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Re: SMIL section of state-of-the-art document done

From: Jack Jansen <Jack.Jansen@cwi.nl>
Date: Mon, 27 Oct 2008 13:31:29 +0100
Cc: "Media Fragment" <public-media-fragment@w3.org>
Message-Id: <FB4F423C-8A69-4E8A-BD1B-F655F0D6D251@cwi.nl>
To: Silvia Pfeiffer <silviapfeiffer1@gmail.com>


On 27 okt 2008, at 12:11, Silvia Pfeiffer wrote:

> Wow, that's totally awesome. I am inspired to write the CMML/Annodex  
> section. :)

You know, that would be totally awesome too:-)

> BTW: I like the quadruple way of specifying a spatial fragment (area)
> in SMIL: x-offset, y-offset, width, height. We should consider using
> that for spatial media fragment URIs.

There's a problem with 4-tuples for rectangles (that I've already  
touched upon in the piece of text) and that is that sometimes it's  
intended to be x,y,w,h and sometimes it's l,t,r,b (or x1,y1,x2,y2  
which is usually the same).

In SYMM this bothered us to no end, because we wanted to be compatible  
with the spec from which we lifted the feature, but this meant we  
couldn't be internally consistent anymore:-( The SMIL native method is  
to spell things out: region boundaries can be specified with  
attributes top,left,right,bottom,widht,height, with all values  
defaulting to "auto". So as long as you don't overspecify any  
dimension you're fine.

In hindsight, I think it might have been better not to use any four- 
tuples but in stead spell things out (so, in stead of panZoom="25%,25%, 
50%,50%" use clipLeft="25%" clipTop="25%" clipWidth="50%"  
clipHeight="50%").

Also note that <area> *must* use ltrb-style to be consistent: if the  
shape is a polygon you must specify x0,y0,x1,y1,x2,y2, ... anyway, so  
if you don't do a point pair for a rectangle (but in stead a point,  
size pair) things become messy.


--
Jack Jansen, <Jack.Jansen@cwi.nl>, http://www.cwi.nl/~jack
If I can't dance I don't want to be part of your revolution -- Emma  
Goldman
Received on Monday, 27 October 2008 12:32:11 GMT

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