How to add ggproto objects together and save for later without call to ggplot()?

Question

I would like to save some specifications of a ggplot command for later, given that I need to run several different graphs that all share some scale aesthetics.

Let's say I would like save this for later:

my.scale_aes <- scale_x_continuous(...) + scale_color_manual(...) 

This would of course prompt an error message, indicating that you cannot add ggproto objects together without a direct ggplot() call. But is that really the case? And is there another way by which I could still add these components together?

I read somewhere else that it has to do with the different methods of adding elements together: methods("+") and that what I need has something to do with +.gg* but I have no idea how to implement this and how to make it work.

Answer 1

You can do this by defining a list of the ggplot terms you want and adding them in.

library(ggplot2)  my.scale_aes <- list(   scale_x_continuous(breaks = c(56, 60, 61)),   scale_color_manual(values = c("black", "red")) )  ggplot(data = diamonds[1:100,],        aes(depth, price, color = cut == "Ideal")) +   geom_point() +   my.scale_aes