RE: Minutes, 22 August 2013 SVG WG telcon

Hi Brian,

Thanks for asking.

The concept is discussed a bit in the formal proposal, I think, but let me explain it with some examples and discussion.

Note in http://srufaculty.sru.edu/david.dailey/svg/SVGOpen2010/double7.svg
How we replicate along a curve using the following syntax"

<replicatePath xlink:href="#curve"  xattribute="cx" yattribute="ry"/>

The replicated object (in this case, an ellipse) takes on its cx and ry values from the x and y values of #curve.

Just as anything that can be animated can be replicated, the reverse is also true: constructs which work in the realm of replicate can easily be migrated into animate.

Accordingly we could introduce syntax like
 <animatePath xlink:href="#curve"  xattribute="cx" yattribute="ry"/>
So that instead of simply animating cx and cy to travel along a path, any simple valued attributes (and maybe even R or G or B) could take their functional values from a user-specified path.

Another example makes it perhaps easier to see:

In http://cs.sru.edu/~ddailey/svg/pathRep2JS.svg 
Two curves have been drawn, both of which affect the qualities of the replicated (or animated) ellipses. The yellow curve affects the cx and cy values of the ellipse (as it moves through space (via replicate) or time (via animate). The green curve affects the rx and ry values of the ellipses.

The thought is really quite simple: extend the class of attributes of an animation that may be affected by animatePath. Currently it only works for x and y values. Keysplines were introduced, I think, to try to give authors slightly more control over the way animations phase-in effects. The curves that are drawable through keysplines are a bit unwieldy and it seems to take folks a long time to wrap their heads around their use.  Being able to say: here is a curve; dear SVG, please use it, just makes sense.

Cheers
David


-----Original Message-----
From: Brian Birtles [mailto:bbirtles@mozilla.com] 
Sent: Sunday, August 25, 2013 7:32 PM
To: www-svg@w3.org
Cc: David Dailey
Subject: Re: Minutes, 22 August 2013 SVG WG telcon

Hi David,

Thanks for your mail.

(2013/08/23 20:01), David Dailey wrote:
> While ya'll are thinking about animation, remember the request from four or five years ago to allow, in addition to keysplines, the ability to have attribute values taken from drawn path coordinates, as was done in the ever-popular replicate proposal. It would be a far more intuitive way of allowing non-linear interpolations than keysplines, and ultimately, a far more precise and controlled way of managing things. Essentially it is like animating along a path, but for attributes other than just x and y.

We have this on the list of SVG 2 requirements but we couldn't work out what it means.[1] Do you have some concrete examples of this?

Thanks,

Brian

[1] http://www.w3.org/Graphics/SVG/WG/wiki/SVG2_Requirements_Commitments
no. 59

Received on Tuesday, 27 August 2013 01:34:53 UTC