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CSS 2 font-size clarification.

From: Richard York <richy@smilingsouls.net>
Date: Fri, 23 Jul 2004 03:15:31 -0500
Message-ID: <4100C923.1000404@smilingsouls.net>
To: www-style@w3.org

I have a question concerning the use of absolute size keywords for the 
font-size property.

CSS 2 recommends:
"On a computer screen a scaling factor of 1.2 is suggested between 
adjacent indexes; if the 'medium' font is 12pt, the 'large' font could 
be 14.4pt. Different media may need different scaling factors. Also, the 
user agent should take the quality and availability of fonts into 
account when computing the table. The table may be different from one 
font family to another."

So there's a vague suggestion that the medium keyword equates a 12pt 
size, though this language appears to only be a "for instance", in my 
test cases this appears consistent with actual UA implementation.

Opera 7.5, IE 6 and Moz appear to have this interpretation:
h1 == 24pt == xx-large
h2 == 18pt == x-large
h3 == 14pt == large
h4 == 12pt == medium
h5 == 10pt == small
h6 == 8pt  == x-small
       7pt  == xx-small

The test case doesn't show a visually noticable difference in the 
rendering of each heading, its corresponding point size and absolute 
keyword.

To get down to my questions.. in CSS 2.1 and 3 apparently a new scaling 
factor was necessary, however, there appears to be no suggested starting 
point (or example) as there was in CSS 2, with the language:

"if the 'medium' font is 12pt"

Though vague as it was it appeared that UAs used it, which resulted in 
consistent behavior, whether intentionally or not. (at least as far as 
Windows UAs are concerned, I haven't yet tested on other OSs).

What was the reason for the elimination of this language? Secondly since 
  in this case there appears to be a consistent behavior between UAs, 
why was the spec changed at all? Why not just add more keywords to 
preserve BC with the existing implementations?

Forgive my ignorance.. I'm trying to present the material for a book, so 
I need a good understanding of what led to the change and what effects, 
if any, the change will have. The biggest thing that sticks out to me is 
that under CSS 2 the <h6> heading equates to the x-small keyword, 
whereas its xx-small under CSS 2.1 and 3.

Thanks!

Regards,
Richard York

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Received on Friday, 23 July 2004 04:15:51 GMT

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