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Re: [css3-text-layout] New editor's draft - margin-before/after/start/end etc.

From: Håkon Wium Lie <howcome@opera.com>
Date: Fri, 4 Jun 2010 11:23:19 +0200
Message-ID: <19464.50695.663164.207388@gargle.gargle.HOWL>
To: Boris Zbarsky <bzbarsky@mit.edu>
Cc: www-style list <www-style@w3.org>
Also sprach Boris Zbarsky:

 > > You should be able to forget about it when the value of 'writing-mode'
 > > is known for all elements, I believe.
 > 
 > There is no such point if scripting is allowed in a document, since 
 > script can add new elements, right?

Right, when scripting is supported you need to keep them around.

 > > In the specs, the "specified value" is not tied to style rules.
 > > Rather, for every property/element combination there is a
 > > specified value.
 > >
 > >    http://dev.w3.org/csswg/css3-cascade/
 > >    http://www.w3.org/TR/CSS2/cascade.html#specified-value
 > 
 > OK, fair.  The spec doesn't seem to have a good way to talk about the 
 > actual values in declarations....

Perhaps we could use "declared value"?

 > > And for the properties in question ('direction' and 'block-flow',
 > > which 'writing-mode' is a shorthand for) the specified value is the
 > > same as the computed value.
 > >
 > >    http://dev.w3.org/csswg/css3-text-layout/#direction
 > >    http://dev.w3.org/csswg/css3-text-layout/#block-flow
 > 
 > Right, and by this definition of "specified value" the value depends on 
 > the rules applied to the element and the parent of the element, right 
 > (think "writing-mode:inherit").

Yes.

 > > I think one should convert DDAs before they turn into specfied values.
 > > That is, DDAs should not have specified values -- only properties that
 > > also have computed/used/actual values should have specified values.
 > 
 > OK.  Given the definition of "specified value" in CSS2.1, that seems 
 > reasonable.
 > 
 > Note that currently there is no DOM API for accessing specified values 
 > in that sense.  There's an API for accessing declarations, and an API 
 > for accessing computed/used (sort of a mix) values, right?

I don't have the full overview of the DOM APIs. It would be helpful if
someone could provide the list of APIs and how they tie into CSS
values at various stages.

 > > Something like: "if a property has an alias, resolve it and let it
 > > fight its way through cascading...". Hmm.
 > 
 > You can't resolve before cascading, can you?  Or rather, you can't 
 > resolve before you have cascaded and maybe-inherited writing-mode.

Yes, 'writing-mode' must be processed to specified value before the
DDAs can be cascaded. That's an unhealthy inter-dependency between
properties, it seems.

-h&kon
              Håkon Wium Lie                          CTO °þe®ª
howcome@opera.com                  http://people.opera.com/howcome
Received on Friday, 4 June 2010 09:24:07 GMT

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