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I have created a graph in which I inset another graph (both ggplot2 objects) via this command:

    vp=viewPort(...)
    print(ggplotobject1)
    print(ggplotobject2, vp=vp)

This works exactly how I'd like it to (one large graph with a custom small graph drawn in the area specified in viewPort).

The problem is that I need to use this combined graph later for arranging it with other plots again through:

grid.arrange(arrangeGrob(..))

Does anyone have an idea how I can store my combined graph as a grob?

Thank you very much indeed!

EDIT: Responding to baptiste here is a reproducible example:

library(ggplot2)
library(gtable)
library(grid)

data<-mtcars
main_plot<-ggplot(data,aes(hp,mpg,group=cyl))+
  geom_smooth(method="lm")+geom_point()+
  facet_grid(.~gear)
sub_plot<-ggplot(data,aes(disp,wt,color))+geom_point()

gtable_main<-ggplot_gtable(ggplot_build(main_plot))
gtable_sub<-ggplot_gtable(ggplot_build(sub_plot))
gtable_show_layout(gtable_main)
gtable_main2<-gtable_add_grob(gtable_main,gtable_sub,t=4,l=4,b=1,r=1) 
grid.draw(gtable_main2)

This produces the graph I want, but I fail to make the subplot the right size (it's supposed to be a small graph in the bottom left corner of the plot). This is probably really basic, but I haven't worked with gtable before and only a little bit with grid/gridExtra.

Thanks a lot!

Sandy Muspratt
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TheFaScient
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1 Answers1

2

you could use annotation_custom or edit the gtable instead of printing to different viewports.

gm <- ggplotGrob(main_plot)
gs <- ggplotGrob(sub_plot)

library(gtable)
library(grid)
panel.id <- 1
panel <- gm$layout[gm$layout$name == "panel",][panel.id,]

inset <- grobTree(gs, vp=viewport(width=unit(1,"in"), x=0.8, y=0.8,
                                  height=unit(1,"in")))
gm <- gtable_add_grob(gm, inset, l=panel$l, t=panel$t)
grid.newpage()
grid.draw(gm)

enter image description here

baptiste
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  • Thank you for your answer. I have tried with `annotation_custom`, but since it is a faceted graph, I get it repeated for each facet, which I don't want. Concerning the `gtable` editing, could you perhaps give me an example of how it would work? Unfortunately, I'm not yet experienced with gtables. Thanks again! – TheFaScient Oct 26 '15 at 07:25
  • Following your advice, I have worked on understanding `gtable`. I managed to do almost what I wanted, but I can't wrap my mind around how to make the "inset" graph the right size (the l,t,r,b is just for position, right?). Could you give me a hint? Thank you very much! – TheFaScient Oct 26 '15 at 15:13
  • please provide a minimal self-contained reproducible example – baptiste Oct 26 '15 at 18:33
  • baptiste, thank you very much for this! This was what I was looking for. So what did the trick was using `grobTree` on the inset to specify its viewport within the main plot, correct? Thank you very much - I'd give an upvote, but my reputation is not high enough yet. – TheFaScient Oct 27 '15 at 09:50
  • yep. there are other ways probably, but that seems to do the trick. – baptiste Oct 27 '15 at 09:59