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rpdfggplot2cran
Daniel
Daniel

Reputation: 1

No pdf written when using grid.arrange() together with pdf()

I am encountering a problem when saving a ggplot to pdf. I would like to plot two ggplot2 images side by side to a pdf using pdf(). However no content appears in the pdf. Is there any way to use grid.arrange() objects together with pdf()

Sample code to reproduce the problem:

    library(ggplot2)
    library(gridExtra)

    p1<-ggplot(mtcars, aes(mpg))+stat_ecdf()
    p2<-ggplot(mtcars, aes(cyl))+stat_ecdf()
    p3<-grid.arrange(p1,p2, ncol=2)

    pdf(file="plot.pdf")
    p3
    dev.off()

Upvotes: 0

Views: 260

Answers (1)

SamR
SamR

Reputation: 20444

When you call grid.arrange() it prints the plot but it does not return the plot. It returns a gtable object:

class(p3)
# [1] "gtable" "gTree"  "grob"   "gDesc"

If you try to print it you will see that:

p3
# TableGrob (1 x 2) "arrange": 2 grobs
#   z     cells    name           grob
# 1 1 (1-1,1-1) arrange gtable[layout]
# 2 2 (1-1,2-2) arrange gtable[layout]

If you want to write the plot to a pdf, you can do:

pdf(file="plot.pdf")
grid.arrange(p1,p2, ncol=2)
dev.off()

Upvotes: 1

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