Re: [css-transforms] transform interpolation rules should operate better on their own results


On Feb 27, 2014, at 6:54 PM, L. David Baron <dbaron@dbaron.org> wrote:

> On Thursday 2014-02-27 15:49 +0000, Dirk Schulze wrote:
>> You have the start and end value and know when you interrupted the animation. So you could reverse animation function and therefore the animation using the same algorithms as you started the animation.
> 
> You could, and that would address this case.  It would probably be a
> good idea to change the spec to say this.

Hm. Do you think the spec implicates that this can not be done? If so I will change the section in question.

> 
> Though it still wouldn't address any case of this problem where the
> intermediate value made a round-trip through Javascript code.
> 
>> Is it correct to assume that the interpolation values that you get by matrix interpolation can not be reversed correctly? If that is the case, do you have other suggestions?
> 
> I'm not quite sure what you mean, but I don't have other ideas other
> than doing numerical interpolation for perspective(), as you
> suggest:
> 
>> We could do a numerical interpolation for perspective() as well. I need to investigate why chose not to do this.

I didn’t check yet why we do not interpolate perspective() directly. My guess is that WebKit and specifically CA in the backend would not support this. CA is important for accelerated animations of transforms in WebKit.

Greetings,
Dirk

> 
> -David
> 
> -- 
> 𝄞   L. David Baron                         http://dbaron.org/   𝄂
> 𝄢   Mozilla                          https://www.mozilla.org/   𝄂
>             Before I built a wall I'd ask to know
>             What I was walling in or walling out,
>             And to whom I was like to give offense.
>               - Robert Frost, Mending Wall (1914)

Received on Thursday, 27 February 2014 19:53:06 UTC