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

Last Updated : 14 Sep, 2021

In this article, we will discuss how to create graphs with transparent background in R programming language.

The required task will be achieved by using theme() function with appropriate parameters. theme() function used to modify theme settings. To actually visualize a transparent background the image has to be stored as a PNG image, this can be done ggsave() function.

Syntax: ggsave(plot, filename, bg)

Parameter:

plot: plot to be saved
filename: path of the file
bg: background

Create a simple plot for demonstration:

library(ggplot2)

function1<- function(x){x**2}
function2<-function(x){x**3}
function3<-function(x){x/2}
function4<-function(x){2*(x**3)+(x**2)-(x/2)}

df=data.frame(x=-2:2,
              values=c(function1(-2:2),
                       function2(-2:2),
                       function3(-2:2),
                       function4(-2:2)),
              fun=rep(c("function1","function2",
                        "function3","function4"))
)

plt<-ggplot(df,aes(x,values,col=fun))+geom_line()

ggsave(plt, filename = "output1.png")

Output:

Method 1: Using rect with theme()

In this approach, after the plot has been created normally, theme() function is added to it with rect parameter. To rect, element_rect() function is passed with parameter fill set to transparent.

Syntax: theme(rect = element_rect(fill="transparent"))

Example: Plot with transparent background

library(ggplot2)

function1<- function(x){x**2}
function2<-function(x){x**3}
function3<-function(x){x/2}
function4<-function(x){2*(x**3)+(x**2)-(x/2)}

df=data.frame(x=-2:2,
              values=c(function1(-2:2),
                       function2(-2:2),
                       function3(-2:2),
                       function4(-2:2)),
              fun=rep(c("function1","function2",
                        "function3","function4"))
)

plt<-ggplot(df,aes(x,values,col=fun))+geom_line()+
  theme(rect = element_rect(fill = "transparent"))

ggsave(plt, filename = "output.png", bg = "transparent")

Output:

Method 2: Setting each theme parameter separately

By setting, background elements to transparent the background of a plot can be made transparent.

Example: Plot with transparent background

library(ggplot2)

function1<- function(x){x**2}
function2<-function(x){x**3}
function3<-function(x){x/2}
function4<-function(x){2*(x**3)+(x**2)-(x/2)}

df=data.frame(x=-2:2,
              values=c(function1(-2:2),
                       function2(-2:2),
                       function3(-2:2),
                       function4(-2:2)),
              fun=rep(c("function1","function2",
                        "function3","function4"))
)

plt<-ggplot(df,aes(x,values,col=fun))+geom_line()+
  theme(legend.background = element_rect(fill = "transparent"),
        legend.box.background = element_rect(fill = "transparent"),
        panel.background = element_rect(fill = "transparent"),
        panel.grid.major = element_blank(),
        panel.grid.minor = element_blank(),
        plot.background = element_rect(fill = "transparent",
                                       color = NA))

ggsave(plt, filename = "output1.png", bg = "transparent")