- From: CSS Meeting Bot via GitHub <sysbot+gh@w3.org>
- Date: Wed, 20 Apr 2022 16:38:30 +0000
- To: public-css-archive@w3.org
The CSS Working Group just discussed `[css-color] [filter-effects] Should no-op filters produce different output from no filter?`. <details><summary>The full IRC log of that discussion</summary> <fantasai> topic: [css-color] [filter-effects] Should no-op filters produce different output from no filter?<br> <fantasai> github: [css-color] [filter-effects] Should no-op filters produce different output from no filter?<br> <fantasai> github: https://github.com/w3c/csswg-drafts/issues/7100<br> <fantasai> smfr: Issue here is that CSS filters are specified to use sRGB as their color interpolation model<br> <chris> they use linear-light sRGB<br> <fantasai> smfr: This is a problem when authors apply filters to colors outside of sRGB gamut<br> <fantasai> smfr: e.g. display-p3 or color specified with LCH color space<br> <chris> q+<br> <fantasai> smfr: This is important because often authors will apply no-op filters, with intent to animate later<br> <fantasai> smfr: This means such filters will flatten the colors<br> <fantasai> smfr: In testing, looked like Chrome isn't doing this: they allow out-of-sRGB colors through filters<br> <fantasai> smfr: WebKit does limit colors to sRGB<br> <fantasai> smfr: Don't think this is desriable<br> <fantasai> smfr: One, I think authors expect no-op filters to not have an effect<br> <fantasai> smfr: And second as an implementer, I'd like to optimize away such filters by not doing anything special<br> <fantasai> smfr: Since CSS specifies sRGB compositing and filters are specified to do this also<br> <fantasai> smfr: CSS uses non-linear sRGB<br> <fantasai> smfr: so I'm not sure how to resolve this, because I don't think we specify our color compositing model in a way that matches browsers<br> <Rossen_> q<br> <fantasai> smfr: maybe Chris has an opinion<br> <fantasai> chris: Correct that filters use sRGB and clamp at each stage in the pipeline<br> <Rossen_> ack chris<br> <fantasai> chris: They do use linear-light sRGB<br> <fantasai> chris: They don't use gamut-?? values<br> <fantasai> chris: Very obvious when you're doing it wrong<br> <smfr> s/gamut-??/gamut-encoded/<br> <fantasai> chris: I suggested a way forward for this, beefing up filters to have a wider color gamut<br> <fantasai> chris: Simon said very nice, but doesn't solve my issue which is no-op filter<br> <fantasai> chris: My concern about is that as soon as someone starts to animate, from 0 to 0.01, then there's a sudden change<br> <fantasai> chris: I can see that it would help with no-op filters, but not with an animation case<br> <fantasai> smfr: That's very true, and that's why I think we need to specify that CSS filters interpolate in the working color space, so that they don't truncate colors?<br> <fantasai> chris: The concept of a working color space isn't well-defined<br> <fantasai> chris: we have different ones for different operations<br> <fantasai> chris: Talkinga bout compositing, but not just compositing, it's also the convesion from luminance or conversion from saturation, all use constants from sRGB and not display-p3<br> <fantasai> chris: need to fix that, and the way to fix that is to continue using sRGB ones, and because in linear-light make them extended, and in that way can represent all other colors as well<br> <fantasai> chris: I think that's the best minimal change, otherwise you have [problems]<br> <fantasai> smfr: That would be fine...<br> <Rossen_> q?<br> <fantasai> chris: If we can bash this out, would be great<br> <fantasai> smfr: Would be interested in hearing from Chromium and Gecko, what their filter color space is<br> <fantasai> chrishtr: I'll have to check<br> <fantasai> emilio: same here<br> <fantasai> emilio: but pretty sure we have code to optimize away no-op filters<br> <fantasai> Rossen_: so, do more investigation on Chrome and Gecko side and then come back to this?<br> <fantasai> chris, smfr: sounds fine<br> <chrishtr> will investigate<br> </details> -- GitHub Notification of comment by css-meeting-bot Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/7100#issuecomment-1104151454 using your GitHub account -- Sent via github-notify-ml as configured in https://github.com/w3c/github-notify-ml-config
Received on Wednesday, 20 April 2022 16:38:32 UTC