How to make graphics with transparent background in R using ggplot2?

Question

I need to output ggplot2 graphics from R to PNG files with transparent background. Everything is ok with basic R graphics, but no transparency with ggplot2:

d <- rnorm(100) #generating random data

#this returns transparent png

png('tr_tst1.png',width=300,height=300,units="px",bg = "transparent")

boxplot(d)

dev.off()

df <- data.frame(y=d,x=1)

p <- ggplot(df) + stat_boxplot(aes(x = x,y=y)) 

p <- p + opts(

    panel.background = theme_rect(fill = "transparent",colour = NA), # or theme_blank()

    panel.grid.minor = theme_blank(), 

    panel.grid.major = theme_blank()

)

#returns white background

png('tr_tst2.png',width=300,height=300,units="px",bg = "transparent")

p

dev.off()

Is there any way to get a transparent background with ggplot2?

Answer 1

To make graphics with transparent background in ggplot2, you can use the plot.background argument in theme function as follows:

library("ggplot2")

d <- rnorm(100)

df <- data.frame(y=d,x=1)

p <- ggplot(df) + stat_boxplot(aes(x = x,y=y))

p <- p + theme(

  panel.background = element_rect(fill = "transparent",colour = NA),

  panel.grid.minor = element_blank(), 

  panel.grid.major = element_blank(),

  plot.background = element_rect(fill = "transparent",colour = NA)

)

png('tr_tst.png',width=300,height=300,units="px",bg = "transparent")

print(p)

dev.off()

Output: