[csswg-drafts] [css-display] Make 'flow-root' an independent keyword

Loirooriol has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-display] Make 'flow-root' an independent keyword ==
I have already found multiple people (myself included) confused because `display: block` and `display: inline` have the same inner display type, `flow`.

Making `flow-root` an inner display type overlaps with `flow`, and saying that `inline-block` has a `flow-root` inner display type is not intuitive and does not work well (#1246, #1486).

Additionally, there is the problem of adding layout containment to a ruby element (#1457). I think the obvious fix is making the principal box generated around the ruby container to become a block container (of the specified outer display type) and establish a BFC. But currently no `display` value allows this.

So I propose:

 - Make `flow-root` an independent keyword (similarly to `list-item`) which forces the element to "become a formatting context", i.e an inline box becomes an inline-block, a block container establishes its own BFC, and for ruby this applies to the principal box around the ruby container.

 - Restore the `block` inner display type from [2014 WD](https://www.w3.org/TR/2014/WD-css-display-3-20140911/#valdef-display-inside-block), rename `flow` to `auto`, let `auto` behave like `block` inner display type when block-level. To avoid name clashes, rename the outer display types to `inline-level` and `block-level`. That is, undo most part of https://lists.w3.org/Archives/Public/www-style/2015May/0098.html

So #1246 is solved as such: `inline-block` is syntactically equivalent to `inline-level block`, which behaves like `inline-level flow-root`. The difference is that, when blockified, the formers serializes to `block` (and may no longer establish a BFC) and the latter serializes to `flow-root` (and continues establishing a BFC). And the answer to #1486 is that the equivalence between `inline-block` and `inline-level block` is preserved, and the `flow-root`-ness is also preserved.

Letting an `auto` inner display type compute as `block` if the outer display type is `block-level` after possible blockifications or inlinifications also addresses #1341. You can use `display: block-level` (`block-level auto`) if you want a block box which inlinifies to `inline` (`inline-level auto`), or you can use `display: block` (`block-level block`) if you want a block box which inlinifies to `inline-block` (`inline-level block`).

See [my proposed specification](https://loirooriol.github.io/specs/css-display/) and the [bikeshed changes](https://github.com/Loirooriol/specs/blob/master/css-display/changes.diff).

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/1496 using your GitHub account

Received on Friday, 2 June 2017 19:42:05 UTC