interactive bokeh legend with datashader

[timothydmorton]

Is there any plan to make the click-to-mute feature of bokeh legends available for datashader images, or at least for overlays of different datashader images?

[philippjfr]

That's definitely an interesting feature request, I'm not actually sure if images can be given a legend entry atm but I'll investigate. As an alternative I made a similar proposal elsewhere, suggesting to add a toggle button instead: #1114.

[jbednar]

Seems like we could have such a legend for categorical plots, turning each category on or off when mapping from the stack of aggregates into the final image. I'd find that really useful, but it would require some custom coding at the HoloViews level to make it hook up to the Bokeh machinery for enabling line plots, since it needs to work in a completely different way.

[timothydmorton]

Yeah, that's exactly the use case I had in mind.

[jbednar]

If you get a hankering to dive into how Bokeh does it for the plots where it controls what's visible, and can see how to make that mechanism visible for when another library controls what's visible, I'd love to see the results! But this is something that crosses all three projects (Bokeh, HoloViews, and Datashader), so it's a bit tricky as a first task to attempt. @philippjfr could definitely do it, but he's got a lot on his plate.

[SebastianRiedel]

I'm just exploring Bokeh, HoloViews and Datashader, but coming from Plotly where mute-on-click legends are basically the default, this feature seems really important to (at least) me.

Is there any news or prototypical 'hacks' to get this to work?

[jbednar]

If you're comparing Plotly with Bokeh or HoloViews+Bokeh, they should all be the same in that respect -- I believe they can all happily create mute-on-click legends by default.

Datashader works entirely differently from those JavaScript-based tools, so any solution involving Bokeh+Datashader or Plotly+Datashader would need to a separate mechanism from what Bokeh and Plotly natively do, emulating the mute-on-click functionality but with a very datashader-specific mechanism. So regardless of what interactive front end you use , it will take some work to make it work with Datashader. It's work we basically know how to do, but it's not on our immediate priority list, so I wouldn't expect it to appear imminently. Meanwhile, any data file small enough for Plotly should already work fine with mute-on-click legends with Bokeh or with HoloViews+Bokeh.

[Mossi8]

Hi, I wanted to ask if there has been any progress or recent suggestions to make interactive legends for holoviews and datashader. Since, I would find this feature incredibly useful for categorical variables as you were saying.

Thanks so much for your time.

[jbednar]

Alas, the status is the same as 28 days ago; this is still a clearly useful feature, but it is not high on the priority list. There's definitely no way we could get to it in November or December, unless it turns out to be a prerequisite for something we already need to do; there's a lot in the queue before it!

[jlstevens]

Following on from Jim's comment I am assigning this issue to the 2.0 milestone. Hope we could address it sooner but I'm not particularly optimistic.

[mugurm]

Curious if there is progress on this. I am looking for the same capability.
I could see some version of this working by using an Image per category internally and letting the plotting library manage the visibility of the various images functioning as layers.