ui.TextBlock2D(bold=True)

    # use itertools to avoid global variables
    counter = itertools.count()


    def timer_callback(_obj, _event):
        cnt = next(counter)
        tb.message = "Let's count up to 100 and exit :" + str(cnt)
        showm.scene.azimuth(0.05 * cnt)
        sphere_actor.GetProperty().SetOpacity(cnt/100.)
        showm.render()
        if cnt == 100:
            showm.exit()


    scene.add(tb)

    # Run every 200 milliseconds
    showm.add_timer_callback(True, 200, timer_callback)

    showm.start()

    window.record(showm.scene, size=(900, 768), out_path="viz_timer.png")

**Total running time of the script:** ( 0 minutes  20.466 seconds)


.. _sphx_glr_download_auto_tutorials_viz_timers.py:


.. only :: html

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



  .. container:: sphx-glr-download

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



  .. container:: sphx-glr-download

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


.. only:: html

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

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