- From: Rik Cabanier via GitHub <sysbot+gh@w3.org>
- Date: Mon, 29 Nov 2021 21:59:59 +0000
- To: public-fxtf-archive@w3.org
> Over in [this issue](https://github.com/w3c/ColorWeb-CG/issues/65), a very similar issue came up, and at least with respect to RGB (ignoring A for the moment), the general idea is that color values shouldn't be clamped, and should be allowed to express colors of any gamut. The compositor will, at the end, clamp the colors to the gamut of the display, and to the SDR range. For "regular" drawing, color should be clamped to a valid range. Going outside that (ie with ICC color) will no longer result in accurate color rendering. Also, the compositor doesn't clamp to the gamut. It should render in (or receive pixels of) the output colorspace. > With respect to HDR, I do feel that the best thing to do is to specify "we will clamp to SDR unless something is explicitly specified using some yet-to-be-defined API". I think that is reasonable. We would have to define what to clamp to though. > To open the HDR bikeshed doors a bit ... my sense is that we will eventually want to add a spec that allows an individual element to explicitly enable HDR for-just-that-element. When enabling HDR, it can specify what kind of HDR is desired (just-extended-values, or treat-as-HLG, or treat-as-extended-with-metadata-sort-of-like-PQ). I don't quite understand how that would work with a single element. You always want to render a group of graphics to a single colorspace. > [This proposal](https://github.com/w3c/ColorWeb-CG/blob/master/hdr_html_canvas_element.md) discusses adding HDR to canvas elements. This is also similar to specifying a "working interpolation space" for an element. ([This issue](https://github.com/w3c/ColorWeb-CG/issues/64) discusses whether or not that "working pixel buffer space" should be independent of the "HDR type of space for compositing the element" but ... that's a whole nother bike shed). The status of that spec is "we need to write a prototype so people can feel their way around what is best". Adobe applications have the "working colorspace" which is the colorspace that compositing takes place in and the "target colorspace" which is the one of the device. Typically they are the same but some workflows and placed content (ie PDF) allow them to be different. In the case of the web, iframes and canvas would be similar. -- GitHub Notification of comment by cabanier Please view or discuss this issue at https://github.com/w3c/fxtf-drafts/issues/446#issuecomment-982061967 using your GitHub account -- Sent via github-notify-ml as configured in https://github.com/w3c/github-notify-ml-config
Received on Monday, 29 November 2021 22:00:01 UTC