LGTM2 On Wed, Mar 4, 2026 at 9:26 AM Mike Taylor <[email protected]> wrote:
> LGTM1 - thanks for catching us up here. > On 3/4/26 8:51 a.m., Rune Lillesveen wrote: > > *Contact emails* > [email protected] > > *Specification* > https://drafts.csswg.org/css-color-5/#contrast-color > > *Summary* > This function is used to meet contrast requirements for accessibility. The > contrast-color() function can be used anywhere in CSS where a color value > is expected. It takes a color value argument, and returns either 'black' or > 'white' depending on which of them gives the highest contrast against the > color argument. > > The contrast algorithm is UA-defined per spec. > > Blink's implementation uses an existing WCAG-based implementation: > > > https://source.chromium.org/chromium/chromium/src/+/37ec5d082cb1df8959857653854677200fdb334c:ui/gfx/color_utils.h;l=43-51;bpv=0 > > This is the same as the Firefox implementation[1] and Safari which have a > detailed description about the WCAG algorithm and its shortcomings in their > blog post[2]. > > [1] > https://github.com/mozilla-firefox/firefox/blob/main/servo/components/style/values/computed/color.rs#L104-L128 > [2] https://webkit.org/blog/16929/contrast-color/ > > *Blink component* > Blink>CSS > <https://issues.chromium.org/issues?q=customfield1222907:%22Blink%3ECSS%22> > > *Web Feature ID* > contrast-color <https://webstatus.dev/features/contrast-color> > > *Motivation* > This feature will make it easier for authors to meet contrast requirements > for accessibility. The feature is already shipped in the two other major > engines. contrast-color() is also part of Interop 2026. > > *Initial public proposal* > *No information provided* > > *TAG review* > *No information provided* > > *TAG review status* > Not applicable > > *Risks* > > > *Interoperability and Compatibility* > *No information provided* > > *Gecko*: Shipped/Shipping ( > https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/Values/color_value/contrast-color#browser_compatibility > ) > > *WebKit*: Shipped/Shipping ( > https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/Values/color_value/contrast-color#browser_compatibility > ) > > *Web developers*: No signals > > *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* > *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>?* > Yes, but given that the contrast algorithm is UA-defined per spec, most > expectations allow both white and black as the returned contrast-color(). > > > https://wpt.fyi/results/css/css-color/animation/contrast-color-interpolation.html > https://wpt.fyi/results/css/css-color/contrast-color-001.html > > https://wpt.fyi/results/css/css-color/contrast-color-currentcolor-inherited.html > > https://wpt.fyi/results/css/css-color/parsing/color-computed-contrast-color-function.html > > https://wpt.fyi/results/css/css-color/parsing/color-invalid-contrast-color-function.html > > https://wpt.fyi/results/css/css-color/parsing/color-valid-contrast-color-function.html > > https://wpt.fyi/results/css/css-color/parsing/contrast-color-function-calc-container.html > > https://wpt.fyi/results/css/css-images/color-stop-contrast-color-currentcolor-invalidation.html > > *Flag name on about://flags* > *No information provided* > > *Finch feature name* > *No information provided* > > *Non-finch justification* > *No information provided* > > *Rollout plan* > Will ship enabled for all users > > *Requires code in //chrome?* > False > > *Tracking bug* > https://crbug.com/40142548 > > *Estimated milestones* > Shipping on desktop 147 > Shipping on Android 147 > Shipping on WebView 147 > > *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/4841046007742464?gate=6582039723769856 > > *Links to previous Intent discussions* > Intent to Prototype: > https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CACuPfeTv1YNDgDkc5SiCDwDf0ZCn0sWd7qdfUzuQvejpEut8tA%40mail.gmail.com > > > This intent message was generated by Chrome Platform Status > <https://chromestatus.com/>. > > -- > Rune Lillesveen > > -- > 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/CACuPfeTdz0K67%2BRocOJHjABqXBLiMcUwFUMrhLrhvhGGfWGKeg%40mail.gmail.com > <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CACuPfeTdz0K67%2BRocOJHjABqXBLiMcUwFUMrhLrhvhGGfWGKeg%40mail.gmail.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/cea2459b-90f7-45e0-bef0-efa04555a948%40chromium.org > <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/cea2459b-90f7-45e0-bef0-efa04555a948%40chromium.org?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/CADsXd2PMTahvCZczFkzwL1MoPbt25dv6QARuPgW%3D4yChmnzTzA%40mail.gmail.com.
