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Re: Offset or buffers

From: Chris Lilley <chris@w3.org>
Date: Tue, 23 Jan 2007 19:56:35 +0100
Message-ID: <1109900986.20070123195635@w3.org>
To: "andy@centremaps.co.uk" <andy@centremaps.com>
Cc: www-svg@w3.org, andy@centremaps.co.uk

On Thursday, December 14, 2006, 12:29:00 PM, andy wrote:

accu>     
accu>   
accu>   

accu> We’re doing various bits with SVG but really just using the
accu> existing tools. I wondered whether anyone has already worked on
accu> a function which would create a shape offset by a set distance
accu> from an initial polygon. The particular example I have in mind
accu> is the intention of creating a ‘buffer’ around a line – in the
accu> real world this might be to illustrate all items with in 1
accu> kilometre of the outline of an industrial estate.

Not that this will help you in terms of current implementations, but
this sort of functionality is covered by the planned Vector Effects
for SVG 1.2.

http://www.w3.org/TR/2004/WD-SVG12-20041027/vectoreffects.html

In your example, you would set a thick stroke (corresponding to your
1km zone outside the shape, at your map scale) then veStrokePath to
convert the stroke to a path, then veUnion with the original shape to
get the expanded shape.

This sort of functionality is available in some authoring tools, such
as inkscape. Vector effects would allow such constructive geometry
operations to happen in the client, dynamically.

-- 
 Chris Lilley                    mailto:chris@w3.org
 Interaction Domain Leader
 Co-Chair, W3C SVG Working Group
 W3C Graphics Activity Lead
 Co-Chair, W3C Hypertext CG
Received on Tuesday, 23 January 2007 18:56:39 GMT

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