Shared axes?

[jbrea]

trafficstars

Is it possible to generate subplots with shared axes like https://plot.ly/javascript/subplots/#subplots-with-shared-axes?

[sglyon]

Hi @jbrea it is definitely possible, though there isn't a "built in" way to do it yet.

The example you linked to would look like this in PlotlyJS.jl:

data =  [
    scatter(x=1:3, y=2:4),
    scatter(x=20:10:40, y=fill(5, 3), xaxis="x2", yaxis="y"),
    scatter(x=2:4, y=600:100:800, xaxis="x", yaxis="y3"),
    scatter(x=4000:1000:6000, y=7000:1000:9000, xaxis="x4", yaxis="y4")
]
layout = Layout(
    xaxis_domain=[0, 0.45],
    yaxis_domain=[0, 0.45],
    xaxis4=attr(domain=[0.55, 1.0], anchor="y4"),
    xaxis2_domain=[0.55, 1],
    yaxis3_domain=[0.55, 1],
    yaxis4=attr(domain=[0.55, 1], anchor="x4")    
)
plot(data, layout)

I think this would be a good addition to the library, the only question is what the API should look like.

One thing that could work would be to have a function

function share_axes!(l::Layout; rows::Vector{Int}=Int[], cols::Vector{Int}=Int[])
    # make sure `rows` and `cols` aren't both empty

    # for each row in rows, make all the subplots in that row share axes with left most subplot in that row

    # for each column in cols, make all subplots in that col share axes with bottom most subplot in that col

end

function share_axes!(p::Plot; rows::Vector{Int}=Int[], cols::Vector{Int}=Int[])
    share_axes!(p.layout, rows=rows, cols=cols)
end

function share_axes!(p::SyncPlot; rows::Vector{Int}=Int[], cols::Vector{Int}=Int[])
    share_axes!(p.plot, rows=rows, cols=cols)
end

Does that seem reasonable to you?

[jbrea]

Hi @sglyon

Thanks much for the quick response and the example!

I like your proposition for the extension of the API. However, I am not sure how to handle cases with multiple custom sized subplots, if you plan to also create an API for them. E.g. in https://plot.ly/javascript/subplots/#multiple-custom-sized-subplots it is not clear, if the bottom figure is in column 1 or 2.

As an alternative, what do you think about functions like

function share_xaxis!(plots::Vector{Plot})
# for each plot in plots share x-axis with plots[1]
end

[sglyon]

That's also a good idea. The one tricky thing is that a figure with multiple subplots will be just one Plot object... I need to think on that a bit more

[cstjean]

Ref. https://github.com/JuliaPlots/Plots.jl/issues/1371

[kylecarbon]

@sglyon any chance of an update? :) The example above is very helpful but my use-case is slightly different (I think?).

I am in a situation similar to subplots3(), in that I am generating many other plots, each with multiple traces. I'd like to be able to generate those plots, then combine any subset of them, then link all their x-axes. For example, in the subplots3() example, I sometimes might want only to plot 2 or 3 of the subplots, rather than all 4. But in all situations, I would like to be able to link the x-axis across all plots. Maybe this is already possible but I'm just having trouble with the syntax?

Either way, enjoying PlotlyJS so far! :)

[sglyon]

Hey @kylecarbon I haven't put more thought into this since the discussion fizzled out early this year.

Would the proposed API I had in the comment above with the share_axis! functions help in your case?

It is totally possible to do right now, but you would have to build the Layout object that does it by hand

[kylecarbon]

I think the share_axis! function would work just fine, as long as it handles all nested subplots (like you already mentioned above). That way, I can share the x-axis for all subplots, as well as plots in other windows.

I tried building the Layout object by hand but had trouble with it :/