[css3-writing-modes] direction vs. writing mode in markup vs. style

Breaking the thread because this is an important distinction that
I think some people here are not getting.

On 10/24/2010 09:29 AM, David Hyatt wrote:
 >
 > Another idea: just specify writing-mode in HTML instead and don't have
 > it be in CSS at all (except as a pseudo class you match on in order to
 > provide rules for that writing mode).  This is a little weird in that
 > we already have direction in CSS though.

Two things:

a) Base directionality is a content property, not a styling property.
    The base directionality of an element is ultimately description of
    the content inside it and provides data that is critical to its
    correct layout no matter what styling (if any) is in use.

    (The 'direction' property does not actually belong in CSS: it exists
    in CSS in order to allow the HTML 'dir' attribute's functionality
    for raw XML documents. This use case probably should have been
    addressed with an xml:dir attribute rather than with CSS.)

    No author of an HTML document should be setting or resetting the
    base directionality of any elements via CSS: it should be set in
    the HTML, where it can be processed by non-CSS UAs and when author
    styles are disabled. [1]

b) The vertical/horizontal mode setting is not a content property, but
    a layout and stylistic one. It thus belongs in the styling layer,
    and not in the markup.

To me, any solution that scrambles this markup/style distinction is a
non-starter. So if this doesn't make sense to you, let's talk about it.

------

BTW, while I have your attention, the CSSWG's suggestion from the Oslo
F2F to use HTML's alternate style mechanism to address vertical vs.
horizontal styles has *already* been accepted by EPUB as the way forward
for addressing alternate style requirements. So let's please focus the
discussion on use cases that cannot be solved by this mechanism. [2]

Note also that EPUB has its own mechanism for handling unsupported
features, so that use case, while also applicable to CSS in general
and imo something we should address generally, is probably not urgent
for us to solve for them.

~fantasai

[1] More info on bidi markup vs. CSS:
        http://www.w3.org/International/questions/qa-bidi-css-markup

[2] Alternate style spec as proposed to EPUB:
       http://fantasai.inkedblade.net/style/specs/altss-tags/
     This will become an IDPF-track spec.

Received on Monday, 25 October 2010 07:12:05 UTC