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[CSS21] Cascade of SVG presentational attributes

From: fantasai <fantasai.lists@inkedblade.net>
Date: Thu, 17 Jun 2010 13:49:11 -0700
Message-ID: <4C1A8A47.6060203@inkedblade.net>
To: "www-style@w3.org" <www-style@w3.org>, www-svg <www-svg@w3.org>
It was pointed out to me during an FXTF telecon that the CSS2.1 spec
conflicts with SVG in section "6.4.4 Precedence of non-CSS presentational
hints", specifically this section:

   # For other languages, all document language-based styling should
   # be handled in the user agent style sheet.
                  -- http://www.w3.org/TR/CSS21/cascade.html#preshint

Wrt cascading, the SVG spec says the following:

   # For user agents that support CSS, the presentation attributes must
   # be translated to corresponding CSS style rules according to rules
   # described in Precedence of non-CSS presentational hints  ([CSS2],
   # section 6.4.4), with the additional clarification that the
   # presentation attributes are conceptually inserted into a new author
   # style sheet which is the first in the author style sheet collection.
   # The presentation attributes thus will participate in the CSS2
   # cascade as if they were replaced by corresponding CSS style rules
   # placed at the start of the author style sheet with a specificity
   # of zero. In general, this means that the presentation attributes
   # have lower priority than other CSS style rules specified in author
   # style sheets or ‘style’  attributes.
   -- http://dev.w3.org/SVG/profiles/1.1F2/publish/styling.html#UsingPresentationAttributes

To make this section of CSS2.1 more SVG-friendly, I suggest rewriting
6.4.4 as follows:

   | For other languages, all document language-based styling must
   | be translated to the corresponding CSS and either enter the cascade
   | at the user agent level or, as with HTML presentational hints,
   | be treated as author level rules with a specificity of zero
   | placed at the start of the author style sheet.

Then SVG or other specs can simply write something like
   | ... presentational attributes are treated as author-level rules
   | according to the rules described in Precedence of non-CSS
   | presentational hints [CSS21:6.4.4]

~fantasai
Received on Thursday, 17 June 2010 20:49:45 GMT

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