Customizing ggplot for Multiple Page Layouts in a Single PDF

Introduction

In this article, we will explore how to create a single PDF file containing multiple pages of ggplots with different page layouts. We will discuss the use of gridExtra and ggsave functions in R, as well as provide examples and code snippets to help achieve this goal.

Understanding `gridExtra` and `ggsave`

The gridExtra package is used for creating complex layouts of plots. It allows us to arrange multiple plots into a single plot using the arrangeGrob function. The ggsave function, on the other hand, is used to save the arranged plot to a file.

Creating Multiple Page Layouts with Different Sizes

To create a single PDF file containing multiple pages of ggplots with different page layouts, we need to first create a list of plots for each page. Then, we use the arrangeGrob function to arrange these plots into separate plots for each page.

For example, let’s consider a scenario where we have three pages with different layout sizes: 2x2, 2x1, and 1x1.

# Create a list of plots for each page
pl <- lapply(1:7, function(i) ggplot() + ggtitle(i))

# Create separate plots for each page using arrangeGrob
ppl <- list(
  p1 = arrangeGrob(grobs=pl[1:4]),
  p2 = arrangeGrob(grobs=pl[5:6]),
  p3 = arrangeGrob(grobs=pl[7])
)

Using Class Tricking to Combine `arrangeGrob` and `ggsave`

One way to combine the use of arrangeGrob and ggsave is by using a class trick. We can create a new class, say “arrangelist”, that inherits from both “arrangeGrob” and “list”.

# Create a new class that combines arrangeGrob and list
class(ppl) <- c("arrangelist", class(pl))

# Use ggsave to save the combined plot
ggsave("multipage.pdf", ppl)

However, this approach has limitations. For instance, it does not work when we have multiple plots with different sizes in a single page.

Customizing ggplot for Multiple Page Layouts

To create a single PDF file containing multiple pages of ggplots with different page layouts, we can use the ggsave function and customize the plot using various options.

One common way to do this is by specifying the width and height arguments in the ggsave function. We can also use the landscape argument to display the plots in landscape mode.

Here’s an example code snippet that demonstrates how to create a single PDF file containing multiple pages of ggplots with different page layouts:

# Create a list of plots for each page
pl <- lapply(1:7, function(i) ggplot() + ggtitle(i))

# Create separate plots for each page using arrangeGrob
ppl <- list(
  p1 = arrangeGrob(grobs=pl[1:4], ncol=2),
  p2 = arrangeGrob(grobs=pl[5:6], ncol=1),
  p3 = arrangeGrob(grobs=pl[7], nrow=1)
)

# Customize the plot using ggsave
ggsave("multipage.pdf", width=11, height=8.5, landscape=true)

Conclusion

Creating a single PDF file containing multiple pages of ggplots with different page layouts can be achieved by using gridExtra and ggsave functions in R. By customizing the plot using various options such as specifying the width and height arguments or displaying the plots in landscape mode, we can create complex layouts of plots for publication.

In this article, we have discussed how to use arrangeGrob, ggsave, and class tricking to combine these functions. We also provided code snippets and examples to help achieve this goal.

Last modified on 2023-10-08