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Re: [css3-transitions][css3-values] transition-duration's inital value is '0' without a unit

From: Brad Kemper <brad.kemper@gmail.com>
Date: Fri, 22 Oct 2010 23:20:33 -0700
Cc: "L. David Baron" <dbaron@dbaron.org>, www-style list <www-style@w3.org>
Message-Id: <01ACB325-9A25-43B8-8573-E23558900F83@gmail.com>
To: Sylvain Galineau <sylvaing@microsoft.com>

On Oct 22, 2010, at 7:35 PM, Sylvain Galineau wrote:

>> From: L. David Baron [mailto:dbaron@dbaron.org]
>> Sent: Friday, October 22, 2010 7:06 PM
>> To: Sylvain Galineau
>> Cc: www-style list
>> Subject: Re: [css3-transitions][css3-values] transition-duration's
>> inital value is '0' without a unit
>> On Friday 2010-10-22 23:40 +0000, Sylvain Galineau wrote:
>>> So either the former picks a unit or we extend the optional-unit-for-
>> zero exception of <length>
>>> to times for consistency. Although in the latter case it would seem
>> coherent to do the same for
>>> frequencies and angles as well. It's the bigger change but I lean
>> towards the latter. It'd be
>>> odd if width:0 was valid but not transition-duration:0 or
>> transform:rotate(0). (Although that
>>> ship may already have sailed, implementation-wise...).
>> The gradient syntax depends on unitless zero not being allowed for
>> angles.  See the thread starting with
>> http://lists.w3.org/Archives/Public/www-style/2009Nov/0043.html .  I
>> believe we agreed on that at some point following the thread, though
>> I'm not sure.
> OK.
> 1. For <time> and transition-duration, both Firefox 4b6 and Chrome 7 return "0s". Can
> we simply make this the initial value for transition-duration in the spec ?
> 2. For <angle>, my bad: I forgot that this would most likely always require a unit. 
> The decision here seems to be whether existing transform implementations are wrong
> or make an exception for them.
> 3. For <frequency>, do we make 0 <frequency> unitless.
> Given the gradient issue, I am now a bit warier of making 0 values unit-less since
> it could cause ambiguity in the future. 

With my proposed change to the linear-gradient draft, unit-less 0 for the angle is unambiguous. 
Received on Saturday, 23 October 2010 06:21:03 UTC

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