Change Theme Color in ggplot2 Plot in R

A theme in ggplot2 is a collection of settings that control the non-data elements of the plot. These settings include things like background colors, grid lines, axis labels, and text sizes. we can use various theme-related functions to customize the appearance of your plots, including changing theme colors.

Using ggplot() Change Theme Color in ggplot2 Plot in R

The ggplot() method can be used to create a plot of the data points. The points can be specified in the aesthetic mappings of the ggplot() method, wherein the x and y coordinates represent the column vectors of the data frame to be plotted. 

Syntax:

ggplot(df, aes = )

Arguments : 

• df : The data frame to be plotted.
• aes : The aesthetic mappings.

1. Installing the ggplot2 package

The ggplot2 package in R can be downloaded and installed into the working space using the following command : 

install.packages("ggplot2")
library("ggplot2")

2. Plotting graph using ggplot()

To plot a graph firstly we have to create a data frame using data.frame() method and then that data we are plotting the graph and a component of geom_point() is added to represent the data values as points in the graph as seen in the output.

library(ggplot2)

data_frame1 = data.frame(x= c(2,4,3,1),
                         y = c(3,1,6,8))
                         
ggplot(data_frame1,aes(x = x , y =y)) + 
  geom_point()

Output:

3. Changing theme color based on the background panel 

The background color of the plot can be changed by using the theme function. It overrides the default theme parameters. The background theme can be changed using the following syntax : 

Syntax: theme( panel.background = element_rect(fill = , color = ))

Parameters:

• fill : The fill color for the rectangle
• color : border color
• size : border size

We are going to change the background color to green and the x-axis and y-axis color to blue using the panel.background in theme() method.

library(ggplot2)

data_frame1 = data.frame(x= c(2,4,3,1),
                         y = c(3,1,6,8))
                         
ggplot(data_frame1,aes(x = x , y =y)) + 
  geom_point()+
  theme(panel.background = element_rect(fill = 'green', color = 'blue'))

Output:

4. Changing theme color based on in-built themes

There are a large number of in-built themes in the ggplot which can be added as components to the existing plot. Let's try some of them: 

1. theme_linedraw()

This method is used to create black lines inside the plot.

library(ggplot2)

data_frame1 = data.frame(x= c(2,4,3,1),
                         y = c(3,1,6,8))

ggplot(data_frame1,aes(x = x , y =y)) + 
  geom_point()+
  theme_linedraw()

Output:

2. theme_minimal()

This theme is used to remove background annotations.

library(ggplot2)

data_frame1 = data.frame(x= c(2,4,3,1),
                         y = c(3,1,6,8))
                         
ggplot(data_frame1,aes(x = x , y =y)) + 
  geom_point()+
  theme_minimal()

Output:

3. theme_dark()

It is used to create a dark background theme, as a result of which the elements of the graph are better popped out.

library(ggplot2)

data_frame1 = data.frame(x= c(2,4,3,1),
                         y = c(3,1,6,8))

ggplot(data_frame1,aes(x = x , y =y)) + 
  geom_point()+
  theme_dark()

Output:

4. theme_void()

It is used to remove the background theme.

library(ggplot2)

data_frame1 = data.frame(x= c(2,4,3,1),
                         y = c(3,1,6,8))

ggplot(data_frame1,aes(x = x , y =y)) + 
  geom_point()+
  theme_void()

Output:

5. theme_light()

It is used to plot the data in the form of light gray lines and an axis.

library(ggplot2)

data_frame1 = data.frame(x= c(2,4,3,1),
                         y = c(3,1,6,8))

ggplot(data_frame1,aes(x = x , y =y)) + 
  geom_point()+
  theme_light()

Output:

4. Changing the color of plotted points in the plot

The geom_point() method takes as arguments the aesthetic mappings which can be used to modify the color of the points by specifying the color.

library(ggplot2)

data_frame1 = data.frame(x= c(2,4,3,1),
                         y = c(3,1,6,8))

ggplot(data_frame1,aes(x = x , y =y)) + 
  geom_point(aes(colour="red"))

Output:

In this article, we learned how to change theme color in the ggplot2 plot in R programming language.