[csswg-drafts] `scroll-snap-align` assignment + `scroll-behavior: smooth` interpolation (#7372)

argyleink has just created a new issue for https://github.com/w3c/csswg-drafts:

== `scroll-snap-align` assignment + `scroll-behavior: smooth` interpolation ==
`[css-scroll-snap]`

### Interop Issue
Firefox doesn't currently align with Chromium and Webkit. There's differences in the results of orchestrating `scroll-behavior: smooth` and scroll snap alignment. I found it because I was expecting smooth scroll transitions when I control the scroll position via user interactively assigned snap points. 

<details>

<summary>Watch a comparison of Firefox and Chrome</summary>

https://user-images.githubusercontent.com/1134620/173856866-2bd1ac7d-4909-4a59-8424-c2ceab6bb01f.mp4

</details>

try the reduced case 👉🏻 https://snap-gallery.netlify.app/horizontal/tap-to-snap/

<br>

### Desired Functionality
In my opinion Firefox is doing it correctly. Author has requested `scroll-behavior: smooth` and the scroll position is updating, interpolate to the new destination. 

**Use Cases:**
- removing a snap child via updated style
- adding a snap child via updated style
- append a new child that also becomes the new (maybe only) snap child
- your use case here?

<br>

### Actions / To Do?
- [ ] gather feedback / resolutions about expected behavior
- [ ] add spec note to `scroll-snap-2` with `scroll-behavior` interaction specifics
- [ ] add 3-4 WPT tests to improve interop

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/7372 using your GitHub account


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Received on Wednesday, 15 June 2022 14:54:07 UTC