Re: [svgwg] Provide ability to control animation direction of SVG animation elements (#881)

SMIL 2.1/3.0 have some attributes like accelerate, decelerate, speed, autoreverse to simplify some simple effects.
Initially there was the idea to add something from this to the SMIL used in SVG in the current draft for SVG2.0.
But meanwhile anyway, allmost every new features are removed again from the draft, that could have been interesting for authors and that already had an agreement in the past working group to be required for SVG.

There seems to be low or no activity both in completing implementations of SVG 1.1, SVG 1.2 tiny or the specify the SVG 2 draft in some meanigfull way for authors with the agreed and required features.
Therefore in practice my impression is, that authors have to work with those feature, which already work for further years. 

I used declarative animation a lot to visualise motion of objects., for example planets arround a star.
Typically it is sufficient to calcualte simply a long values list with lots of values to get the intended effect.
In case of exactly two objects (two stars for example or planet and moon) there is an exact solution available including keyTimes. But else one has to calculate anyway numerically.
A nice example for using keySplines is to visualise the exact solution for a falling object near the surface of the earth without friction. Well, depending of the kind of fiction one has to find the values again numerically.

keyTimes, keySplines are nice features, but  indeed, for an arbitrary accelerated motion this means some more calculations to get some more accurate effect in theory with less values but then with this long list of keyTimes, keySplines, therefore finally it save almost nothing in file-size.

With animateMotion using a path and keyPoints you already have an option to move forward and backward in an almost arbitrary way. 
But animate, animateColor and animateTransform have no attribue keyPoints to get a similar effect with a short  values list.
Therefore for them one has to repeat the values directly, what requires finally similar file size and calculation efforts.
Therefore not really a requirement for simplification for authors.

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Received on Sunday, 8 May 2022 14:48:15 UTC