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Re: [css3-transitions] transitions and rendering objects vs. DOM nodes

From: David Hyatt <hyatt@apple.com>
Date: Mon, 29 Jun 2009 10:13:14 -0500
Cc: robert@ocallahan.org, "L. David Baron" <dbaron@dbaron.org>, www-style@w3.org
Message-id: <0439D32D-3615-413E-AC8D-99D8FE28AB68@apple.com>
To: Giovanni Campagna <scampa.giovanni@gmail.com>
On Jun 29, 2009, at 9:29 AM, Giovanni Campagna wrote:

> 2009/6/29 David Hyatt <hyatt@apple.com>:
>> On Jun 28, 2009, at 11:12 PM, Robert O'Callahan wrote:
>> On Sat, Jun 27, 2009 at 11:44 AM, L. David Baron  
>> <dbaron@dbaron.org> wrote:
>>> I have another question about transitions that I think ought to be
>>> addressed in the spec ( http://dev.w3.org/csswg/css3-transitions/ ),
>>> though in this case I'm not exactly sure how it should be addressed
>>> in the spec.
>>> This is the question of whether transition should be associated with
>>> a change in style on a content node, or a change in style on a
>>> rendering object (a box).  Either solution poses a bunch of
>>> problems.
>>> If transitions are associated with the style on an element (DOM
>>> node), then we have problems in any case where a content node has
>>> more than one style.  The main case of this I can think of is
>>> pseudo-elements.  For example, I think it's hard to do something
>>> sensible with:
>>>  p { color: gray; }
>>>  p::first-line { color: black; }
>>>  p:hover { color: blue; }
>>>  p:hover::first-line { color: aqua; }
>>>  a { transition: 3s color; }
>>> then it's really not clear what the transition on the anchor should
>>> be when the p goes into the :hover state (either when the anchor is
>>> split between the first line and the second, or when the anchor is
>>> entirely in the first line).
>> How about: if an element has a first-line or first-letter rule  
>> setting a
>> property on it, then transitions on that property are disabled for  
>> the
>> element and all its descendants.
>> I'm not understanding why transitions can't be made to work on  
>> first-line
>> and first-letter?
>> dave
>> (hyatt@apple.com)
> Because in that case you would have two starting values and two ending
> values, one for the part of element that inherits from ::first-line,
> the other from the part of element that inherits from the element
> directly, whereas transitions expect one.

Sure, but I don't see why that is a problem, as long as you specify  
what happens.

Received on Monday, 29 June 2009 15:14:05 UTC

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