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Re: Pan Wrap

From: Jasper van de Gronde <th.v.d.gronde@hccnet.nl>
Date: Mon, 16 Jul 2012 17:30:24 +0200
Message-ID: <50043390.2010307@hccnet.nl>
To: www-svg@w3.org
On 16-07-12 16:56, Doug Schepers wrote:
> Hi, folks-
>
> I was just reminded of a use case I thought of long ago, but never
> articulated: the ability to wrap an SVG image on either (or both) the x
> or y axis.

This is effectively an example of wanting to construct a pattern with 
one of the wallpaper symmetry groups. These are extremely well 
researched, so when considering extending SVG with this kind of concept 
it could be very helpful to take a closer look at these:

http://en.wikipedia.org/wiki/Wallpaper_group#The_seventeen_groups

In particular, what you're suggesting is effectively group p1 (with some 
constraints on the possible translations), and with a little effort you 
could easily imagine adding support for at least some of the more 
closely related groups, like p2, pm, pg, pmm, pmg and pgg. All of these 
groups have real-world examples, although perhaps more for creating 
patterns than tiling the viewbox (although in a sense the whole SVG 
image is then treated as a pattern).

To continue your map use case, instead of just allowing horizontal 
wrapping, it might make sense to also allow vertical wrapping (for 
certain projections this makes perfect sense, look for the Peirce 
quincuncial projection for example). Now a simple "wrapping" isn't 
enough, you need something more, like p2 (which contains 180 degree 
rotations), or pm (which contains reflections).
Received on Monday, 16 July 2012 15:30:58 GMT

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