ggplot list of plots to one pdf with different page layouts

Question

I want to produce a single pdf with many pages of ggplots. Using gridExtra, I can also build a page of plots with a m x n layout (m rows of plots, n columns of plots).

The function ggsave allows me to write a page of plots, even those that are built with gridExtra having the m x n layout.

Using arrangeGrob it is even possible to ggsave many pages to a single pdf, as long as each page has the same m x n layout.

I'm wondering how I can ggsave a list of plots that have different page layouts? For example, I have a list, l, with length 3 representing 3 pages.

l[[1]] is a page with a 2 x 2 layout and has 4 plots

l[[2]] is 2 x 1 with 2 plots

l[[3]] is only 1 x 1

How could I hack ggsave so that I can write the list l into 1 pdf file with 3 pages having different layouts? The plots should be displayed in landscape, so typically the command would have the form

ggsave("multipage.pdf", do.call(arrangeGrob, myplots[[i]]), width=11, height=8.5)

Answer 1

you can use the same class trick as marrangeGrob,

library(ggplot2)
library(gridExtra)
pl <- lapply(1:7, function(i) ggplot() + ggtitle(i))

ppl <- list(p1 = arrangeGrob(grobs=pl[1:4]),
            p2 = arrangeGrob(grobs=pl[5:6]),
            p3 = arrangeGrob(grobs=pl[7]))

class(ppl) <- c("arrangelist", class(pl))

ggsave("multipage.pdf", ppl)