W3C home > Mailing lists > Public > www-style@w3.org > October 2010

Re: aspect-ratio property

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Wed, 6 Oct 2010 13:16:25 -0700
Message-ID: <AANLkTimxdv7ZthU4aAUFydfwTq+3Aop2-kYQuu3nHX9Z@mail.gmail.com>
To: www-style list <www-style@w3.org>
On Wed, Oct 6, 2010 at 11:43 AM, Tab Atkins Jr. <jackalmage@gmail.com> wrote:
> So, we talked about aspect-ratio a little while ago.  There was
> general agreement that it sounded like a pretty cool idea, but then
> nobody took it farther, probably because it doesn't have a good home,
> seeing as Box Model 3 is dead at the moment.
> I've taken the liberty of drafting up a spec for it, for discussion
> and possible later incorporation into another module -
> <http://www.xanthir.com/:cz9>.
> I don't have the language quite right yet, I know.  I want to disallow
> it on table* elements right now, because resolution of it should be up
> to the table-layout algo in play.  Generally, I just want it only
> defined on things in static or positioned flow.  How do I phrase it
> correctly to state that?  I also need to expand my definition of
> "underspecified" to properly handle positioned elements, where
> left/right/top/bottom comes into play as well.

I've updated my draft with better language to handle abspos elements as well:

The `aspect-ratio` property controls the resolution of underspecified
values for the `width` and `height` properties of elements in CSS,
such that the ratio of the width and height is a specific value.

For elements in static flow, `width` and `height` are underspecified
if the computed values of `width`/`height` for the element are `auto`,
and the used width/height of the element is not currently being
restricted by the `min-width`, `max-width`, `min-height`, or
`max-height` properties.  For absolutely positioned elements, `width`
is underspecified if the computed value for `width` on the element is
`auto` and the computed values of `left` or `right` are `auto`;
`height` is underspecified if the computed value for `height` on the
element is `auto` and the computed values of `top` or `bottom` are

I believe this is correct.

The term "static flow" is undefined.  Is there currently a good term
to describe it in CSS?  By that I mean "positioning governed by the
default layout model of CSS, rather than by Positioning, Table Layout,
or another alternative layout mode".

Received on Wednesday, 6 October 2010 20:17:19 UTC

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