Using ggplot2 with Julia pluto notebook - ggplot2

Question

I am working with a Pluto.jl notebook. I would like to use the ggplot2 R library to make some plots.
Following this example, if I run the following code in the Julia REPL then I can get a ggplot2 graph output.
using RCall
#rlibrary ggplot2
using DataFrames
df = DataFrame(v = [3,4,5], w = [5,6,7], x = [1,2,3], y = [4,5,6], z = [1,1,2])
ggplot(df, aes(x=:x,y=:y)) + geom_line()
Now, when I use the same code in a pluto.jl notebook (with each line being a separate cell), then I get the following error message:
Is there a way to get the ggplot2 image to appear inside the pluto notebook?
Similarly, if I just enter ggplot() into a cell, I get the same error, but ggplot not defined.

Answer 1

With #library Pluto.jl seems to be unable to find the R package.
However Pluto can handle this format:
#rimport ggplot2 as ggplot2
I managed to see the picture after clicking the "play" button 3 or 4 times. That is the end of good news - the Plut-RCall integration is kind of unstable. The graph shows in a separate Window that seems to hang - this is perhaps a story for opening an issue.
However what you can try to do is to save the image to a file and than visualize it:
begin
ggplot2.ggplot(df, ggplot2.aes(x=:x, y=:y)) + ggplot2.geom_line()
ggplot2.ggsave("myplot.png")
im1 = Images.load("myplot.png")
end

Answer 2

As a workaround, it is possible to override Base.show manually (see Pluto.jl/sample/test1.jl) with
function Base.show(io::IO, ::MIME"image/png", p::RObject{VecSxp})
(path, _) = mktemp()
R"ggsave($path, plot=$p, device = 'png')"
im = read(path)
rm(path)
write(io, im)
end
After that, cells which output anything of the type RObject{VecSxp} will show a PNG image: