[css-sizing] Define a term like "uses fit-content inline sizing" (like floats)

[zcorpan]

For whatwg/html#4143 I tried to define that buttons size in the inline direction like floats do, i.e. "shink-to-fit" (CSS 2.2 terminology) or "shrink-wrap" (HTML used this terminology until I changed it in that PR now), if the inline-size is auto.

It seems reasonable to define a term that means exactly this, that can be used by floats, abspos, buttons, legends, and whatever else uses this behavior.

In IRC, @dbaron said

I think it would be reasonable to define the term as "uses fit-content inline sizing" or something like that. (It's also nice when the term matches a name in author-exposed syntax like fit-content.)

[fantasai]

I think you can just say that for a button that's a block or inline block, the used value of auto on the inline-size property is fit-content.

[fantasai]

Or maybe, more accurately, “behaves as” fit-content. I'm guessing for Web-compat we can't actually set it that way in CSS. :)

[fantasai]

(Sorry, accidentally hit the close button earlier.)

[fantasai]

Oh! I just remembered that we added a term for handling cases like this: just say “In the inline axis, the automatic size is the fit-content size.” https://drafts.csswg.org/css-sizing-3/#automatic-size