How to Change Font Size of Text and Axes on R Plots
R provides multiple ways to customize the font size of text and axes in plots, enabling users to improve plot readability and presentation. Here’s how you can adjust these settings:
1. Using cex Parameter
The cex parameter controls the size of text elements relative to the default size.
- cex.main: Adjusts the title size.
- cex.lab: Adjusts the axis label size.
- cex.axis: Adjusts the tick mark label size.
- cex.sub: Adjusts the subtitle size.
Example:
plot(1:10, main = "Main Title", xlab = "X-axis", ylab = "Y-axis",
cex.main = 1.5, cex.lab = 1.2, cex.axis = 1, cex.sub = 0.8)
2. Using par() Function
The par() function can set graphical parameters globally before creating a plot.
par(cex.main = 1.5, cex.lab = 1.2, cex.axis = 1)
plot(1:10, main = "Main Title", xlab = "X-axis", ylab = "Y-axis")
3. Customizing Font Size with ggplot2
For ggplot2 users, font sizes can be customized using the theme() function.
Example:
library(ggplot2)
ggplot(mtcars, aes(x = wt, y = mpg)) +
geom_point() +
labs(title = "Title", x = "X-axis", y = "Y-axis") +
theme(plot.title = element_text(size = 16),
axis.title = element_text(size = 14),
axis.text = element_text(size = 12))
4. Using text() for Custom Text
To add custom text elements to a plot, use text() with the cex parameter.
plot(1:10)text(5, 8, "Custom Text", cex = 2)
Key Takeaways
- Use cex for base R plots and theme() for ggplot2 to adjust font sizes.
- par() can set global font size preferences in base R.
Customize sizes for individual plot elements (title, axis labels, tick marks) for precise control.