MRG: Add support for hemi=split in time_viewer

[GuillaumeFavelier]

This PR starts the work on hemi=split. Let's go incrementally on this one. For now I put all the controls on the first view.

Using plot_visualize_stc.py with hemi=split:

The zoom between the views is not linked, that would be nice to have I think.

ToDo

• Unify show_view() when hemi=split or when len(views)>1
• Fix playback when len(views)>1
• Fix default orientation value

It's an item of #7162

[GuillaumeFavelier]

Sadly with hemi=split and views=['lat', 'med'], the sliders got lost in the process:

Just checking with time_viewer=False:

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[agramfort]

any idea what's going on?

…

[GuillaumeFavelier]

I'm not sure but it could be related to pyvista/pyvista#513

[GuillaumeFavelier]

Or anyway I think we should wait for this issue to be solved in order to have full control on the sliders position between the views.

[larsoner]

Agreed

[GuillaumeFavelier]

Locally, following pyvista/pyvista#513 (comment) method, I managed to retrieve them:

I can try to patch in _TimeViewer while waiting on a decision upstream.

Note: the views are not correct still but this is a different bug*

[GuillaumeFavelier]

How show_view() should work in a hemi=split scenario? For now all the views are linked I guess it's not the most useful.

Should we duplicate the orientation slider in each view?

[larsoner]

How show_view() should work in a hemi=split scenario?

My advice is to always look first at PySurfer to see what it does to at least get an idea:

https://pysurfer.github.io/generated/surfer.Brain.html#surfer.Brain.show_view

In this case it has row/col indices, which seems like a sensible API

Should we duplicate the orientation slider in each view?

That would be great!

[GuillaumeFavelier]

I think it's better now but the default values for the orientation slider are still not correct. Note that the interaction with the user remains correct:

[GuillaumeFavelier]

This was a big refactor but now playback works too:

[larsoner]

Beautiful!

[GuillaumeFavelier]

With this, the issue with the default values of the orientation sliders should be fixed.

[larsoner]

Should we test/review/merge or wait for PyVista fixes upstream?

[GuillaumeFavelier]

Feel free to review/test/merge this one @larsoner , @agramfort

[GuillaumeFavelier]

Oh and actually in your original comment @larsoner, you wanted to move some UI elements. If you test and you're not satisfied by the current setup, you can also let me know

[agramfort]

works for me ! nice work @GuillaumeFavelier

[larsoner]

Works beautifully, awesome @GuillaumeFavelier !