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[nightly-unstable] font-size-118 : 'font-size: smaller' applied with a parent with 'font-size: 160px': impossible to predict

From: Gérard Talbot <css21testsuite@gtalbot.org>
Date: Sat, 11 Feb 2012 23:33:10 -0500
Message-ID: <1de99a9e27c0250a9e1a261974a952a6.squirrel@ed-sh-cp3.entirelydigital.com>
To: "Public CSS test suite mailing list" <public-css-testsuite@w3.org>


line 15  .big { font-size: 10em; }

line 17  .smaller { font-size: smaller; }

line 28    <div class="big"><div class="smaller"><div class="text">     

The CSS 2.1 spec [1] does not specify the scaling factor involved for
'smaller' and 'larger' keywords. So, if computed font-size of .big node
is 160px, then computed font-size of .smaller could be almost any value
(lower than 160px). This gives leeway, leniency, laxism.

Browsers  : computed value for .smaller
--------    ---------------------------
Firefox 10:   106.667px (meaning a scaling factor of 1.5)
Chrome 17 :   133px     (meaning a scaling factor of 1.2)
Opera 11.6:   128px     (meaning a scaling factor of 1.25)
(I have not tested with IE8 nor IE9).

Note that .big computed font-size is already outside the table of

So, for all those reasons, I am not sure this test is good. Its layout
rendering is definitely *not* predictable: the dimensions of the filled
green rectangle is unpredictable.

In CSS1, the suggested scaling factor between adjacent indexes was 1.5,
which user experience proved to be too large. In CSS2, the suggested
scaling factor for a computer screen between adjacent indexes was 1.2,
which still created issues for the small sizes. Implementation
experience has demonstrated that a fixed ratio between adjacent
absolute-size keywords is problematic, and this specification does not
recommend such a fixed ratio.

Contributions to the CSS 2.1 test suite:

CSS 2.1 Test suite RC6, March 23rd 2011:

CSS 2.1 test suite harness:

Contributing to to CSS 2.1 test suite:
Received on Sunday, 12 February 2012 04:33:39 UTC

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