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

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

From: Håkon Wium Lie <howcome@opera.com>
Date: Wed, 9 Jun 2010 00:18:29 +0200
Message-ID: <19470.49589.408933.743362@gargle.gargle.HOWL>
To: MURAKAMI Shinyu <murakami@antenna.co.jp>
Cc: Hakon Wium Lie <howcome@opera.com>, "Tab Atkins Jr." <jackalmage@gmail.com>, John Daggett <jdaggett@mozilla.com>, Boris Zbarsky <bzbarsky@mit.edu>, www-style list <www-style@w3.org>
Also sprach MURAKAMI Shinyu:

 > > You can use 3) and 4) to write a default style sheet. E.g.:
 > > 
 > >   h1:lrt, h1:rtl { font-size: 2em; margin: .67em 0 }
 > >   h1:ttb { font-size: 2em; margin: 0 .67em }
 > 
 > >   dir:lrt   horizontal writing is supported and @dir has been set to 'lrt'
 > >   dir:rtl   horizontal writing is supported and @dir has been set to 'rtl'
 > >   dir:ttb   vertial writing is supported and the initial value of
 > >             'writing-mode' is 'tb-rl'
 > 
 > See the following example:
 > 
 >   table { writing-mode: lr-tb }
 >   ...
 >   <h1>...</h1>
 >   <table>
 >       ...
 >       <h1>...</h1>
 >       ...
 >   </table>
 > 
 > When the initial value of 'writing-mode' is 'tb-rl', the h1:ttb
 > {margin: 0 .67em} is used. It is ok for the first h1,
 > but the second h1 inside the table, same h1:ttb {margin: 0 .67em}
 > is used although the writing mode is changed.
 > The results will be miserable.

You just have to provide the values you prefer when switching
directions. E.g.:

  table { writing-mode: lr-tb }
  table h1, table h2 { margin: ... }

Anyway, the values provided in the default style sheet would probably
not be correct when switching writing modes. Even in my
horizonatal-only world, I tend to start my style sheets with these
lines of code:

  h1, h2, h3, ul, ol, dl, li, blockquote { margin: 0; padding: 0; border: none }

just to cleanse the palate. From there, one can easily specify the
preferred values.

 > Another case, when the initial value of 'writing-mode' is 'lr-tb'
 > and {writing-mode: tb-rl} is specified in the author style sheet,
 > we expect :ttb { ... } of the default style sheet is enabled,
 > but the :ttb selector is not affected by the real writing-mode.

Correct. Because we cannot make selectors depend on the value of
properties. We could make things more automatic if we added a "ttb"
value on @dir or some other hint about the preferred direction. But
you seem to think this is not a good idea?

-h&kon
              Håkon Wium Lie                          CTO °þe®ª
howcome@opera.com                  http://people.opera.com/howcome
Received on Tuesday, 8 June 2010 22:19:19 GMT

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