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

From: Geoff Freed <geoff_freed@wgbh.org>
Date: Mon, 20 Apr 2009 13:31:48 -0400
To: "Glenn A. Adams" <gadams@xfsi.com>, Public TTWG List <public-tt@w3.org>
Message-id: <E36081A12A13F146AC32D7724B0E89120767F1AFC0@EXCHCCR.wgbh.org>

i have no problem with this proposal, but i do have a question.  by allowing animation on properties like tts:extent and tts:origin, would that allow the author to actually move a single caption-display region from, say, the lower third to the upper third, thereby avoiding the pre-definition of fixed regions as we've discussed before?

thanks.
g.


________________________________________
From: public-tt-request@w3.org [public-tt-request@w3.org] On Behalf Of Glenn A. Adams [gadams@xfsi.com]
Sent: Sunday, April 19, 2009 2:10 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 Monday, 20 April 2009 17:36:48 GMT

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