[max7219digit] add actions for the common display functions.

components/display/max7219digit.rst

@@ -70,6 +70,48 @@ Configuration variables:
 - **chip_lines_style** (*Optional*): How are the lines in Multiline Mode connected? Possible values are ``zigzag`` and ``snake``. Defaults to ``snake``
 - **flip_x** (*Optional*, boolean): Flip the horizontal axis on the screen. Defaults to ``false``.
 
+.. _display-max7219digit_actions:
+
+Actions
+-------
+The following actions are replicas of the LAMBDA functions shown in the next section. 
+
+.. _display-max7219digit_actions_invert_on_off>:
+
+`MAX7219.invert_on` & `MAX7219.invert_off` Action
+=================================================
+
+This action  ``MAX7219.invert_on`` will invert the display. So background pixels are on and texts pixels are
+off. ``MAX7219.invert_off`` sets the display back to normal. The background pixels are only set at the next update, the pixels drawn in
+the various function like print, line, etc. are directly influenced by the invert command.
+
+.. _display-max7219digit_actions_turn_on_off:
+
+`MAX7219.turn_on` & `MAX7219.turn_off` Action
+=============================================
+
+The display can be switched on and off "dynamically" with the actions `MAX7219.turn_on` & `MAX7219.turn_off`.
+
+
+.. _display-max7219digit_actions_reverse_off:
+
+`MAX7219.reverse_on` & `MAX7219.reverse_off` Action
+===================================================
+
+With this actions you can reverse the display direction from left to right to right to left.
+
+
+.. _display-max7219digit_actions_intensity:
+
+`MAX7219.intensity` Action
+===========================
+
+The intensity of the screen can be set "dynamically" within the lambda code with the following command: it.intensity(``0`` .. ``15``).
+
+- **intensity** (int): The intensity with which the MAX7219 should drive the outputs. Range is
+  from ``0``, least intense to ``15`` the brightest. Defaults to ``15``.
+
+
 .. _display-max7219digit_lambda:
 
 Rendering Lambda