Transparent ggplot2 Plot Backgrounds

1 min read notes

While I was preparing a figure for a research poster recently, I ran into an issue: my poster had an off-white background but the figure had a white background.

The first thing that came to mind was making the plot background transparent. Should be easy enough?

It is.

The gist is that you need to set the both panel and and plot backgrounds to transparent. It’s probably a good idea to “turn off” the grid elements since otherwise they will default to a color. All of the above can be done with options via the theme() function.

And when saving the plot with ggsave() you also should indicate that the background is transparent.

library(ggplot2)
data("airquality")

p <- 
    ggplot(airquality, aes(Solar.R, Temp)) +
    geom_point() +
    geom_smooth() +
    # set transparency
    theme(
        panel.grid.major = element_blank(), 
        panel.grid.minor = element_blank(),
        panel.background = element_rect(fill = "transparent",colour = NA),
        plot.background = element_rect(fill = "transparent",colour = NA)
        )

p

ggsave("airquality.png", p, bg = "transparent")
ggplot2 R

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