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Improved text rendering for ggplot2.
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README.md

ggtext

Improved text rendering support for ggplot2, written by Claus O. Wilke

This package provides ggplot2 support for the gridtext package, which implements rich-text (basic HTML and Markdown) rendering for the grid graphics engine. It is a work in progress. Many obvious features are missing, and others have bugs or don’t work in corner cases.

Installation

devtools::install_github("clauswilke/ggtext")

Examples

Rich text formatting support is provided both in theme elements and via geoms.

Markdown in theme elements

The ggtext package defines a new theme element, element_markdown(), which behaves similarly to element_text() but renders the provided text as markdown/html. Note that word wrapping is disabled by element_markdown(). To start a new line, use the <br> tag or add two spaces before the end of a line.

library(ggplot2)
library(ggtext)

ggplot(iris, aes(Sepal.Length, Sepal.Width, color = Species)) +
  geom_point(size = 3) +
  scale_color_manual(
    name = NULL,
    values = c(setosa = "#0072B2", virginica = "#009E73", versicolor = "#D55E00"),
    labels = c(
      setosa = "<i style='color:#0072B2'>I. setosa</i>",
      virginica = "<i style='color:#009E73'>I. virginica</i>",
      versicolor = "<i style='color:#D55E00'>I. versicolor</i>")
  ) +
  labs(
    title = "**Fisher's *Iris* dataset**  
    <span style='font-size:11pt'>Sepal width vs. sepal length for three *Iris*
    species</span>",
    x = "Sepal length (cm)", y = "Sepal width (cm)"
  ) +
  theme_minimal() +
  theme(
    plot.title = element_markdown(lineheight = 1.1),
    legend.text = element_markdown(size = 11)
  )

Very basic support for the <img> tag exists, and it can be used, for example, to employ images as axis labels.

labels <- c(
  setosa = "<img src='https://upload.wikimedia.org/wikipedia/commons/thumb/8/86/Iris_setosa.JPG/180px-Iris_setosa.JPG'
    width='100' /><br>*I. setosa*",
  virginica = "<img src='https://upload.wikimedia.org/wikipedia/commons/thumb/3/38/Iris_virginica_-_NRCS.jpg/320px-Iris_virginica_-_NRCS.jpg'
    width='100' /><br>*I. virginica*",
  versicolor = "<img src='https://upload.wikimedia.org/wikipedia/commons/thumb/2/27/20140427Iris_versicolor1.jpg/320px-20140427Iris_versicolor1.jpg'
    width='100' /><br>*I. versicolor*"
)

ggplot(iris, aes(Species, Sepal.Width)) +
  geom_boxplot() +
  scale_x_discrete(
    name = NULL,
    labels = labels
  ) +
  theme(
    axis.text.x = element_markdown(color = "black", size = 11)
  )

Geoms

The geom geom_richtext() provides markdown/html labels. Unlike geom_label(), the labels can be rotated.

df <- data.frame(
  label = c(
    "Some text **in bold.**",
    "Linebreaks<br>Linebreaks<br>Linebreaks",
    "*x*<sup>2</sup> + 5*x* + *C*<sub>*i*</sub>",
    "Some <span style='color:blue'>blue text **in bold.**</span><br>And *italics text.*<br>
    And some <span style='font-size:18pt; color:black'>large</span> text."
  ),
  x = c(.2, .1, .5, .9),
  y = c(.8, .4, .1, .5),
  hjust = c(0.5, 0, 0, 1),
  vjust = c(0.5, 1, 0, 0.5),
  angle = c(0, 0, 45, -45),
  color = c("black", "blue", "black", "red"),
  fill = c("cornsilk", "white", "lightblue1", "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 = 2) +
  scale_color_identity() +
  scale_fill_identity() +
  xlim(0, 1) + ylim(0, 1)

Labels without frame or background are also possible.

ggplot(df) +
  aes(
    x, y, label = label, angle = angle, color = color,
    hjust = hjust, vjust = vjust
  ) +
  geom_richtext(
    fill = NA, label.color = NA, # remove background and outline
    label.padding = grid::unit(rep(0, 4), "pt") # remove padding
  ) +
  geom_point(color = "black", size = 2) +
  scale_color_identity() +
  xlim(0, 1) + ylim(0, 1)

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