Many displays don't have the TE pin exposed. But those that do have the
pin (for example, the PyPortal) can use it to synchronize writing a new
image to the display. When implemented correctly, tearing can be avoided
entirely.
This commit also changes the LCD refresh direction to either
top-to-bottom or left-to-right depending on the rotation. Previously it
might refresh from right-to-left or bottom-to-top. This has little
impact on code that doesn't use the TE line, but code that does now only
needs to worry about two cases (top-to-bottom and left-to-right) instead
of four.
(Unfortunately, it appears that the hardware doesn't support changing
the major LCD refresh order so code that wants to do tear-free rendering
still needs to care about these two cases).
* Unify the Rotation type, so that SetRotation can be used in
interfaces.
* Add Rotation() method to these displays, so that the current
rotation can be read.
* Change SetRotation() so that it can return an error (if the given
rotation isn't supported).
Ayke van Laethem
sago35
BCG