Re: [csswg-drafts] [css-values-5] issues with interpolation rules for calc-size() (#10220)

One other issue with the rules is that they have frequent references to "the result’s [calc-size basis](https://drafts.csswg.org/css-values-5/#calc-size-basis)".  However, it's not clear to me whether this is intended to recursively extract the basis.  For example, can you interpolate between `calc-size(calc-size(min-content, size * 0.5), size * 0.5)` and `calc-size(min-content, size)`?

My understanding is the intent of allowing `calc-size()` values as the basis was to allow this sort of thing.  However, I think a literal reading of the spec currently doesn't allow it.

Then the question is:  if it is allowed, is the correct interpolation behavior to un-nest the `calc-size()` expression by substituting for the `size` in the outer expression's calculation, or is it to separately interpolate the calculation and the basis?  (The resulting behavior is different for the interpolation above:  with substitution the midpoint of the interpolation would be `calc-size(min-content, size * 0.625)` whereas with separate interpolation the midpoint would be `calc-size(calc-size(min-content, size * 0.75), size * 0.75)` which is equivalent to `calc-size(min-content, size * 0.5625)`.)

(I suppose one could ask the same question about the rules for interpolation when the basis is a `<calc-sum>`.)

-- 
GitHub Notification of comment by dbaron
Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/10220#issuecomment-2093178803 using your GitHub account


-- 
Sent via github-notify-ml as configured in https://github.com/w3c/github-notify-ml-config

Received on Friday, 3 May 2024 14:51:40 UTC