Quick start

The ggtext package in R extends the text rendering capabilities of ggplot2, allowing for rich text formatting in plot elements.

It provides functions to render markdown and HTML text in ggplot2 plots, enabling more flexible and visually appealing text elements.

✍️ author → Claus O. Wilke

📘 documentation → github

⭐️ more than 600 stars on github

Installation

To get started with ggtext, you can install it from CRAN using the install.packages function:

install.packages("ggtext")

Basic usage

The ggtext package allows you to use markdown and HTML formatting in text elements of ggplot2 plots. Here’s a basic example:

In this example, we use HTML tags (span) in the subtitle to color specific words. The element_markdown() function in the theme() call enables the rendering of this formatted text.

library(ggplot2)
library(ggtext)

ggplot(mtcars, aes(wt, mpg)) +
  geom_point() +
  labs(
    title = "Car Weight vs. MPG",
    subtitle = "Relationship between <span style='color:blue;'>weight</span> and <span style='color:red;'>miles per gallon</span>"
  ) +
  theme(plot.subtitle = element_markdown())

Key features

→ Rich Text Formatting

You can use markdown and HTML to format text, including bold, italic, and colored text.

Example:

library(ggplot2)
library(ggtext)

ggplot(mtcars, aes(wt, mpg)) +
  geom_point() +
  labs(
    title = "Car Weight vs. MPG",
    subtitle = "**Bold text**, *italic text*, and <span style='color:#72874EFF;'>**colored text**</span>"
  ) +
  theme(plot.subtitle = element_markdown())

→ `ggtext` as a legend

Using ggtext, we can change the axis labels so that they are colored to match the bar colors:

Inline Coloring:
- color defines bar and text colors.
- name combines item_name and group with HTML tags for styling: **{item_name}** ({group}).
Theming:
- axis.text.y = element_markdown() applies HTML/CSS formatting to y-axis labels.

This has direct benefits:

No Legend Needed: Labels are color-matched to bars, making the plot intuitive.
Enhanced Visualization: Improved readability and aesthetics through direct color association.

library(tidyverse)
library(ggtext)
library(glue)

data <- tibble(
  item_name = c("Item A", "Item B", "Item C", "Item D"),
  group = c("Group 1", "Group 2", "Group 3", "Group 4"),
  value = c(-1.5, 1.0, 2.5, 4.0)
)

data %>%
  mutate(
    color = c("#FF5733", "#33FF57", "#3357FF", "#FF33FF"),
    name = glue("<i style='color:{color}'>**{item_name}**</i> ({group})"),
    name = fct_reorder(name, value)
  ) %>%
  ggplot(aes(value, name, fill = color)) +
  geom_col(alpha = 0.5) +
  scale_fill_identity() +
  labs(caption = "Adapted example from the ***{ggtext}*** documentation<br>(using made-up data)") +
  theme(
    axis.text.y = element_markdown(),
    plot.caption = element_markdown(lineheight = 1.2)
  )

→ Box around text

ggtext can be used to create boxes around your text in different styles:

geom_richtext(): Replaces the usual geom_text() to render the text in label with special formatting.
The label entries use:
- **bold** for bold text.
-   for line breaks.
-  for colored text.
-  and  for superscript and subscript.
-  for larger text.

This setup allows the plot to display text with mixed styles (e.g., bold, colored, italicized) and structured formats (e.g., line breaks, superscripts) within a single text label.

library(ggplot2)
library(tibble)
library(ggtext)

df <- tibble(
  label = c(
    "Another text **in bold.**",
    "Different linebreaks<br>Linebreaks<br><br>Double Linebreaks",
    "*y*<sup>3</sup> + 7*y* + *D*<sub>*j*</sub>",
    "More <span style='color:green'>green text **in bold.**</span><br>And *italicized text.*<br>
    And some <span style='font-size:16pt; color:purple'>large</span> text."
  ),
  x = c(.3, .2, .6, .8),
  y = c(.7, .3, .2, .4),
  hjust = c(0.5, 0, 1, 0.5),
  vjust = c(0.5, 1, 0.5, 0.5),
  angle = c(0, 10, 30, -30),
  color = c("black", "green", "black", "purple"),
  fill = c("ivory", "white", "lightgreen", "white")
)

ggplot(df) +
  aes(
    x, y,
    label = label, angle = angle, color = color, fill = fill,
    hjust = hjust, vjust = vjust
  ) +
  geom_richtext() +
  geom_point(color = "black", size = 1) +
  scale_color_identity() +
  scale_fill_identity() +
  xlim(0, 1) +
  ylim(0, 1)