- From: Thierry MICHEL <tmichel@w3.org>
- Date: Sat, 13 Aug 2005 00:30:22 +0200
- To: "Glenn A. Adams" <gadams@xfsi.com>
- CC: Erik Hodge <ehodge@real.com>, W3C Public TTWG <public-tt@w3.org>
Dear Erick, If you require any further follow-up please do so, and if you are satisfied with the TTWG response, please acknowledge it by replying to this mail and copying the TTWG public mailing list: public-tt@w3.org Regards, Thierry Michel Glenn A. Adams a écrit : >Dear Erik, > >Thank you for your comments, [1], on the DFXP Last Call Working Draft >[2]. The TT WG has concluded its review of your comments and has >agreed upon the following responses. > >If you require any further follow-up, then please do so no later than >September 1, and please forward your follow-up to <public-tt@w3.org>. > >Regards, >Glenn Adams >Chair, Timed Text Working Group > >************************************************************************ > >Citations: > >[1] http://lists.w3.org/Archives/Public/public-tt/2005Apr/0044.html >[2] http://www.w3.org/TR/2005/WD-ttaf1-dfxp-20050321/ > >************************************************************************ > >Comment - Issue #14 [1]; 26 Apr 2005 10:10:15 -0700 > >It has been said on other threads that introduction of the timing >model into the layout was due to the following: > > > >>>(1) we wanted regions to be temporally activated/deactivated; >>>(2) we want to animate certain region styles, such as background color >>>(which is independent of background colors deriving from content >>>elements) and position; >>> >>>In order to provide these temporally sensitive features, we need to >>> >>> >make > > >>>regions timed elements, which implies a timing context, which in turn >>>indicated a need for having the root container element <tt/> be a >>> >>> >timed > > >>>container. >>> >>> > >The use of timing inside layout elements (and, in turn, in >the root container element <tt/>) is not necessary if certain >other attributes are allowed. I feel that adding timing to >these elements is adding unneeded complexity; if left as is, >I fear a lot more investigation and documentation will need >to be done to cover the non-obvious edge cases. > >You can do both of the things you described, above, in >SMIL 2.0 without the existence of region timing attributes. > >(1) To temporally activate/deactivate regions: >You could add the "showBackground" region attribute to TT >and allow the value of "whenActive". See: > > http://www.w3.org/TR/SMIL2/layout.html#adef-showBackground > >When "whenActive" is active, "...the background color will >not be shown in the region when no media object is rendering >into that region". Also, you could allow animation of that >attribute by using a <set> or <animate> element in the body >that targets the region and its showBackground attribute. >The latter option would allow you to turn the region's display >on and off when no text was displayed in it. When text is >displayed in the region and you want it to be hidden, you can >move it behind other regions, resize it to 0x0, move it off >screen, ...etc. The second two are contrived, I admit, but >moving a region behind another is not, IMHO. > >(2) To animate region styles, you could use the <set> and/or ><animate> element in the body, with the region's id as the >targetElement value. For instance, the following SMIL2 >Language-profile presentation animates the region's color >from blue to red to yellow then back to red then back to >blue at one-second intervals: > > ><smil xmlns="http://www.w3.org/2001/SMIL20/Language"> > <head> > <layout> > <root-layout width="340px" height="280px" /> > > <region id="r1" regionName="foo" > top="10px" left="10px" > height="240px" width="320px" > > backgroundColor="blue" /> > </layout> > </head> > <body> > <par> > > <img src="data:text/plain,Hello" width="50px" height="50px" > region="r1" dur="5s" /> > > <set targetElement="r1" attributeName="backgroundColor" > to="red" begin="1s" dur="3s" /> > > <set targetElement="r1" attributeName="backgroundColor" > to="yellow" begin="2s" dur="1s" /> > > </par> > </body> ></smil> > >Note: In SMIL 2.0 you can smoothly animate from one value to >another if the value is numerical, e.g., from="#0000FF" (blue) >to="#FF0000" (red). SMIL 2.0 also has a shortcut for smoothly >animating color called (naturally) "animateColor". > >Response: > >The TT WG believes the intended usage is implementable, but may need >additional clarifying language in section 10.4 that establishes the >time interval context for /tt/head/layout/region elements based on a >time intervals resolvable on /tt, /tt/head, and /tt/head/layout, >respectively, all three of which are identical. > >If during the Call for Implementation (CR) phase of DFXP it is found >that the present syntax and/or semantics is unimplementable or in need >of further clarification, then the TT WG has an option to exclude this >feature from a subsequent Proposed REC (PR). > >************************************************************************ > > > > >
Received on Friday, 12 August 2005 22:30:50 UTC