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

.. only:: html

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

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

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

.. _sphx_glr__gallery_events_paint_image.py:


Paint an Image
==============

Click and drag the mouse to paint in the image

.. GENERATED FROM PYTHON SOURCE LINES 7-71



.. image-sg:: /_gallery/events/images/sphx_glr_paint_image_001.webp
   :alt: paint image
   :srcset: /_gallery/events/images/sphx_glr_paint_image_001.webp
   :class: sphx-glr-single-img





.. code-block:: Python


    # test_example = false

    import numpy as np
    import fastplotlib as fpl
    import pygfx

    figure = fpl.Figure(size=(700, 560))

    # add a blank image
    image = figure[0, 0].add_image(np.zeros((100, 100)), vmin=0, vmax=255)

    painting = False  # use to toggle painting state


    @image.add_event_handler("pointer_down")
    def on_pointer_down(ev: pygfx.PointerEvent):
        # start painting when mouse button is down
        global painting

        # get image element index, (x, y) pos corresponds to array (column, row)
        col, row = ev.pick_info["index"]

        # increase value of this image element
        image.data[row, col] = np.clip(image.data[row, col] + 50, 0, 255)

        # toggle on painting state
        painting = True

        # disable controller until painting stops when mouse button is un-clicked
        figure[0, 0].controller.enabled = False


    @image.add_event_handler("pointer_move")
    def on_pointer_move(ev: pygfx.PointerEvent):
        # continue painting when mouse pointer is moved
        global painting

        if not painting:
            return

        # get image element index, (x, y) pos corresponds to array (column, row)
        col, row = ev.pick_info["index"]

        image.data[row, col] = np.clip(image.data[row, col] + 50, 0, 255)


    @figure.renderer.add_event_handler("pointer_up")
    def on_pointer_up(ev: pygfx.PointerEvent):
        # toggle off painting state
        global painting
        painting = False

        # re-enable controller
        figure[0, 0].controller.enabled = True


    figure.show()

    # NOTE: `if __name__ == "__main__"` is NOT how to use fastplotlib interactively
    # please see our docs for using fastplotlib interactively in ipython and jupyter
    if __name__ == "__main__":
        print(__doc__)
        fpl.loop.run()


.. rst-class:: sphx-glr-timing

   **Total running time of the script:** (0 minutes 0.345 seconds)


.. _sphx_glr_download__gallery_events_paint_image.py:

.. only:: html

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

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

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

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

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

    .. container:: sphx-glr-download sphx-glr-download-zip

      :download:`Download zipped: paint_image.zip <paint_image.zip>`


.. only:: html

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

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