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<switch>

From: Erik Dahlstrom <ed@opera.com>
Date: Thu, 23 Jun 2011 14:01:05 +0200
To: "www-svg@w3.org" <www-svg@w3.org>
Message-ID: <op.vxi2b3zrgeuyw5@localhost.localdomain>
Hello,

I'm wondering what good is the <switch> element if it doesn't seem to read  
the requiredFeatures attribute from unknown elements.

Additionally it doesn't fully disable processing of the non-chosen  
subtrees, as illustrated by the audio/video example below.

Questions:
* What should happen in the switch below?
* Should the audio from the video be heard?
* Should the requiredFeatures attributes be used by the switch even though  
these elements
   are unknown? Or is requiredFeatures only possible on svg elements that  
the UA knows about?
* Given the current state of implementations <switch> is very close to  
useless, how do we want to proceed wrt this for SVG2?

Example:

<svg xmlns='http://www.w3.org/2000/svg'  
xmlns:xlink='http://www.w3.org/1999/xlink' viewBox="0 0 400 400"  
id="svgroot">
	<text x="200" y="40" text-anchor="middle" font-size="9">You should see a  
video in the rectangle below if your browser supports
	<tspan x="200" dy="1.5em">foreignObject, HTML5 video and Ogg Theora  
(maybe).</tspan></text>
	<rect x="100" y="100" width="200" height="200" stroke-width="4"  
stroke="black" fill="none"/>
	<switch>
		<myCustomFooElement xmlns="http://example.com/foobarML" width="400"  
height="400" fill="red" requiredFeatures="bar"/>
		<aNewSvg5Element width="400" height="400" fill="red"  
requiredFeatures="SVG5featurestring"/>
		<foreignObject id="fo" x="100" y="100" width="200" height="200">
			<div xmlns="http://www.w3.org/1999/xhtml">
				<video width="200" height="200" autoplay="autoplay"  
controls="controls">
					<source src="example.ogv" type='video/ogg; codecs="theora, vorbis"'/>
				</video>
			</div>
		</foreignObject>
	</switch>
</svg>


-- 
Erik Dahlstrom, Core Technology Developer, Opera Software
Co-Chair, W3C SVG Working Group
Personal blog: http://my.opera.com/macdev_ed
Received on Thursday, 23 June 2011 12:01:36 GMT

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