On Sunday, September 11, 2022 at 7:20:45 AM UTC+2 fbea...@google.com wrote:
> On Fri, Sep 9, 2022 at 5:49 PM Yoav Weiss <yoavwe...@chromium.org> wrote: > >> >> >> 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. >> > > Thank you! > I've updated the spec to make it clear. See > https://github.com/WICG/user-preference-media-features-headers/pull/7 > Thanks, but that doesn't define that the hint is a high entropy one. Talking to Mike Taylor, it seems we can improve the CH Infra spec to make it clearer that any hint that's not low-entropy is a high entropy hint. Then your spec can get that definition for free. > > >> >> >>> >>> 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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