https://github.com/stefano-meschiari/latex2exp
Use LaTeX in R graphics.
https://github.com/stefano-meschiari/latex2exp
cran ggplot2 latex latex-formulas plotmath-expressions r
Last synced: about 2 months ago
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Use LaTeX in R graphics.
- Host: GitHub
- URL: https://github.com/stefano-meschiari/latex2exp
- Owner: stefano-meschiari
- License: other
- Created: 2015-06-11T16:48:49.000Z (almost 10 years ago)
- Default Branch: main
- Last Pushed: 2024-08-16T17:51:46.000Z (9 months ago)
- Last Synced: 2025-03-28T13:05:18.259Z (about 2 months ago)
- Topics: cran, ggplot2, latex, latex-formulas, plotmath-expressions, r
- Language: R
- Homepage:
- Size: 12.5 MB
- Stars: 189
- Watchers: 10
- Forks: 10
- Open Issues: 9
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
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# latex2exp 
**latex2exp** is an R package that lets you use LaTeX in plots. It
parses and converts LaTeX to R’s custom [plotmath
expressions](http://stat.ethz.ch/R-manual/R-patched/library/grDevices/html/plotmath.html).
You can read the full documentation on the [package’s
website](https://stefano-meschiari.github.io/latex2exp).
Expressions returned by `latex2exp` can be used to create formatted text
and mathematical formulas and symbols to be rendered as axis labels,
annotations, legends, titles, etc. throughout R’s plotting system.
## Installation
Install this package from CRAN:
``` r
install.packages('latex2exp')
```
You can also install the development version from GitHub using
[devtools](http://cran.r-project.org/web/packages/devtools/index.html):
``` r
devtools::install_github('stefano-meschiari/latex2exp')
```
## Usage
The `TeX` function takes a LaTeX string, parses it, and returns the
closest [plotmath
expression](http://stat.ethz.ch/R-manual/R-patched/library/grDevices/html/plotmath.html)
suitable for use in graphics. The return value of `TeX()` can be used
anywhere a plotmath expression is accepted, including plot labels,
legends, and text for both base graphics and ggplot2.
Here’s a simple example:
``` r
# Use raw strings, no need to escape backslashes.
TeX(r"(\textbf{Euler's identity} is $e^{i\pi} + 1 = 0$.)")
```
In this example, `\textbf{}` is used to mark a fragment of text as bold,
`$` introduces inline math mode, `^{}` typesets its contents as
superscript, and `\pi` typesets the letter *π*.
Starting with R 4.0, it is recommended to use the new raw string literal
syntax (see `?Quotes`). The syntax looks like `r"(...)"`, where `...`
can contain any character sequence, including `\`.
Another option is to escape the backslash character (`\`) for LaTeX
commands, such that the command will be written as `\\command` rather
than `\command`. This will also work on versions of R older than 4.0:
``` r
# Equivalent to the previous code fragment.
# Use regular strings, but escape the backslashes.
TeX("\\textbf{Euler's identity} is $e^{i\\pi} + 1 = 0$.")
```
You can quickly preview what a translated LaTeX string would look like
by using `plot`:
``` r
plot(TeX(r'(A $\LaTeX$ formula: $\frac{2hc^2}{\lambda^5}\frac{1}{e^{\frac{hc}{\lambda k_B T}} - 1}$)'), cex=2, main="")
```
The following example shows plotting in base graphics:
``` r
x <- seq(0, 4, length.out=100)
alpha <- 1:5
plot(x, xlim=c(0, 4), ylim=c(0, 10),
xlab='x', ylab=TeX(r'($\alpha x^\alpha$, where $\alpha \in \{1 \ldots 5\}$)'),
type='n', main=TeX(r'(Using $\LaTeX$ for plotting in base graphics!)', bold=TRUE))
for (a in alpha) {
lines(x, a*x^a, col=a)
}
legend('topleft',
legend=TeX(sprintf(r'($\alpha = %d$)', alpha)),
lwd=1,
col=alpha)
```
This example shows plotting in [ggplot2](https://ggplot2.tidyverse.org):
``` r
x <- seq(0, 4, length.out=100)
alpha <- 1:5
data <- map_df(alpha, ~ tibble(v=.*x^., x=x, alpha=.))
p <- ggplot(data, aes(x=x, y=v, color=as.factor(alpha))) +
geom_line() +
ylab(TeX(r'($\alpha x^\alpha$, where $\alpha \in 1\ldots 5$)')) +
ggtitle(TeX(r'(Using $\LaTeX$ for plotting in ggplot2. I $\heartsuit$ ggplot!)')) +
coord_cartesian(ylim=c(-1, 10)) +
guides(color=guide_legend(title=NULL)) +
scale_color_discrete(labels=lapply(sprintf(r'($\alpha = %d$)', alpha), TeX))
# Note that ggplot2 legend labels must be lists of expressions, not vectors of expressions
print(p)
```
Here are a few examples of what you can do with **latex2exp**:
``` r
latex2exp_examples(cex=0.9)
```
## Supported LaTeX commands
[Table of supported
LaTeX](https://www.stefanom.io/latex2exp/articles/supported-commands.html)