- From: Jim Ley <jim@jibbering.com>
- Date: Fri, 9 May 2003 08:34:29 -0000
- To: www-svg@w3.org
I think in general the Alternate content section could be simply extended to cope with low bandwidth aswell as different display resolutions - it may also be possible to extend it in such a way that you can specify different images for different sub-regions for when zooming in/out without forcing the download of a complete more accurate map and the bandwidth costs of that. (basically doing what we do in Level-of-Detail script changing situations) Exactly how that extension might be managed I'm not sure... For the bandwidth case, a simple advisory content-size attribute on the subImage element would provide a hint to the UA, which it could then use in the decision making process. For the more complicated LOD regional part, then the subImage elements could also have x/y/w/h attributes defining the region of the parent Image element that they refer to, looking something like this: <image x="200" y="200" width="100px" height="100px" min-pixel-size="1" max-pixel-size="1" xlink:href="myimage.png"> <subImage xlink:href="myimage-lg.png" min-pixel-size=".5" max-pixel-size=".5" x="25px" y="25px" height="50px" width="50px"> <desc>An alternative image for the central portion of the parent Image</desc> </subImage> </image> The UA can then choose to switch to the subIamge if the zoomed region would be better served by it. This would give us Level-of-detail functionality without needing scripting. What would happen in situations where the zoom overlaps regions which don't have a subImage is something else I don't know about, rendering both images would be possible, or you could just use the parent one. Jim.
Received on Friday, 9 May 2003 08:40:50 UTC