[FEAT] "x unified" hover mode working across subplots

[emmanuelle]

This would make it possible to display the information of several subplots in the same hoverbox. Probably this would need an attribute since this behaviour is not desired in all cases.

[alexbhatt]

it would be most helpful, particularly in visualizing across COVID time series for multiple graphs; linked across R and python functionality.

[GitJJ]

I would also find this feature particularly useful.

[schoolie]

+1, would love to see this feature.

[g-deoliveira]

+1, this would be great

[nicolaskruchten]

Thanks for the enthusiasm, folks! It's a good feature and we'd love to have it in the library but it's not on anyone's roadmap at the moment. That said, we as maintainers would be happy to help someone from the community to implement it, or to accept sponsorship to get it on to our short-term roadmap :)

A few notes re how this might work at the schema/behaviour level... This would need to be one or likely a few new accepted values for hovermode: we currently accept closest, x and x unified. In both the latter cases, hovering over a trace linked to a given pair of x and y axes causes hover labels to appear for each trace linked the same x/y axis pair. We would need a variant on both x and x unified, perhaps something like all x and all x unified, which would cause hover labels to appear for every trace linked to the same x axis, regardless of y axis. We would also need to think about "matched" axes, and this could be yet another flavour of hovermode (all x and matched x?). We'd also need to think about what this would visually look like in unified mode: would there be one unified label per x/y pair or one big unified label near the cursor? We'd also need to take into consideration spikelines, especially with matched axes.

[immartian]

it would be most helpful, particularly in visualizing across COVID time series for multiple graphs; linked across R and python functionality.

exactly, like this one https://covid19-projections.com/path-to-herd-immunity/

[POI-Root]

+1, this would be very helpful

[yhmickey]

+1

[InvisOn]

Using the Generic Crossfilter Recipe may be a suitable alternative for some people. I've used it with some success to highlight points across subplots.

[GreekQuant]

+1

[GlebMorgan]

+1
Probable duplicate: #2114

[nicolaskruchten]

Yes, this is a duplicate of #2114 and in the same state: it's very unlikely that anyone on the Plotly team can work on this without a financial sponsor, although we'd be happy to work with someone from the community who wants to implement this themselves and submit a pull request.

[Disorrder]

+1

[Sank-WoT]

+1

[jacobrichey]

+1

[rudolferemyan]

+1

[SIDD2310]

+1

[MarcSkovMadsen]

+1. Would love this feature too.

[loicduffar]

+1
Still not in the road map ?

[Sladerix]

+1

[Episkiliski]

+1.
This would really make a difference using Plotly from my point of view.

[AlanCPSC]

+1
Related bug here: add_hline() breaks when axis is shared

[walkerpayne]

+1 :)

[chikko80]

+1

[Cian-Byrne]

+1

[drypatrick]

+1

[sde-cdsp]

+1

[giudici-uturn]

+1

[raja-jain-skydio]

+1

[drypatrick]

I found how to make it works, check out the codepen

[archmoj]

This would be resolved by #6947.