screen
======

.. py:module:: screen

.. autoapi-nested-parse::

   The image on the panel, kept on flash between updates.

   A partial refresh needs the image the panel shows as the "old" one, but
   the display controller loses its RAM on every init (the reset after deep
   sleep), and with config.DISPLAY_OFF_IN_SLEEP also its supply. So the image
   is saved here after every refresh: 15000 bytes per fetch, spread by the
   file system's wear levelling over the free flash.



Attributes
----------

.. autoapisummary::

   screen.SCREEN_FILE


Functions
---------

.. autoapisummary::

   screen.save
   screen.load


Module Contents
---------------

.. py:data:: SCREEN_FILE
   :value: 'screen.bin'


.. py:function:: save(buffer, path=SCREEN_FILE)

   Store the image; a power cut leaves the previous file intact.


.. py:function:: load(size, path=SCREEN_FILE)

   The saved image, or None if there is none of the expected size.