After a long war, I've finally got Toit working with my M5CoreInk board (GDEW0154M09 display). 🥳 I'm so close to getting a working display driver for this, but I clearly don't understand the

EPaper

API well enough yet. Can anyone answer these questions, please? * I've written a class that implements

initialize

and

draw-two-color

. Will that be enough, or are there other methods I need to look at? * What's the

commit

method for? * For

draw-two-color

, what's the format of the

pixels

array? I was expecting it to just horizontally scan the region from top-left to bottom-right, but it doesn't seem to be that simple... https://cdn.discordapp.com/attachments/1284562905278451722/1284562906129764464/IMG_8361.jpeg?ex=66e9102e&is=66e7beae&hm=0d912cc64871c48beb170a4828f8d6066f7bb19abd079c327383dab389dd4972&

Sorry. Didn't see the message earlier. I will try to investigate a bit today.

Thanks! 🙏

Fundamentally, you need to implement the

AbstractDriver

from the pixel-display package:

abstract class AbstractDriver:
  abstract width -> int
  abstract height -> int
  abstract flags -> int
  x-rounding -> int: return 8
  y-rounding -> int: return 8
  start-partial-update speed/int -> none:
  start-full-update speed/int -> none:
  clean left/int top/int right/int bottom/int -> none:
  commit left/int top/int right/int bottom/int -> none:
  draw-two-color l/int t/int r/int b/int pixels/ByteArray -> none:
    throw "Not a two-color driver"
  draw-two-bit l/int t/int r/int b/int plane0/ByteArray plane1/ByteArray -> none:
    throw "Not a two-bit driver"
  draw-gray-scale l/int t/int r/int b/int pixels/ByteArray -> none:
    throw "Not a gray-scale driver"
  draw-several-color l/int t/int r/int b/int pixels/ByteArray -> none:
    throw "Not a several-color driver"
  draw-true-color l/int t/int r/int b/int red/ByteArray green/ByteArray blue/ByteArray -> none:
    throw "Not a true-color driver"
  close -> none:

As you can see, it has all methods implemented with empty stubs. For a two-color display, it makes sense to override: -

width

-

height

-

flags

-

draw-to-color

-

commit

-

clean

? -

start-full-update

- eventually:

start-partial-update

... The

EPaper

class has plenty of methods, but none override the

EPaper

methods. These are thus just there as utility methods to help you implement the actualy methods. Looking at one of the implemented classes (like

waveshare-2-color-7-5.toit

) you can see that it implements: -

draw-to-color

-

clean

-

start-full-update

-

commit

- it also supports partial updates, but you can ignore these for now. It uses some additional help methods (

send-to-device_

,

redraw-rect_

...), but these are not required for the API. The

initialize

isn't required either, but you probably want it, and initialize automatically in the constructor (like the

Waveshare2Color154

).

Thanks for the info! I am now achingly close to getting this working. 🫠 https://cdn.discordapp.com/attachments/1284562905278451722/1286271649900920944/IMG_8398.jpg?ex=66ed4d53&is=66ebfbd3&hm=a0eb03a488ba8858bda3c20cf4b412999ab7ca9f8912050cd36405a38d42ff61&

Very cool!