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Re: scientific notation text confusing

From: Chris Lilley <chris@w3.org>
Date: Fri, 26 Jan 2007 16:28:01 +0100
Message-ID: <114644897.20070126162801@w3.org>
To: "Robert Longson" <longsonr@gmail.com>
Cc: www-svg@w3.org

On Friday, January 26, 2007, 2:41:18 PM, Robert wrote:

RL> Hello,
RL>   
RL>  http://www.w3.org/TR/SVG/types.html#DataTypeLength says:
RL>   
RL>  "The specification of real number values is different for
RL> property values than for XML attribute values." 
RL>   
RL>  It then goes on to talk about CSS2 and XML Attributes in two bullet points.
RL>   
RL>  According to http://www.w3.org/TR/SVG/intro.html#TermProperty
RL> the term property applies to both XML attributes and CSS values as
RL> defined in  http://www.w3.org/TR/SVG/propidx.html.

Yes, properties can be expressed as formatting attributes (In SVG
Tiny, thats the only way) or in CSS stylesheets. Note that some
properties are shared with XSL.

RL> So should the quoted sentence actually say: "The specification of
RL> real number values is different for CSS2 property values than for
RL> XML attribute values."

Useful suggestion. We will add that to the errata.

All properties can also be expressed as attributes; but properties can
also be expressed in stylesheets (not in Tiny, but in other versions
that are supersets of Tiny) - external style sheets, style elements,
and the style attribute.


Its clear that in a CSS stylesheet, you can't say for example

 font-size: 8.2e-6

since scientific notation is forbidden in CSS (the SVG WG did ask CSS
WG to add it; they declined to do so) thus you have to say

  font-size: 0.0000082

and in fact for a CSS stylesheet you also need to provide units there
as well

  font-size: 0.0000082px

despite the non-intuitive result that this may (due to scaling)
actually render at, say, 10 device pixels high :)
  
RL>  to create a clearer mapping between this sentence and the
RL> two subsequent bullet points.

Thanks for your comment, we will try to express this more clearly in
the spec, incorporating your suggested wording.


-- 
 Chris Lilley                    mailto:chris@w3.org
 Interaction Domain Leader
 Co-Chair, W3C SVG Working Group
 W3C Graphics Activity Lead
 Co-Chair, W3C Hypertext CG
Received on Friday, 26 January 2007 15:28:12 GMT

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