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Re: Smooth curves passing through/near a set of points. [ISSUE-2282]

From: Doug Schepers <schepers@w3.org>
Date: Wed, 17 Jun 2009 00:44:00 -0400
Message-ID: <4A387490.8060503@w3.org>
To: Chris Lilley <chris@w3.org>
CC: Patrick Ion <ion@ams.org>, W3C SVG Public Working Group <public-svg-wg@w3.org>
Hi, folks-

Raph Levien's Spiro work might be relevant to this topic, particularly 
with SVG fonts.  Some of this is implemented in Inkscape, which might 
make it a natural inclusion.



Chris Lilley wrote (on 6/11/09 11:34 AM):
> Hello Patrick,
> I hope this mail finds you well. I'm mailing you with a copy  to the
> SVG public list, because we would like your help on a mathematical
> problem we are having.
> A couple of years ago, at TPAC, we were discussing a class of curves
> with the property of passing through a set of points (or near, for
> some definition of near), and differing from the curves that SVG
> already has (cubic and quadratic Beziers) or might have (non-uniform
> rational b-spline curves) in that no off-curve control points are
> used to define the curve, only the on-curve knots.
> I suppose these are piecewise curves with some fairing or smoothness
> property where the pieces join.
> Does this ring any bells? I can't even recall the name for that class
> of curves, sorry.
> We have a couple of use cases for such curves, now; one is for
> graphing/charting applications where it is desired to run a smooth
> (for some definition of smooth) curve through a set of 2D points
> rather than joining them by a polyline.
> The second is to run a curve through a set of 3D points (where the 3D
> space is a colour space) to produce colour gradients from a list of
> colours, without perceptual discontinuities. Current gradients
> effectively connect colours by polylines, so there is a perceptual
> discontinuity at each colour stop.
> tracker, this relates to ACTION-2584
Received on Wednesday, 17 June 2009 04:44:09 UTC

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