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Microsoft's vertical-align: sub test and vertical-align: super test

From: Gérard Talbot <css21testsuite@gtalbot.org>
Date: Mon, 15 Feb 2010 13:13:25 -0800
Message-ID: <fdc965a29057869b249bb38c9f13b919.squirrel@cp3.shieldhost.com>
To: "public-css-testsuite@w3.org" <public-css-testsuite@w3.org>
Cc: "Arron Eicholz" <Arron.Eicholz@microsoft.com>
Hello all,

http://www.w3.org/Style/CSS/Test/CSS2.1/20100127/html4/vertical-align-115.htm

http://test.csswg.org/source/contributors/microsoft/submitted/Chapter_10/vertical-align-115.xht

Those 2 tests assume that vertical-align: sub should be 4 pixels below
the baseline when Ahem font with a font-size of 48px is used. You will
find no such requirements in CSS 2.1 (regarding vertical-align: sub) and
no such typography definition in Ahem font. So, this test is based on a
purely arbitrary value and can not be accepted.

{
sub
    Lower the baseline of the box to the proper position for subscripts
of the parent's box. (This value has no effect on the font size of
the element's text.)
super
    Raise the baseline of the box to the proper position for
superscripts of the parent's box. (This value has no effect on the
font size of the element's text.)
}
coming from
http://www.w3.org/TR/CSS21/visudet.html#propdef-vertical-align

"proper position for subscripts" does not necessarly mean 4px or 6px or
8px for Ahem when base font-size is 48px.

Firefox 3.6 will position the sub line to 6 pixels below the baseline 
when Ahem font with a font-size of 48px is used and will therefore
display a thin red line in those tests.

Safari 4.0.4 will position the sub line to 8 pixels below the baseline 
when Ahem font with a font-size of 48px is used and will therefore
display a 4px thick red line in those tests.

vertical-align: super tests also involve an arbitrary offset value above
the baseline or above the x-height line.

http://test.csswg.org/source/contributors/microsoft/submitted/Chapter_10/vertical-align-116.xht

http://www.w3.org/Style/CSS/Test/CSS2.1/20100127/html4/vertical-align-116.htm

are even worse as it involves fraction of a pixel: 0.6in * 96px/in = 57.6px

I suggest something like

https://bug192077.bugzilla.mozilla.org/attachment.cgi?id=125662

or

http://www.gtalbot.org/DHTMLSection/vertical-align-values.html

with a big font-size value and with x, p, É characters and with
reasonable examples. Other testcase replacements are possible too.

But as it is, those vertical-align-115 and vertical-align-116 can not be
acceptable.

regards, Gérard
-- 
Contributions to the CSS 2.1 test suite:
http://www.gtalbot.org/BrowserBugsSection/css21testsuite/

CSS 2.1 test suite (alpha 1; January 27th 2010):
http://www.w3.org/Style/CSS/Test/CSS2.1/20100127/html4/toc.htm

CSS 2.1 test suite contributors:
http://test.csswg.org/source/contributors/
Received on Monday, 15 February 2010 21:14:00 GMT

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