Animation: Implement 'Hooks.transition' hook

[Et7f3]

fix #121
We call it like Hooks.state
https://github.com/revery-ui/revery/blob/Et7f3/useTransition/examples/Hello.re#L11-L12 and it return a setter
https://github.com/revery-ui/revery/blob/Et7f3/useTransition/examples/Hello.re#L85
I have added some

      Printf.printf("transitionedOpacity: %f\n", transitionedOpacity);
      flush(stdout);

because opacity is a no-op on my windows (didn't try on other os)
If we have more hooks maybe add a Hooks demo for them.

Also It miss the last update. 😢

[glennsl]

This looks awesome! Opacity doesn't seem to work on Linux either, but I think that might just be on the image. It should work for simpler primitives. At least it does in Oni2.

I noticed from the logging that it never reaches 0.0 and 1.0 though.

[glennsl]

This seems like unnecessary indirection. IMO, at least, it would be clearer to just set ~repeat=false directly.

[Et7f3]

I use it two time 🤷‍♂ but yeah I agree.

[Et7f3]

Also It miss the last update. 😢

Now I explicitly set the value when the animation end: b5485f0#diff-cd777f7799e2787af430fc84ce54bf45R22. Maybe there is a cleaner way. Ihave tried with reducer like animation hook and it don't helped.

[glennsl]

It seems like the animation API could and ought to be tightened up quite significantly to provide a cleaner API, but I think that's a bit out of scope for this PR. Otherwise, except for the animation' hook, I think this is looking very nice now.

[zbaylin]

This is awesome and solves a lot of the a-functionality the current API uses (partly my fault 😨). One thing I might add would be an immediate parameter to the setX function, i.e. setOpacity(~immediate=true, 1.0).

Also, I know it's just convention, but it might make more sense to use the name transitionXTo (i.e. transitionOpacityTo(1.0)) rather than setX, which sounds more immediate.

I really hope this can get merged soon, because it will help a lot with my efforts on revery-material.

Great work @Et7f3 !!

[bryphe]

Awesome work @Et7f3 ! (and thanks @glennsl and @zbaylin for reviewing it!)

Such a nice primitive to have now 🎉