[csswg-drafts] computed value rules for 'overflow' should not depend on whether something is a replaced element (#7435)

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

== computed value rules for 'overflow' should not depend on whether something is a replaced element ==
css-overflow-3 [states rules](https://drafts.csswg.org/css-overflow-3/#overflow-properties) for determining the computed value of the `overflow` property that depend on whether something is a replaced element:

> On non-[replaced](https://drafts.csswg.org/css-display-3/#replaced-element) elements, the [visible](https://drafts.csswg.org/css-overflow-3/#valdef-overflow-visible)/[clip](https://drafts.csswg.org/css-overflow-3/#valdef-overflow-clip) values of [overflow](https://drafts.csswg.org/css-overflow-3/#propdef-overflow) compute to [auto](https://drafts.csswg.org/css-overflow-3/#valdef-overflow-auto)/[hidden](https://drafts.csswg.org/css-overflow-3/#valdef-overflow-hidden) (respectively) if one of [overflow-x](https://drafts.csswg.org/css-overflow-3/#propdef-overflow-x) or [overflow-y](https://drafts.csswg.org/css-overflow-3/#propdef-overflow-y) is neither visible nor clip.
>
> On [replaced elements](https://drafts.csswg.org/css-display-3/#replaced-element), all values other than [visible](https://drafts.csswg.org/css-overflow-3/#valdef-overflow-visible) compute to [clip](https://drafts.csswg.org/css-overflow-3/#valdef-overflow-clip).

I didn't think computed values could depend on whether something is a replaced element; I don't think that's known at value computation time (e.g., for `<object>`).

If that's the case, I'd suggest that the non-replaced rule above apply to all elements, and then the replaced rule be handled at used value time.  (This is a behavior change in the behavior of combinations of `visible` on one axis with a value other than `visible` or `clip` on the other axis.  However, I suspect that behavior matches implementations today (at least Gecko's), in so far as the difference in behavior on replaced elements is observable.)

(Noticed while trying to write edits for #6212.)

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/7435 using your GitHub account


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

Received on Thursday, 30 June 2022 00:40:52 UTC