Skip to content

[css-color-hdr] 2.4 "two dynamic-range-limit-mix values" should be "two or more ..." #11694

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
squelart opened this issue Feb 11, 2025 · 2 comments
Labels
css-color-hdr CSS HDR extension

Comments

@squelart
Copy link
Contributor

#10271 added interpolation between multiple values of dynamic-range-limit, which can also work on more than two values, as seen in the example and WPT computed.html.
However the preceding paragraph 2.4 still starts with "This function takes two dynamic-range-limit values".
It should be updated to "two or more".

Bonus: For completeness, could it also support just one value? I think the algorithm to get the computed value would still work.
The zero-value case is already implicitly handled by "If the sum of all percentages is 0%, then the function is invalid."

@svgeesus
Copy link
Contributor

Added the "two or more".

Supporting a single value needs more discussion, I think; so leaving this issue open for now.

@css-meeting-bot
Copy link
Member

The CSS Working Group just discussed https://github.com/w3c/csswg-drafts/issues/11788, and agreed to the following:

  • RESOLVED: require strict inequality for H1 and H2
  • RESOLUTION: allow single value, well defined
The full IRC log of that discussion <ChrisL> topic: https://github.com//issues/11788
<ChrisL> github: https://github.com//issues/11788
<ChrisL> ccameron: this is to avoid a divide by zero
<ccameron> the epsilon should only be used to color match (very exactly) with an image
<ccameron> this feature is good enough without eps
<ccameron> it's purely numerical
<ccameron> can set to like 0.5 even
<ccameron> the epsilon value is in the gain application color space (which is linear, and is either "base image" primaries or "alternate image" primaries)
<ccameron> in practice, that's sRGB, P3 or Rec2020 primaries
<ccameron> what's the gain application color space?
<ccameron> primaries of the first space specified is most "normal" default
<ChrisL> github: https://github.com//issues/11787
<ChrisL> RESOLVED: require strict inequality for H1 and H2
<ChrisL> github: https://github.com//issues/11694
<ChrisL> Most edits done, need to discuss about allowing a single value or not
<ChrisL> agenda is https://lists.w3.org/Archives/Member/w3c-css-wg/2025AprJun/0002.html
<ChrisL> WPT allows single value
<ChrisL> agenda is https://lists.w3.org/Archives/Member/w3c-css-wg/2025AprJun/0002.html
<ChrisL> RESOLUTION: allow single value, well defined
<ccameron> https://github.com//issues/11558

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
css-color-hdr CSS HDR extension
Projects
None yet
Development

No branches or pull requests

3 participants