Conceptual problem with user recipes: draw a sphere before drawing the data

General Usage
,
1

I am trying to do a user recipe from RecipesBase.jl but I seem to not get the idea how Recipes work I fear.

Context.
I would like to do something that I thought was quite easy. Given the M=Sphere(2) from Manifolds.jl and a set of points (maybe just pts=[ [ 1.0, 0.0, 0.0], [0.0, 1.0, 0.0] ] I would like to be able to write

scene = plot(M,pts)
to draw a sphere and two markers where these points are,
Best would be that for the scene I could also add things using plot!(scene, M, pts2) for a second set of points.

Here’s my current approach – and I can’t find what I am doing wrong, I fear I have a conceptual problem with recipes still.

Here’s my current (nonworking) MWE

using Manifolds, Plots, RecipesBase

@recipe function f(
    M::Sphere{2},
    pts::AbstractVector{T};
    wireframe_lat=33,
    wireframe_lon=33,
) where {T}
    show_axis --> false
    φ_range = range(0,stop=2*π,length=wireframe_lon)
    λ_range = range(0,stop=π,length=wireframe_lat)
    x = [cos(φ) * sin(λ) for φ ∈ φ_range, λ ∈ λ_range] 
    y = [sin(φ) * sin(λ) for φ ∈ φ_range, λ ∈ λ_range] 
    z = [cos(λ) for φ ∈ φ_range, λ ∈ λ_range] 
    scene = plot() # I assume this should be the global plot? Wherefrom?
    wireframe!(scene, x, y, z)
    seriestype --> :scatter
    return [p[1] for p ∈ pts], [p[2] for p ∈ pts], [p[3] for p ∈ pts]
end

M = Sphere(2)
pts = [ [1.0, 0.0, 0.0], [0.0, 1.0, 0.0] ]
plot(M, pts)

and I also was not able to find something similar on the net.

How do I add something to a plot, when usually the recipe only returns x, y, z and I can’t seem to access the plot to add the sphere? It just plots the two points.

2

After a very quick glance at your code, I think you have a problem in the line with the following:

y = [sin(lon) * sin(lat) for φ ∈ φ_range, λ ∈ λ_range]

lon and lat are not defined.

1 Like
3

Thanks for noticing, sorry, I copied an old version – name them φ and λ and it works, the plot actually has both points in, just no sphere

I also edited the original post.

4

I found one trick that seems to be a step forward – @series from

but I can’t do a surface with that as I would do with surface(x,y,z) below

using Manifolds, Plots, RecipesBase

@recipe function f(
    M::Sphere{2},
    pts::AbstractVector{T};
    wireframe_lat=33,
    wireframe_lon=33,
) where {T}
    show_axis --> false
    φ_range = range(0,stop=2*π,length=wireframe_lon)
    λ_range = range(0,stop=π,length=wireframe_lat)
    x = [cos(φ) * sin(λ) for φ ∈ φ_range, λ ∈ λ_range]
    y = [sin(φ) * sin(λ) for φ ∈ φ_range, λ ∈ λ_range]
    z = [cos(λ) for φ ∈ φ_range, λ ∈ λ_range]
    @series begin
        # seriestype := :surface # this line does not work if you provide a surfce as set of points?
        x,y,z #plots a line per z value not a surface
    end
    seriestype --> :scatter
    return [p[1] for p ∈ pts], [p[2] for p ∈ pts], [p[3] for p ∈ pts]
end

M = Sphere(2)
pts = [ [1.0, 0.0, 0.0], [0.0, 1.0, 0.0] ]
plot(M, pts)

what I would like the @series is something either similar to wireframe or surface (in the end I want to be able to activate one, the other or both).

Edit: Ah, I see, so what I would like to obtain is what Make(!) does when you call `surface(x,y,z). on those data generated above, I.e. a nice surface of the sphere. How can I do that in Plots? And don’t recipes also work for Make? But they are still so different?

5

So my main problem seems to be that the series can not be convinced to do a 3D sphere (half transparent as a surface or as a mesh, either would be fine – later I want to be able to activate one of those or both). The result could vor example be similar to the plots I do with exports and rendering (Asymptote) here.

So how can I get a surface sphere in a series here ? Neither :surface nor :wireframe as series typedo work.

6

I found the culprit: Ith works with plotly() as backend but not with gr().

edit: I opened an Issue here at Plots.jl.

1 Like