RE: Re: animating the angle of an arc in SVG

Hi Domenico.

 

Yes, I thought of that in my post of it at ello:  https://ello.co/ddailey/post/FVIyP3VIkRGAhK3iU4ItNg . Of course part of the reason for doing it with SMIL (other than just seeing if I could), was to show folks how cool Erik’s example was.

 

I think that maybe playing with keySplines and keyTimes might make the approximation to a circle a lot better. 

 

Of course if SVG had something like 

 

as in <replicate> (see example at http://cs.sru.edu/~ddailey/svg/pathRep2JS.svg  ) :

 

<replicatePath xlink:href="#curve2 <view-source:http://cs.sru.edu/%7Eddailey/svg/pathRep2JS.svg#curve2> " xattribute="rx" yattribute="ry"/>

<replicatePath xlink:href="#curve <view-source:http://cs.sru.edu/%7Eddailey/svg/pathRep2JS.svg#curve> " xattribute="cx" yattribute="cy"/>

 

 

then one could perhaps allow the values of one of the arc attributes to follow a user defined curve (in this case, it would be a circle drawn as an arc)! (replicatePath currently doesn’t burrow into particular fields of a multi-valued attribute like the d of an arc, so that would be tough.)

 

cheers

David

From: [email protected] [mailto:[email protected]] 
Sent: Tuesday, December 09, 2014 11:51 AM
To: [email protected]
Subject: [svg-developers] Re: animating the angle of an arc in SVG

 

  

David,

 

It's jerky because the interpolation points between two pairs of x,y coordinates represents a segment ax,ay bx,by. Given that you can't use expressions, you can't force it to follow the points on the circle. If those points were drawn, they would represent a dodecagon. The arcs are really deflating to midway and then inflating until they reach the next proper hard-coded pair. We can call that the seasick effect.

 

The only way I can think of to overcome that problem is to have 360 arcs instead of 12. On a 1 degree basis the effect may be unnoticeable. Maybe using 60 arcs would also do the job. But then again, it's so much easier with scripting.

 

Domenico

 

 

 

 





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Posted by: "David Dailey" <[email protected]>
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