Revisions panel and slider UI design considerations

[ntsekouras]

In this PR the new revisions panel was added to a few more post types, as it's part of the Editor Inspector: Use DataForm experiment right now.

There were a few suggestions there about the design of revisions handling altogether that are worth discussing in a separate issue. These suggestions doesn't include just the new panel, but also the way of navigating between revisions - that means the revisions slider.

I'd appreciate if @t-hamano and/or @Mamaduka could chime in (or even update the issue itself) to reflect properly their feedback.

For reference I'm linking a couple of those comments: 1, 2.

I don't think this timeline is very useful when editing a template or post, and it will take up space in the sidebar. Maybe we should replace the topbar slider with this panel when the user is viewing revisions.

Perhaps we should consider this first? Certainly, just because the classic revision uses a slider doesn't mean we have to follow suit. So, will the UI be something like a global style, like this?

--cc @WordPress/gutenberg-design @jameskoster @jasmussen

[ellatrix]

Resharing my comment since that PR is about to be merged.

Perhaps we should consider this first? Certainly, just because the classic revision uses a slider doesn't mean we have to follow suit. So, will the UI be something like a global style, like this?

The thing I agree with here: we should add a timeline view to the document inspector in the revisions screen. That was the plan, but got distracted with general 7.0 stuff. I'm also not sure how much it makes sense to add a timeline "preview" as a panel in the editor, it feels like it would only be harder to get to the revisions screen.

The thing I disagree with: to remove the slider. Having two distinct ways to navigate the revisions is fine. One navigates revisions on a coarse level and allows you to browse them really quickly. It will also allow us to add a sort of "flame graph" in the next release. (Didn't have time for that either this cycle.) The timeline proves a finer way to navigate revisions with different details. It's a bit like a sewing machine having a pedal to sew fast and a wheel to slowly get through a tricky part. Having different ways to browse something is not a bad thing in my opinion, I don't think we have to choose.

[Mamaduka]

I've changed my mind regarding the slider 😄 @ellatrix has a good point, and I'm looking forward to the redesigned slider.

I still don't think we should display the revision "timeline" in the editor; we should only display these controls when in-editor revisions mode is enabled.

[t-hamano]

I still don't think we should display the revision "timeline" in the editor

I don't have a strong opinion on keeping the slider, but I agree with you on the above points.

[ntsekouras]

Copying @jameskoster's comment here:

Agree with all the feedback. In the context of this PR I suppose it raises a question about whether we need to show the timeline in both locations. Access to revisions could theoretically be much simpler if we're going to display the timeline in the Revisions UI, for instance maybe the "Last edited 2 days ago" text links through and we don't need a dedicated panel? Fine to explore separately I guess.

[jameskoster]

Just adding my +1 to the suggestions:

• Remove timeline from the document Inspector
  • Simplify access to revisions (no dedicated panel)
• Add timeline to Revisions Inspector.
• Keep revision slider, though it may need an a11y review. We may also need to figure out how it behaves when there are hundreds of revisions.

At a higher level, it would be nice to bring greater parity to the revision experience in Global Styles and Posts/Pages/Templates. I don't have strong feelings about which approach is better, but I think ideally they'd be broadly the same.

[t-hamano]

We may also need to figure out how it behaves when there are hundreds of revisions.

I have tried testing hundreds of revisions, and it seems that the classic revisions display all of them as a scale:

On the other hand, in the new revision UI, the slider becomes visually hidden.