Color Spaces: Track CSS debates about gamut-mapping

[mirisuzanne]

As I understand the primary issue: out-of-gamut canvas colors are currently clipped, so it could be a problem if CSS colors don't match canvas colors. But I don't see a clear resolution on that yet, or much discussion since August. We'll want to track the changes being made here, and make sure we're shipping something compatible with browsers. The two issues I was able to find in the CSSWG repo related to gamut mapping are:

• [css-color-4] Disagreements over gamut mapping w3c/csswg-drafts#7610
• [css-color-4] CSS gamut mapping algorithm clarifications w3c/csswg-drafts#7653

[mirisuzanne]

It looks like CSS/browsers are punting on the specifics of gamut-mapping, by ensuring that it's not needed internally for color math - and will only be applied to used-values for display.

On our end, though - a gamut-mapping function would make it much easier for authors to handle legacy fallback behavior. I don't think we can punt on the details of that. That's useful even if it doesn't match a CSS function exactly - though it would be good if we can mach CSS in the future. Not sure what the right approach here is.

[mirisuzanne]

• add to-gamut to summary
• add design decision note about not requiring algo at this point

[svgeesus]

Also

• [css-color-4] CSS gamut mapping algorithm clarifications w3c/csswg-drafts#7653