Re: [csswg-drafts] [mediaqueries] media query for relative animation performance (#13316)

The primary motivation for `update: fast` vs `update: slow` was not intended to distinguish between "normal" devises with good or mediocre performance, but with entirely different categories of devices: phone (low or high end) vs e-ink reader, or things so underpowered that even with a good screen, they're hardly faster than an e-ink device. Not so much "how smooth are your animations?", and more "Can you animate at all? If you can't animate, are you a piece of paper (`none`), or are you at least capable of changing what's on the screen at all once rendered, even if it's going to take a while?"

At the very low end of performance, it is true that there's quite a bit of a gray zone at the frontier between slow animations, and "you call that an animation? I barely got 2 frames between the start and end of this transition…"

The problem is, this is quite subjective. Do you draw the line at 1fps? 5fps? 15fps? Anything lower than 60fps? It could be nice to leave the choice to developers, give them a `refresh-rate` query, but I don't think that's feasible. The frame rate can heavily depend on the content in addition to the device; there's not even a requirement that the UA must update the whole screen at once, so different parts of the screen could be refreshing at different rates… 

I wonder if we just need one more level:
* cannot change at all. e.g.: paper
* can update, but not meaningfully animate, even for simple pages. Measuring "reload time" (maybe a few 100 ms to a few s) makes more sense than measuring fps. e.g.: classic e-ink, severely underpowered devices (think embedded controller, not low-end smart-phone)
* can animate, but not well. Maybe up to something like 10fps
* Can animate smoothly

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Received on Friday, 9 January 2026 11:32:17 UTC