Wrap tutorial doesn't work anymore

[Moelf]

in #3736 and #3816 we added https://docs.makie.org/v0.21/tutorials/wrap-existing-recipe

but it actually doesn't work anymore:

julia> using MakieCore, CairoMakie

julia> struct MyHist
           bincounts
           bincenters
       end

julia> function Makie.plot!(plot::Hist{<:Tuple{<:MyHist}})
           barplot!(plot, plot[1])
           plot
       end

julia> hist(h; color=:red, direction=:x)
ERROR: ArgumentError:     Conversion failed for Plot{Makie.barplot} (With conversion trait PointBased()) with args: Tuple{MyHist} .
    Plot{Makie.barplot} requires to convert to argument types Tuple{AbstractVector{<:Union{Point2, Point3}}}, which convert_arguments didn't succeed in.
    To fix this overload convert_arguments(P, args...) for Plot{Makie.barplot} or PointBased() and return an object of type Tuple{AbstractVector{<:Union{Point2, Point3}}}.`

@SimonDanisch @asinghvi17

[asinghvi17]

I don't think the specific example you showed should ever work - the error message is correct in this case, barplot doesn't have an overload defined for MyHist.

You would want either barplot!(plot, @lift($(plot[1]).bincenters), @lift($(plot[1]).bincounts)) which does work (though it doesn't pass attributes down), or to define a specific convert_arguments for barplot.

Plus, the examples are all rendered in the documentation ;) which means they do work there at least!

[Moelf]

Good point 🤔. Works in the docs because we have the convert arguments.

In this case I want to add extra keyword arguments to errorbar(MyHist), they change how the errorbars are calculated. I think in this case I have to defer these into the convert arguments, but how? Can I just add extra arguments to convert_arguments?

[asinghvi17]

used_attributes(::Type{PlotType}, args...) = (:mykw1, :mykw2) should do it, you can then access those kwargs in convert_arguments! You will have to specify the argument types though.

[asinghvi17]

See e.g. SciMLBase's Makie ext for an example.

[Moelf]

You mean I have to specify plot type?

Btw just as an FYI, this approach did work before 0.21, maybe by mistake?

[asinghvi17]

Both plot type and argument types for dispatch purposes. So for example

Makie.used_attributes(::Type{<: Errorbars}, h::Hist1D) = (:error_function,)
Makie.convert_attributes(::Type{<: Errorbars}, h::Hist1D; error_function = nothing) = do_something(h, error_function)

As for this working before 0.21: did the plot turn out correct?! That would definitely be a mistake IMO :D

[Moelf]

plot looks correct: Moelf/FHist.jl#118

[Moelf]

Makie.convert_attributes(::Type{<: Errorbars}, h::Hist1D; error_function = nothing) = do_something(h, error_function)

you meant convert_arguments?

[asinghvi17]

ah yes, my bad

[Moelf]

worked like a charm: Moelf/FHist.jl#118 (comment)