I've recently switched to a black-and-white e-ink smartphone with the motivation of withdrawing from the attention economy somewhat and it's a genuinely cool piece of hardware. While the majority of my needs are met by this device there are a few things I'd like to have which don't work terribly well with the e-ink screen. I'm planning to implement a couple of projects to fill these gaps, at the moment I'm planning a Lemmy frontend and an OpenRouter frontend specifically for e-ink. Both are to be browser-based rather than native, to maximise compatibility and because I'm much more familiar with the web than Android development.
I would like to study the principles of sound e-ink UI design before approaching these projects to avoid creating unusable slop, in particular I am not entirely sure how to approach treating the refreshes as a first-class aspect of the design when I can't control them from the browser, and how to apply comprehensible UI conventions when a greyscale, high-contrast display is the target.
Some specific problems I have out of the gate are:
* Streaming LLM output to the screen is basically the worst-case scenario for e-ink, I need to buffer it and paint it in chunks without this becoming horrible to use.
* Ghosting is a serious problem, browsing HN on the device is a particularly obvious example. Ideally I want to avoid scrolling as far as possible and rely on pagination instead, which I feel has the potential to become annoying if not done well.
* Given I must rely exclusively on layout and type to carry the UI, what design languages emphasise these qualities best? My gut says the early Mac OS versions wouldn't be a bad place to start, this seems relevant given the display constraints of the early macs.
I would greatly appreciate any advice on the design and implementation of e-ink UIs from people with practical experience in this area. This is purely to scratch a personal itch, once they're nailed down I'll put them out in the wild under the GPL.
You obviously cannot always avoid this, so when there is a hard requirement for continuous feedback, use a degraded/cheap transient representation and refresh at commit of that action. With E-Ink, every interaction has to be a trade off between ghosting and latency. One common pattern I ended up coming back to is intermediate states that optimize for latency at the expense of ghosting until the UI action is 'complete'. This will allow refreshes to be associated with the satisfaction of finality. Funny enough, many of them harken back to old UI paradigms from when computer graphics weren't as powerful as today. When resizing, I simply draw the outline of the shape with a fast update mode that tolerates more ghosting until the user releases their finger or stylus, at which point, after a small lag to account for an 'oops, just a tiny bit bigger/smaller', I do a localized refresh of the union of the old + new area.
The outline itself is deliberately faint, so the refresh doesn't have to be as intense if its a small delta.
For your streaming LLM case, I would recommend doing it in chunks, like you said, perhaps doing a hard refresh of everything but the input box + moving the tail of last sent message + beginning of stream to the top upon send. Of course, this implies that you know exactly how long the response will be, which you don't. The challenge will be coming up with a UI paradigm that doesn't make it look awkward if the response only goes down to the middle of the screen while also nicely doing a clean refresh pre-emptively if it's clear it will overflow and need to move to the top. For the former case, find some way where it looks not completely awkward if it's partial and then do refresh of the chat history area and move it to its proper fitted position once the user clicks on the input box again to type their next reply. For the latter, perhaps embedding some kind of remaining space meter at the bottom that indicates when you'd need to do this move + refresh action (don't directly label it that way) would enable the user to anticipate it more and be less frustrated when it happens, as they are psychologically awaiting the next part of the answer/reasoning, not surprised at a sudden flash.
For the actual streaming, you'll have to ensure that your text alignment works in such a way that once a line is rendered to the screen, its placement is final (in other words, no streaming intra-word, as you need to know if the word will fit in remaining space on the line before rendering it). Basically, avoid retroactive reflow like a PDF document with a fixed layout, not like this text box I am typing in with a resize handle at the lower right. You'll also probably want to disable scrolling during generation as well, or at least make some sort of discrete pagination mechanism for going back and forth.
In any event, I look forward to seeing whatever it is you're building!