For the record, there's no official publication of CSS Backgrounds 4 yet and it still claims it is not ready for implementation.
Therefore I am currently working towards a First Public Working Draft, see https://github.com/w3c/csswg-drafts/issues/13062. Sebastian On Wed, 29 Oct 2025 at 15:44, Chromestatus <[email protected]> wrote: > *Contact emails* > [email protected] > > *Specification* > https://drafts.csswg.org/css-backgrounds-4/#background-position-longhands > > *Summary* > Defines the background image's position relative to one of its edges. This > syntax gives web authors a more flexible and responsive mechanisms to > define the background image position, instead of using fixed values that > need to be adapted to the window's or frame's size. This feature is applied > also to the "-webkit-mask-position" to ensure webcompat levels are the > same. > > *Blink component* > Blink>CSS > <https://issues.chromium.org/issues?q=customfield1222907:%22Blink%3ECSS%22> > > *Web Feature ID* > background-position <https://webstatus.dev/features/background-position> > > *Motivation* > One important motivation is interoperability, given that Chrome is the > only browser that lacks this syntax for the background-position-x/y > longhands. Additionally, the background-position shorthand, which sets both > the x/y positions, already supports the side-relative syntax, so the lack > of the same syntax in the longhands may confuse web developers. There is no > specific explainer, but this MDN page should be enough to understand the > feature: > https://developer.mozilla.org/en-US/docs/Web/CSS/background-position-x > > *Initial public proposal* > *No information provided* > > *TAG review* > *No information provided* > > *TAG review status* > Not applicable > > *Risks* > > > *Interoperability and Compatibility* > This feature doesn't imply any interoperability risk, but the contrary, > since Chrome needs to catch up in order to provide the same functionality > than Firefox and Safari. There is no back-compatibility risk, because the > old syntax is still valid if this feature is implemented. > > *Gecko*: Shipped/Shipping > > *WebKit*: Shipped/Shipping > > *Web developers*: Positive (https://issues.chromium.org/issues/40468636) The > issue has 15 votes by now. > > *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? > *No information provided* > > > *Debuggability* > The feature can be tested and debugged using the regular Chrome DevTools > support (eg, css style inspection) > > *Will this feature be supported on all six Blink platforms (Windows, Mac, > Linux, ChromeOS, Android, and Android WebView)?* > Yes > This feature is implemented in the blink's style module of the web engine, > so it's shared among all the platforms. > > *Is this feature fully tested by web-platform-tests > <https://chromium.googlesource.com/chromium/src/+/main/docs/testing/web_platform_tests.md>?* > Yes > > https://wpt.fyi/results/css/css-backgrounds/parsing?label=master&label=experimental&aligned&q=background-position-x > https://wpt.fyi/results/css/css-backgrounds/parsing?label=master&label=experimental&aligned&q=background-position-y > > *Flag name on about://flags* > *No information provided* > > *Finch feature name* > *No information provided* > > *Non-finch justification* > This is a catch-up change to align Chrome with the rest of the major web > engines (Firefox and Safari). It affects blink only and enables a new > syntax for a CSS property that Chrome already exposes to the web. > > *Rollout plan* > Will ship enabled for all users > > *Requires code in //chrome?* > False > > *Tracking bug* > https://issues.chromium.org/issues/40468636 > > *Estimated milestones* > Shipping on desktop 143 > Shipping on Android 143 > Shipping on WebView 143 > > *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/5073321259565056?gate=5131252113997824 > > *Links to previous Intent discussions* > Intent to Prototype: > https://groups.google.com/a/chromium.org/d/msgid/blink-dev/68d10a08.710a0220.5367c.009d.GAE%40google.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/6902284c.050a0220.56be2.0509.GAE%40google.com > <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/6902284c.050a0220.56be2.0509.GAE%40google.com?utm_medium=email&utm_source=footer> > . > -- 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/CAERejNaNAPXu3aMwCcQJjePK94CRs8yoDPkaiP8h19rR%3D_yNVw%40mail.gmail.com.
