Nice! Text sizing has been a longstanding wart in the web with it's unpredictability and inconsistent behavior. Thank you for investing to rationalize it! LGTM2
On Tue, Jan 20, 2026 at 5:37 PM 'Dan Clark' via blink-dev < [email protected]> wrote: > Thank you for the excellent explainer. It's a shame this behavior can't be > the default, but due to compat an opt-in makes sense. LGTM1. > > On Thursday, January 15, 2026 at 4:48:26 PM UTC-8 Chromestatus wrote: > >> *Contact emails* >> [email protected], [email protected] >> >> *Explainer* >> >> https://github.com/w3c/csswg-drafts/blob/main/css-env-1/explainers/meta-text-scale.md >> >> *Specification* >> https://drafts.csswg.org/css-fonts-5/#text-scale-meta >> >> *Summary* >> Makes the root element's default font size scale in proportion to both >> the operating system's and browser's text scale setting. This allows pages >> that follow best practices around font-relative units (i.e. use rem and em >> for font sizes and page elements that should change with the user's text >> size preferences) to respect the user's OS-level text scale setting. This >> also causes the browser to disable existing browser-based mechanisms (i.e. >> full-page zoom on windows) and heuristics (i.e. text autosizing on mobile). >> Now web developers can signal to the browser that the page is constructed >> in a way (i.e. with rem and em) that will scale well across various >> user-selected font size preferences. Similar to env(preferred-text-scale), >> which provides authors with a way to access the text scale; this API >> extends that by enabling scaling via the root element's default font size >> and opting-out of automatic text scaling. >> >> *Blink component* >> Blink>Accessibility >> <https://issues.chromium.org/issues?q=customfield1222907:%22Blink%3EAccessibility%22> >> >> *Web Feature ID* >> Missing feature >> >> *Motivation* >> Authors currently don't have an easy way to respect the OS-level text >> scale setting on all devices. It is practically impossible to detect and >> respect this on desktop. On mobile, there is env(preferred-text-scale), but >> authors would need to use it in calc() functions to set the root font-size >> and some media queries. They would need a lot of guidance to ensure it gets >> used correctly and there would be little variation in how they would use >> it. Therefore, it would be much easier for authors if they could continue >> to use font-relative units as they do now and the UA initial font-size was >> redefined to incorporate the OS-level text scale setting. >> >> *Initial public proposal* >> https://github.com/w3c/csswg-drafts/issues/12380 >> >> *TAG review* >> https://github.com/w3ctag/design-reviews/issues/1172 >> >> *TAG review status* >> Issues addressed >> >> *Risks* >> >> >> *Interoperability and Compatibility* >> Compat – no issues as it's a new feature Interop – none really – even if >> other browsers don't implement it's a progressive enhancement >> >> *Gecko*: No signal ( >> https://github.com/mozilla/standards-positions/issues/1326) >> >> *WebKit*: No signal ( >> https://github.com/WebKit/standards-positions/issues/587) >> >> *Web developers*: Positive ( >> https://github.com/w3c/csswg-drafts/issues/12380) Positive emoji votes >> on the initial proposal >> >> *Other signals*: >> >> *Activation* >> We intend to do some outreach after the feature has baked on Stable. Some >> ideas are discussed at the end of this TAG review comment: >> https://github.com/w3ctag/design-reviews/issues/1172#issuecomment-3667481287 >> >> *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? >> No higher risk. This opt-in feature has WebView-specific behaviors. The >> goal of the WebView-specific parts is to allow authors to ensure their >> pages render identically on Chrome and WebView. Today renderings may not be >> identical due to some WebView font-sizing quirks. See commit message at >> https://chromium-review.googlesource.com/c/chromium/src/+/7280046 for >> more info. >> >> >> *Debuggability* >> *No information provided* >> >> *Will this feature be supported on all six Blink platforms (Windows, Mac, >> Linux, ChromeOS, Android, and Android WebView)?* >> Yes >> >> *Is this feature fully tested by web-platform-tests >> <https://chromium.googlesource.com/chromium/src/+/main/docs/testing/web_platform_tests.md>?* >> No >> Not tested in WPT because there is no API to simulate changing user font >> size preferences. The wpt_internal tests are at >> https://source.chromium.org/search?q=file:meta&sq=&ss=chromium%2Fchromium%2Fsrc:third_party%2Fblink%2Fweb_tests%2Fwpt_internal%2Fcss%2Fcss-fonts%2F >> There are other automated WebView java tests and C++ Unit tests. >> >> *Flag name on about://flags* >> *No information provided* >> >> *Finch feature name* >> TextScaleMetaTag >> >> *Rollout plan* >> Will ship enabled for all users >> >> *Requires code in //chrome?* >> False >> >> *Tracking bug* >> https://crbug.com/430566925 >> >> *Measurement* >> Added WebDX UseCounter in >> https://chromium-review.googlesource.com/c/chromium/src/+/7267330 >> >> *Estimated milestones* >> Shipping on desktop 146 >> Shipping on Android 146 >> Shipping on WebView 146 >> >> *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). >> *No information provided* >> >> *Link to entry on the Chrome Platform Status* >> https://chromestatus.com/feature/5112244702674944?gate=5080483318857728 >> >> *Links to previous Intent discussions* >> Intent to Prototype: >> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAOZbSt0S4JY2pHY23SVKTFR63Q3ak5Z8RXmqqNhHkXigb2feKw%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/4ca24d8b-07e9-4da3-86d7-5f92f5fc7a5fn%40chromium.org > <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/4ca24d8b-07e9-4da3-86d7-5f92f5fc7a5fn%40chromium.org?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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