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[css3-multicol] contradictions about whether zero is allowed for 'column-width'

From: L. David Baron <dbaron@dbaron.org>
Date: Mon, 16 May 2011 14:41:28 +0200
To: www-style@w3.org
Message-ID: <20110516124128.GA2936@pickering.dbaron.org>
http://dev.w3.org/csswg/css3-multicol/#cw seems to give two
different answers as to whether zero is a legal value for
column-width:
  # Computed value: the absolute length, zero or larger 
and then:
  # Specified values must be greater than 0.

I feel quite strongly that zero should be allowed, because I'm
strongly opposed to CSS having any value range restrictions that
require an open range (i.e., one where the endpoints are not
allowed).

I think open ranges are a problem both because:

 (1) They seem likely to lead to interoperability problems if people
 want to try to get the "minimal value", since rounding may vary
 between implementations.

 (2) We have multiple features that require clamping values to the
 allowed range:
   (a) calc()
   (b) interpolation in transitions or animations, when the
       cubic-bezier() timing function has Y1 or Y2 values outside of
       the 0-1 range.
 and clamping to an open range does not make sense.  Sensible
 clamping requires a closed range.

So I think either '0' needs to be allowed or, if that makes the
algorithm nonsensical, the range restriction needs to be changed to
start at some other value.

-David

-- 
L. David Baron                                 http://dbaron.org/
Mozilla Corporation                       http://www.mozilla.com/
Received on Monday, 16 May 2011 12:41:54 GMT

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