On Thu, May 22, 2025 at 7:07 PM Domenic Denicola <[email protected]> wrote:
> > > On Fri, May 23, 2025 at 9:00 AM Chromestatus < > [email protected]> wrote: > >> Contact emails [email protected], [email protected] >> >> Explainer https://davidsgrogan.github.io/env-explainer.html >> >> Specification https://drafts.csswg.org/css-env-1/#text-zoom >> >> Summary >> >> Exposes a user's preferred font scale to CSS. Currently, it is not >> practical for a page to detect if the user has changed their preferred font >> size via the Operating System's preferences. This CSS environment variable >> will reflect the scale chosen by the user. >> >> >> Blink component Blink>Accessibility >> <https://issues.chromium.org/issues?q=customfield1222907:%22Blink%3EAccessibility%22> >> >> TAG review https://github.com/w3ctag/design-reviews/issues/1101 >> >> TAG review status Pending >> >> Risks >> >> >> Interoperability and Compatibility >> >> None >> >> >> *Gecko*: No signal ( >> https://github.com/mozilla/standards-positions/issues/1229) >> >> *WebKit*: No signal ( >> https://github.com/WebKit/standards-positions/issues/499) >> >> *Web developers*: Positive ( >> https://github.com/w3c/csswg-drafts/issues/10674) This proposal started >> with a request from a BBC developer >> >> *Other signals*: >> >> WebView application risks >> >> Does this intent deprecate or change behavior of existing APIs, such that >> it has potentially high risk for Android WebView-based applications? >> >> None >> >> >> Debuggability >> >> This can be debugged using existing devtools support by connecting to a >> device. We have a plan for making this easier at >> https://crbug.com/419595584. >> >> >> Will this feature be supported on all six Blink platforms (Windows, Mac, >> Linux, ChromeOS, Android, and Android WebView)? No >> >> Initial support will be limited to Android, which has limited practical >> ability to respect the OS font scale today. On Windows, we scale the entire >> browser in response to the OS setting, and some followup work is needed to >> support this while not double-zooming. >> > > I'd like to learn more about this from a compat and interop perspective. > From skimming the explainer, this seems like a complicated problem space. > Interop: there's a pretty simple fallback for browsers that don't support this env variable: env(preferred-text-scale, 1). We have 1p and 3p partners that have started to experiment with this variable. They needed a good rollout story. We are also thinking about @supports ( https://github.com/w3c/csswg-drafts/issues/3576#issuecomment-2881619620) for env variables to make this easier and more powerful in the future. > > > If we never ship support on desktop, and authors start using this feature, > what will the user experience be? > Same as today. Users will continue to use browser zoom on desktop (ctrl +/-), which is not a big deal (compared to mobile) because it's relatively easy to use and there's usually plenty of screen space to avoid lawnmower swiping. Mobile is where we've heard demand for this feature because authors relay their users' subpar experience. We haven't heard about user pain on desktop. If this ends up being mobile only, that is not our desired end-state, but it's not catastrophic because the zoom options on desktop are less problematic. > > If we don't ship support on desktop for 10 milestones, but then suddenly > do, what will the user experience be? > No matter when we ship on desktop, whether today or in 10 milestones, we'll need to provide an opt-in for authors (explainer has a sketch of our opt-in proposal <https://github.com/w3c/csswg-drafts/blob/main/css-env-1/explainers/env-preferred-text-scale.md#new-meta-viewport-key-for-changing-text-scale>) to avoid definite double scaling on Windows (because of its automatic page zoom) and potential double scaling on the other Desktop platforms (because they change how font-size:medium is resolved in response to the UA-slider). Windows is the most complicated desktop platform for us to add support for OS-level font scaling, mainly because Chrome does a full browser zoom of both the browser’s UI and the web page <https://github.com/w3c/csswg-drafts/blob/main/css-env-1/explainers/env-preferred-text-scale.md#windows-11>in response to the OS font slider. We can't unilaterally disable this automatic scaling because users may rely on it. So if an author wants better control over their page scaling on Windows, they'll have to signal to the browser to not do this automatic scaling. When they've signaled that, the browser will intelligently populate the environment variable (meaning values other than 1 are eligible). The other desktop platforms are degenerate/easier cases of windows; as such our proposed opt-in mechanism will handle them properly as well ("for free"). Mobile doesn't have any potential double scaling issues (no UA-slider to affect font-size:medium), so no opt-in mechanism is needed. If we do ship the opt-in and env var on desktop in 10 milestones, users who have changed their OS-level font settings will get improved font sizes on sites that use the opt-in and env var. Sites that had used the env var just for mobile will not change when viewed on desktop; there will be no spontaneous breakage. What we want to ship now, just the env variable on mobile, always populated to the value of the OS-level setting, is a small incremental platform change, is sufficient to fix the highest-demand problem, is required for some complex sites (some of our partners), and doesn't block later desktop work. > > You mentioned Windows, but what about macOS, Linux, ChromeOS, and Android > WebView? > >> >> Apologies for the omissions. Android WebView — this will also be supported at initial launch Desktop platforms including CrOS – the environment variable will be available with this launch but will always return a value of 1, essentially being a no-op. As described above, we intend to later intelligently populate the value on desktop, which will require an opt-in. > >> Is this feature fully tested by web-platform-tests >> <https://chromium.googlesource.com/chromium/src/+/main/docs/testing/web_platform_tests.md> >> ? Yes >> >> This is tested with internal WPT tests due to lack of support for OS font >> scale setting in tests. >> https://github.com/web-platform-tests/wpt/issues/12725 >> >> >> Flag name on about://flags None >> >> Finch feature name CSSPreferredTextScale >> >> Rollout plan Will ship enabled for all users >> >> Requires code in //chrome? False >> >> Tracking bug https://crbug.com/397737223 >> >> Measurement UseCounter: >> https://chromestatus.com/metrics/feature/popularity#CSSEnvironmentVariable_PreferredTextScale >> >> Estimated milestones >> Shipping on Android 138 >> >> Anticipated spec changes >> >> Open questions about a feature may be a source of future web compat or >> interop issues. Please list open issues (e.g. links to known github issues >> in the project for the feature specification) whose resolution may >> introduce web compat/interop risk (e.g., changing to naming or structure of >> the API in a non-backward-compatible way). >> https://github.com/w3c/csswg-drafts/issues/10674 >> >> Link to entry on the Chrome Platform Status >> https://chromestatus.com/feature/5328467685801984?gate=6195643460354048 >> >> Links to previous Intent discussions Intent to Prototype: >> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAOZbSt1dSWUwuFD%2Bu%3DwGXf-ubdgh8K%3D0oj13%3DkrvADSOM41xtw%40mail.gmail.com >> >> >> This intent message was generated by Chrome Platform Status >> <https://chromestatus.com>. >> >> -- >> 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 [email protected]. >> To view this discussion visit >> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/682fba7d.170a0220.2aa17e.152d.GAE%40google.com >> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/682fba7d.170a0220.2aa17e.152d.GAE%40google.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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