* Initialize the EPaper display on the MagTag at start.
* Tweak the display send to take a const buffer.
* Correct Luma math
* Multiply the blue component, not add.
* Add all of the components together before dividing. This
reduces the impact of truncated division.
It was fixed as 0/0 even though it used to get it from the current
SPI state. This makes it more explicit with kwargs.
Thanks to magpie_lark and kmatocha on the Adafruit Support forum
for finding the issue: https://forums.adafruit.com/viewtopic.php?f=60&t=162515
It's designed to minimize RAM footprint by using Sprites to
represent objects on the screen. The object model also facilitates
partial screen updating which reduces the bandwidth needed to display.
This is all handled in C. Python simply manipulates the objects with
the ability to synchronize to frame timing.
