On Fri, Sep 9, 2022 at 4:21 PM 'Thomas Steiner' via blink-dev < blink-dev@chromium.org> wrote:
> Contact emails > > fbeauf...@chromium.org, to...@chromium.org > > Explainer > > > https://github.com/wicg/user-preference-media-features-headers/blob/main/README.md > > Specification > > > https://wicg.github.io/user-preference-media-features-headers/#sec-ch-prefers-reduced-motion > It seems worthwhile to properly specify that the hints in question are high-entropy hints that are not sent without an opt-in. Based on https://github.com/WebKit/standards-positions/issues/15, it doesn't seem like that is clear. > > API spec > > Yes > > Summary > > The Sec-CH-Prefers-Reduced-Motion client hint is modeled after the > prefers-reduced-motion user preference media feature as defined in Media > Queries Level 5. This headers follows Sec-CH-Prefers-Color-Scheme, which > was described in > https://groups.google.com/a/chromium.org/g/blink-dev/c/tEZ4RVsP1ms. > > Blink component > > Blink>CSS > > Motivation > > CSS media queries, and specifically user preference media features like > prefers-reduced-motion, have a potentially significant impact on the > amount of CSS that needs to be delivered by a page, and on the experience > the user is going to have when the page loads. > > It is a best practice to not load CSS responsible for animations in the > critical rendering path if the user prefers reduced motion, but to instead > only load said CSS if the user doesn't mind motion. One way of doing so is > via <link media>. However, high-traffic sites like Google Search that > wish to honor user preference media features like prefers-reduced-motion > and that inline CSS for performance reasons, need to know about the motion > preferences (or other user preference media features respectively) ideally > at request time, so that the initial HTML payload already has the right CSS > inlined. > > TAG review > > https://github.com/w3ctag/design-reviews/issues/632 > > TAG review status > > Unsatisfied > > Demo link > > https://sec-ch-prefers-reduced-motion.glitch.me/ > > Debuggability > > Developers can change the Sec-CH-Prefers-Reduced-Motion client hint > header value by emulating motion preferences via DevTools in the Rendering > panel like they can do with the Sec-CH-Prefers-Color-Scheme client hint > header today. > > Measurement > > The kClientHintsPrefersReducedMotion WebFeature tracks > Sec-CH-Prefers-Reduced-Motion client hint usage. > > Risks > > > Interoperability and Compatibility > There are no particular compatibility risks. > > Interoperability is still pending on other browser vendors replying. > Support for Client Hints in general is not enthusiastic though. > > > Signals from other implementations (Gecko, WebKit): > > Gecko: Pending (https://github.com/mozilla/standards-positions/issues/526) > > WebKit: Pending ( > https://lists.webkit.org/pipermail/webkit-dev/2021-May/031856.html, now > migrated to https://github.com/WebKit/standards-positions/issues/15) > > Web / Framework developers: Positive (WICG proposal Issue: > https://github.com/WICG/proposals/issues/30 with feedback from developers > working for Facebook > <https://github.com/WICG/proposals/issues/30#issuecomment-854962840> and > Magento > <https://github.com/WICG/proposals/issues/30#issuecomment-850873790>. > Twitter: https://twitter.com/kilianvalkhof/status/1392404416335056896. > The proposal was initially discussed in > https://github.com/w3c/csswg-drafts/issues/4162 and received positive > feedback via 16 Likes and 3 supportive comments: > https://github.com/w3c/csswg-drafts/issues/4162#issuecomment-621047333, > https://github.com/w3c/csswg-drafts/issues/4162#issuecomment-631400330, > and https://github.com/w3c/csswg-drafts/issues/4162#issuecomment-645742958). > Google Search is interested in this header, too. > > Ergonomics: > > N/A > > Activation: > > Developers will include Sec-CH-Prefers-Reduced-Motion in the response > headers Accept-CH and Critical-CH to let the browser know that they’re > interested in the motion preferences. If supported, the request header > Sec-CH-Prefers-Reduced-Motion will be populated with the appropriate > value. > > Is this feature fully tested by web-platform-tests? > > Yes. https://wpt.fyi/results/client-hints. > > Tracking bug > > https://crbug.com/1361871 > > Link to entry on the Chrome Platform Status > > https://chromestatus.com/feature/5141804190531584 > > -- > You received this message because you are subscribed to the Google Groups > "blink-dev" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to blink-dev+unsubscr...@chromium.org. > To view this discussion on the web visit > https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CALgRrL%3DgTkCO%3DmZErYjf1BCyQAPFNNMv3KJFPpFEFV3Ev6%3DrtA%40mail.gmail.com > <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CALgRrL%3DgTkCO%3DmZErYjf1BCyQAPFNNMv3KJFPpFEFV3Ev6%3DrtA%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "blink-dev" group. 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