Intent to Ship: CSS color space display-p3-linear

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Christopher Cameron

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Oct 22, 2025, 5:58:39 AM (4 days ago) Oct 22
to blink-dev, Philip Jägenstedt
Hello blink-dev!

This very simple feature adds display-p3-linear as a CSS color space. This has been added to the CSS specification and has a bazillion WPT tests from:
It has been requested as a candidate for interop 2026:

More relevant to the topics close to my heart are the fact that this is a very good space for physically based rendering and high dynamic range. Adding this space to the list of canvas spaces is a separate feature over at:


Contact emails
ccam...@chromium.org

Specification
No information provided

Summary
Add display-p3-linear CSS color space

Blink component
Blink>CSS

Web Feature ID
color-function

Motivation
No information provided

Initial public proposal
No information provided

TAG review
No information provided

TAG review status
Not applicable

Risks


Interoperability and Compatibility
No information provided

Gecko: No signal

WebKit: No signal

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)?
No

Is this feature fully tested by web-platform-tests?
No


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

Estimated milestones

No milestones specified



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/5162372125818880?gate=4761603400663040

This intent message was generated by Chrome Platform Status.

Daniel Bratell

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Oct 22, 2025, 6:20:26 AM (4 days ago) Oct 22
to Christopher Cameron, blink-dev, Philip Jägenstedt

The form seems fields seem to be mostly left empty. I don't think anything should be empty (though a N/A may fit some things). I have questions, but they would mostly be answered by filling in the form and re-posting it.

/Daniel

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Christopher Cameron

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Oct 22, 2025, 6:42:19 AM (4 days ago) Oct 22
to Daniel Bratell, blink-dev, Philip Jägenstedt
Let me know what questions you have.

Indeed, almost everything is N/A (I've filled them out in the feature if you want to look).

Daniel Bratell

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Oct 22, 2025, 9:07:10 AM (4 days ago) Oct 22
to Christopher Cameron, blink-dev, Philip Jägenstedt

The page at https://www.chromium.org/blink/guidelines/web-platform-changes-guidelines lists most of the things we want to know before sending a feature out into the wild wild world.

One of the main questions regards compatibility. We want what we do to end up in a web where browsers agree on how something should be rendered which is why we typically require new features to probe Mozilla and WebKit through their web standards positions (unless they have already shipped).

Another aspect of compatibility, and risk, is about web compatibility. Will this change break things? Are we really, really sure? That is why we typically require every feature to have a finch flag so that at least Google Chrome can turn off something that causes unexpected problems. 

When I say "typical", it's because no rule fits all, but then we instead need to know why a certain rule does not apply. 

You will also see that we ask for some info texts, explainer, specification, that many implementers consider obvious. Often it is not obvious for other people though, and these texts end up in official blog posts and in other external communication.

/Daniel

Philip Jägenstedt

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Oct 22, 2025, 10:08:22 AM (4 days ago) Oct 22
to Daniel Bratell, Christopher Cameron, blink-dev
I had a chat with Chris about this.

https://chromestatus.com/feature/5162372125818880 has been updated to link to the spec, and a standards position for Mozilla was filed:

This already landed in WebKit:
https://wpt.fyi/results/css/css-color?label=master&label=experimental&aligned&q=display-p3-linear (the failure of display-p3-linear-006.html is only off by 1 for a bunch of pixels)

So I think this is quite a straightforward case, LGTM1!

Chris Harrelson

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Oct 22, 2025, 11:22:36 AM (4 days ago) Oct 22
to Philip Jägenstedt, Daniel Bratell, Christopher Cameron, blink-dev

一丝

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Oct 23, 2025, 12:00:00 AM (4 days ago) Oct 23
to blink-dev, Chris Harrelson, Daniel Bratell, Christopher Cameron, blink-dev, Philip Jägenstedt

It appears the new color space in WPT still lacks testing for CSS gradients. Could this be added?

e.g.

`background-image: linear-gradient(to right in display-p3-linear, red, blue);`

Philip Jägenstedt

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Oct 23, 2025, 2:07:19 AM (4 days ago) Oct 23
to 一丝, blink-dev, Chris Harrelson, Daniel Bratell, Christopher Cameron
Good catch, gradients in linear color space is a very plausible use case that we should test. Chris, can you add a test for this? I presume there are other tests that can be copied.

Christopher Cameron

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Oct 24, 2025, 3:03:48 AM (3 days ago) Oct 24
to Philip Jägenstedt, 一丝, blink-dev, Chris Harrelson, Daniel Bratell
I've updated the CSS gradient tests for this here:

There are also canvas gradient WPT tests (which is a feature that hasn't made it into the spec yet). I've updated the tests and our (speculative) implementation to include display-p3-linear.

Philip Jägenstedt

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Oct 24, 2025, 3:22:38 AM (3 days ago) Oct 24
to Christopher Cameron, 一丝, blink-dev, Chris Harrelson, Daniel Bratell
Great, thank you Chris!

Mike Taylor

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Oct 24, 2025, 9:40:12 AM (2 days ago) Oct 24
to Philip Jägenstedt, Christopher Cameron, 一丝, blink-dev, Chris Harrelson, Daniel Bratell
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