18:53:56 <RRSAgent> RRSAgent has joined #css
18:54:00 <RRSAgent> logging to https://www.w3.org/2025/04/09-css-irc
18:54:07 <ChrisL> rrsagent, start meeting
18:54:07 <RRSAgent> I'm logging. I don't understand 'start meeting', ChrisL.  Try /msg RRSAgent help
18:54:47 <ChrisL> present+
18:54:58 <ChrisL> rrsagent, here
18:54:58 <RRSAgent> See https://www.w3.org/2025/04/09-css-irc#T18-54-58
18:55:19 <ChrisL> rrsagent, make logs public
18:57:11 <ChrisL> agenda https://lists.w3.org/Archives/Member/w3c-css-wg/2025AprJun/0002.html
18:57:31 <ChrisL> rrsagent, make minutes
18:57:33 <RRSAgent> I have made the request to generate https://www.w3.org/2025/04/09-css-minutes.html ChrisL
18:58:28 <ChrisL> ChrisL has changed the topic to: HDR Breakout, agenda https://lists.w3.org/Archives/Member/w3c-css-wg/2025AprJun/0002.html
19:03:19 <ChrisL> github: https://github.com/w3c/csswg-drafts/issues/11788
19:03:19 <ccameron> ccameron has joined #css
19:03:56 <ChrisL> topic: https://github.com/w3c/csswg-drafts/issues/11788
19:04:12 <ChrisL> github: https://github.com/w3c/csswg-drafts/issues/11788
19:04:59 <ChrisL> ccameron: this is to avoid a divide by zero
19:05:18 <ccameron> the epsilon should only be used to color match (very exactly) with an image
19:05:24 <Said> Said has joined #CSS
19:05:28 <ccameron> this feature is good enough without eps
19:06:03 <ccameron> it's purely numerical
19:06:13 <ccameron> can set to like 0.5 even
19:06:58 <ccameron> the epsilon value is in the gain application color space (which is linear, and is either "base image" primaries or "alternate image" primaries)
19:06:58 <ccameron> in practice, that's sRGB, P3 or Rec2020 primaries
19:09:18 <ccameron> what's the gain application color space?
19:09:18 <ccameron> primaries of the first space specified is most "normal" default
19:10:43 <ChrisL> github: https://github.com/w3c/csswg-drafts/issues/11787
19:12:49 <ChrisL> RESOLVED: require strict inequality for H1 and H2
19:13:21 <ChrisL> github: https://github.com/w3c/csswg-drafts/issues/11694
19:14:31 <ChrisL> Most edits done, need to discuss about allowing a single value or not
19:14:46 <ChrisL> agenda is https://lists.w3.org/Archives/Member/w3c-css-wg/2025AprJun/0002.html
19:14:59 <ChrisL> WPT allows single value
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19:15:46 <ChrisL> agenda is https://lists.w3.org/Archives/Member/w3c-css-wg/2025AprJun/0002.html
19:16:21 <ChrisL> RESOLUTION: allow single value, well defined
19:16:34 <ccameron> https://github.com/w3c/csswg-drafts/issues/11558
19:16:43 <jyasskin> topic: https://github.com/w3c/csswg-drafts/issues/11558
19:17:14 <ChrisL> github: https://github.com/w3c/csswg-drafts/issues/11558
19:18:15 <jyasskin> ccameron: We probably won't agree on the default value. Having auto be browser-chosen and map to a single value .. maybe it's start on one state, and we'll eventually agree on something and be able to standardize that.
19:18:46 <jyasskin> ccameron: But I think I can't change several years of Chrome behavior, and good HDR doesn't need reduction, and the concern that HDR content will get mastered poorly if constrained by default.
19:19:12 <ChrisL> present+ simon, christopher, said, jeffrey
19:19:33 <jyasskin> ccameron: I think we should have auto do what the browser wants, and provide the signal that the user left the default instead of explicitly asking for one of the options. Is that reasonable?
19:20:15 <jyasskin> simon: Apple doesn't hav etoo much information. We want auto to be uniform for all elements. Ideally we don't want images+videos to have different behavior if 'auto' is applied to both, but we have historical behavior we might have to support.
19:20:44 <jyasskin> simon: Can't commit that auto will be the same for all elements. Don't want heuristics ... might decide full-screen will allow full HDR.
19:20:58 <jyasskin> simon: Don't plan any in-page heuristics like "image is next to text".
19:21:20 <jyasskin> simon: Question about HDR-css colors vs HDR images & video: are we agreed that the dynamic-range-limit property affects both box decorations and content?
19:21:23 <jyasskin> <yes>
19:21:49 <jyasskin> ChrisL: We don't have syntax, and we're waiting for someone to do it, but we intend it to affect everything. If you want a particular thing, you should select it.
19:22:11 <jyasskin> simon: We do have a bug, but that's a bug. When people start specifying these colors, people might want to specify colors and replaced content separately.
19:22:28 <jyasskin> ccameron: Can specify different  colors for different elements.
19:22:52 <jyasskin> simon: Videos have internal controls (??) which might want different color limits.
19:23:06 <jyasskin> ChrisL: I'm writing some tests.
19:23:40 <jyasskin> ChrisL: WPT is SDR & sRGB-only, but you can still test color mapping. Don't know how you'll get a headroom value.
19:24:17 <jyasskin> ChrisL: Does Apple have concerns?
19:24:37 <jyasskin> simon: Haven't digested the spec enough. Any concerns would be in terms of how HDR colors coexist with other content. To prevent annoying use.
19:25:36 <ccameron> proposed resolution: add "auto" value, which maps to browser-defined value (1 of the 3)
19:26:04 <jyasskin> ccameron: Suggest we sleep on this.
19:26:40 <jyasskin> simon: Think I'm ok resolving to add an 'auto' value, but not ready to say exactly how it behaves. Not ready to say it applies equally to images and video.
19:27:13 <jyasskin> github-bot: end topic
19:28:00 <ChrisL> topic: close
19:28:12 <ChrisL> rrsagent, make minutes
19:28:14 <RRSAgent> I have made the request to generate https://www.w3.org/2025/04/09-css-minutes.html ChrisL
19:28:44 <ChrisL> Meeting: HDR Breakout
19:28:51 <ChrisL> Chair: ChrisL
19:28:56 <ChrisL> rrsagent, make minutes
19:28:57 <RRSAgent> I have made the request to generate https://www.w3.org/2025/04/09-css-minutes.html ChrisL
19:29:43 <jyasskin> ChrisL: I think you'll need to clean up the minutes comment in https://github.com/w3c/csswg-drafts/issues/11694#issuecomment-2790760847. It's got logs for all 3 issues because the right command is 'topic:' instead of 'github:'.
19:33:20 <astearns> Finally back after more than four hours from a two-hour task. Sorry to have missed everyone. Thanks ChrisL for standing in for me and apologies for the late notice
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