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Re: ISSUE-58 (showBackground animateable): shouBackground should not be animateable [DFXP 1.0]

From: Glenn A. Adams <gadams@xfsi.com>
Date: Sun, 19 Apr 2009 20:39:17 +0800
To: Sean Hayes <Sean.Hayes@microsoft.com>, Public TTWG List <public-tt@w3.org>
Message-ID: <C6113C75.A421%gadams@xfsi.com>

i will go ahead and make all style properties animatable; tts:dynamicFlow
can be easily handled by defining that a change in its value causes a reset
of the fill and clear flow timers; regarding dynamic flow having state
across significant synchronic intermediate documents, i believe i have dealt
with that previously in Section B.2;

g.

On 4/19/09 5:26 PM, "Sean Hayes" <Sean.Hayes@microsoft.com> wrote:

> Interesting you should say that, I had exactly the same thought last night.
> One of the original design principles was that timed text display should be a
> function of time, i.e. without state. The reasoning behind having attributes
> non-animateable was that it might be too expensive in terms of re-flow etc,
> but if at each moment in time the entire tree is effectively made anew. Then
> this reasoning seems unsound.
> 
> So I support the motion.
> 
> The only one I have some doubts about is dynamicFlow, because it seems to
> operate somewhat outside the same timeline, and thus have state across time
> ticks. Which is also why I think dynamicFlow should be dropped, or
> substantially reworked in order to fit with the above model.
> 
> Sean Hayes
> Media Accessibility Strategist
> Accessibility Business Unit
> Microsoft
> 
> -----Original Message-----
> From: public-tt-request@w3.org [mailto:public-tt-request@w3.org] On Behalf Of
> Glenn A. Adams
> Sent: 19 April 2009 7:11 AM
> To: Public TTWG List
> Subject: Re: ISSUE-58 (showBackground animateable): shouBackground should not
> be animateable [DFXP 1.0]
> 
> i propose we take a different approach: make all styles animatable
> 
> i note that at present, the following are defined as being non-animatable:
> 
> tts:direction
> tts:displayAlign
> tts:dynamicFlow
> tts:extent
> tts:origin
> tts:overflow
> tts:unicodeBidi
> tts:writingMode
> 
> in contrast, all of the (remaining) following properties are defined as
> animatable:
> 
> tts:backgroundColor
> tts:color
> tts:display
> tts:fontFamily
> tts:fontSize
> tts:fontStyle
> tts:fontWeight
> tts:lineHeight
> tts:opacity
> tts:padding
> tts:showBackground
> tts:textAlign
> tts:textDecoration
> tts:textOutline
> tts:visibility
> tts:wrapOption
> tts:zIndex
> 
> there doesn't seem to be any principled reason for making any of the above
> properties non-animatable; in fact, we have recently assumed that tts:origin
> (and perhaps tts:extent) is animatable in order to move a region to a new
> location; also, the following seem to be inconsistent on the surface:
> 
> * tts:textAlign is animatable, but tts:displayAlign is not
> * tts:wrapOption is animatable, but tts:overflow is not
> 
> if one supports animation for one property, then it should be fairly trivial
> to support animation on any other property;
> 
> therefore, i propose we make all the style properties animatable, which will
> make usage and authoring less subject to special case exceptions;
> 
> glenn
> 
> On 4/18/09 3:03 AM, "Timed Text Working Group Issue Tracker"
> <sysbot+tracker@w3.org> wrote:
> 
>> 
>> ISSUE-58 (showBackground animateable): shouBackground should not be
>> animateable [DFXP 1.0]
>> 
>> http://www.w3.org/AudioVideo/TT/tracker/issues/58
>> 
>> Raised by: Sean Hayes
>> On product: DFXP 1.0
>> 
>> tts:showBackground is listed in the specification as animateable. I cant see
>> why this is necessary. Unless we have a use case for this I propose it be set
>> to animateable: none
>> 
>> 
>> 
> 
> 
> 
Received on Sunday, 19 April 2009 12:40:00 GMT

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