Detect e-ink device and/or EinkBro

[leosutic]

From a website creator perspective it would be nice to detect e-ink devices so that a more appropriate CSS stylesheet can be applied / animations can be disabled / etc.

As far as I can tell, the only semi-reliable way is to measure the screen update interval and if it is more than some threshold assume e-ink. (The pixelDepth and colorDepth properties don't work since browsers lie and claim 24-bit.) The problem here is that this process takes at least as long as the threshold to execute - if you turn on e-ink mode for all devices with a frame rate of one frame per 300ms or longer, that code must wait 300ms before it can confirm the frame rate and switch.

Since EinkBro is, from what I can tell, the browser people use on e-ink devices, detecting it would, I think, correlate with an e-ink device the overwhelming majority of times. But for good reasons it has a generic UA-string, so no luck there. I noticed a ˋX-Requested-Withˋ-header, but this is not accessible in JavaScript from the page itself and so requires server-side support.

I'm not well enough versed in browser compatibility issues, but is there some way that EinkBro could be detected? (Or does anyone have a solution for how to detect an e-ink device?)