> I've inquired in a few places (including HN) about what app design guidelines / practices exist for e-ink. Apparently there are none. This is disheartening.
That probably has a lot to do with the intended audience of e-ink. The most consumer facing application are e-readers, a market that is served by a handful of companies. Most of the remaining applications are commercial.
With respect to guidance, you may want to check out the Mobileread forums. There are a few people who develop software for e-readers there. Notably in the section for Kobo, and likely for other e-readers as well. There are also some open source projects that you can look into. KOReader and Plato come to mind. I also recall a mention of an e-ink guideline in a video by Ralph S Bacon on YouTube, so there is something out there. (Apparently colour e-ink displays should be refreshed at a regular, albeit long, interval in order to maintain image quality.) I realize that most of these source are for palm-sized, or smaller, screens but at least they will understand the physical properties of e-ink.
My own experience, a couple of months using an e-ink device heavily, is that there's a great deal of foregone potential.
Battery life, recharge time, outdoor viewability, overall display quality, and the fact that the devices really are general-purpose / mobile devices (there are Linux, Android, and a few other OS variants out there) means that apps can be tailored to them.
What I like about the BOOX is that it's a pretty good e-reader, and ... somewhat OK Android tablet. That's not faint praise, it's actually "I kinda wish it were a worse tablet so I wouldn't be so distracted by it". Given the present state of mobile device addiction, that could be a fairly broad potential market. Even a small percentage of 4--8 billion is a large number.
Use as a terminal disiplay (using Termux) is surprisingly good. Given that terminals were originally based on teletypes, this isn't entirely surprising.
I'll follow up on your suggestions, thanks.
And can confirm that any e-ink device should be refreshed fairly frequently. The BOOX default is 20 displays, in practice 5--10 would be preferable, though that depends in part on the display mode used (the BOOX has five, from highest quality render to fastest update/paint rate).
That probably has a lot to do with the intended audience of e-ink. The most consumer facing application are e-readers, a market that is served by a handful of companies. Most of the remaining applications are commercial.
With respect to guidance, you may want to check out the Mobileread forums. There are a few people who develop software for e-readers there. Notably in the section for Kobo, and likely for other e-readers as well. There are also some open source projects that you can look into. KOReader and Plato come to mind. I also recall a mention of an e-ink guideline in a video by Ralph S Bacon on YouTube, so there is something out there. (Apparently colour e-ink displays should be refreshed at a regular, albeit long, interval in order to maintain image quality.) I realize that most of these source are for palm-sized, or smaller, screens but at least they will understand the physical properties of e-ink.