allow using ggraph *without* attaching it

[maxheld83]

library(ggraph)
library(igraph)
graph <- igraph::graph_from_data_frame(highschool)

# Not specifying the layout - defaults to "auto"
g <- ggraph(graph) + 
  geom_edge_link(aes(colour = factor(year))) + 
  geom_node_point()
g

This is fine:

However, when plotted without ggraph attached, the legend is missing and there are different colors.

detach(name = "package:ggraph", unload = TRUE)
g  # without legend

I am (wildly) guessing this has something to do with the black magic of the edge aesthetics that ggraph does.

This is not a problem in a script use (where usually you'd have library(ggraph)), but it can be a little odd in in-package use:
I'd rather not import the entire ggraph namespace, but without that, my examples on ggraph-derivative functions will not work properly (as in the above).

The behavior also strikes me as a little unexpected because, class(g) is only "gg" "ggplot", which makes me think that just ggplot::print.ggplot() ought to do the trick.

Is there any chance this could be changed?

[thomasp85]

This is unfortunately outside the hands of ggraph. It all boils down to how ggplot2 itself handles guides and legends. Currently it is looking on the search path for functions of the right name so you'll need to import these from ggraph in order to get it to work... hopefully the guide system will get an overhaul and adopt the ggproto approach someday, but as I said this is ggplot2 stuff, not ggraph

[maxheld83]

thanks so much for clarifying!

Do you have any recommendation for how to go about this if ggraph is used inside a package?

I have an autoplot method that uses ggraph, and I don't want to Imports: ggraph in the DESCRIPTION, because it's a rare use case.

So for now, I just remind users to library(ggraph) when they use this particular autoplot method.