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RE: A proposal for declaritive drawing (<replicate>) to be added into SVG

From: Dr. Olaf Hoffmann <Dr.O.Hoffmann@gmx.de>
Date: Wed, 7 Apr 2010 14:46:35 +0100
To: www-svg@w3.org, david.dailey@sru.edu
Message-Id: <201004071546.35752.Dr.O.Hoffmann@gmx.de>
Dailey, David P.:
>Again one of the compelling things to me about the concept is that much of 
>the programming work will already have been written by the implementers in 
>their SMIL implementations: for example this morning I was contemplating 
>writing a path interpolation routine myself in JavaScript that would 
>interpolate between any two paths and yet quickly realized that this would 
>be a non-trivial exercise, given all the subcommands of SVG <path> elements. 
>Those who have implemented SMIL have already done all that of course, and 
>hence could reuse those functions for <replicate>.

Animation interpolation between two arbitrary paths is not available either.
What can be animatated/interpolated is pretty much restricted for paths.
Every value of the values lists has to have the same number of path
commands in the same order. This means, the animation requires only
an interpolation between lists of numbers as for other attributes with lists
as values.
In SVG tiny 1.2 you have additionally the option for a discrete animation
with arbitrary paths as values and you can switch from absolute commands
to relative. For your application a correspondence to discrete animation
might not be very helpful. In such a case one can use single path elements
instead of replicates causing similar source code size.

Interpolation between two arbitrary paths is plurivalent in general and
undefined. To do this, one could for example define parametrisations
for the complete paths and interpolate between the parametrisations.
But who knows, for which cases and applications the result might be
useful? ;o) And something like a 'state' of 61% elliptical arc and 39%
cubic curve might require a new rendering algorithm ;o)

Olaf
Received on Wednesday, 7 April 2010 13:49:01 GMT

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