munch

‘munch’ crunches markdown text and ‘flextable’ paragraphs into grid graphics.

‘munch’ started as internal code in ‘flextable’ for rendering rich text with ‘grid’. It was extracted into its own package to also serve ‘ggiraph’ and to provide unified formatting between ‘ggplot2’ graphics and ‘flextable’ tables.

‘munch’ lets you produce this annotated graphic:

The title, subtitle, caption and axis labels above are all built with element_chunks() and ‘flextable’ paragraph objects, bold, italic, colors, highlights, superscripts, subscripts, strikethrough and an embedded image.

Function	Purpose	Input
element_md()	Markdown in theme elements	Character string
element_chunks()	Advanced formatting in theme elements	as_paragraph() object
geom_text_md()	Markdown text annotations	label aesthetic
geom_label_md()	Markdown labels with background	label aesthetic

Installation

# install.packages("pak")
pak::pak("ardata-fr/munch")

Supported graphics devices

‘munch’ requires graphics devices that support ‘systemfonts’: ‘ragg’, ‘svglite’, or ‘ggiraph’. ‘cairo’ devices is also supported when fonts are installed at the system level. See vignette("font-recipes") for font configuration, alternative devices, and troubleshooting.

Quick start

ggplot2

Use element_md() for markdown in theme elements, and geom_text_md() or geom_label_md() for annotations:

library(ggplot2)

ggplot(mtcars, aes(mpg, wt)) +
 geom_point() +
 labs(title = "**Fuel consumption** vs *Weight*") +
 theme(plot.title = element_md(size = 16))

For advanced formatting (superscripts, subscripts, colors), use element_chunks() with ‘flextable’ paragraph objects:

title_chunks <- as_paragraph(
 as_chunk("Model: R"), as_sup("2"), as_chunk(" = 0.75")
)

ggplot(mtcars, aes(mpg, wt)) +
 geom_point() +
 theme(plot.title = element_chunks(title_chunks))

Syntax comparison

Syntax	element_md()	element_chunks()
Bold / Italic	**text** / *text*	as_b() / as_i()
Inline code	`code`	x
Strikethrough	~~text~~	as_strike()
Superscript	x	as_sup()
Subscript	x	as_sub()
Custom colors	x	colorize()
Highlighting	x	as_highlight()

Patchwork integration

Use munch_annotation() as a drop in replacement for patchwork::plot_annotation() which accepts element_chunk() and element_md() to add rich-text titles, subtitles, and captions — including auto-wrapping — to combined plots:

library(ggplot2)
library(patchwork)

p1 <- ggplot(mtcars, aes(mpg, wt)) +
  geom_point() +
  labs(x = "MPG", y = "Weight")

p2 <- ggplot(mtcars, aes(hp, wt)) +
  geom_point() +
  labs(x = "Horsepower", y = "Weight")

title_chunks <- as_paragraph(
  as_b("Motor Trend"), as_chunk(" — engine performance, 1974")
)

caption_chunks <- as_paragraph(
  as_chunk("R"), as_sup("2"), as_chunk(" = 0.75 · "),
  as_i("Lorem ipsum dolor sit amet, ut platea nullam odio dui in. "),
  as_i("Placerat gravida. Pretium phasellus non, dolor suscipit at aliquet, "),
  as_i("mollis venenatis per. Mus leo ante ligula.")
)

wrap_plots(p1, p2) +
  munch_annotation(
    title   = element_chunks(title_chunks),
    caption = element_chunks(caption_chunks, lineheight = 1.5, hjust = 0)
  )

For plain markdown text, pass the content as a string and use element_md() in the theme argument — the same pattern as regular ggplot2 theming:

wrap_plots(p1, p2) +
  munch_annotation(
    title   = "**Motor Trend** — engine performance, 1974",
    caption = "R^2^ = 0.75 · *Lorem ipsum dolor sit amet, ut platea nullam odio dui in. Placerat gravida pretium phasellus non, dolor suscipit at aliquet.*",
    theme   = theme(
      plot.title   = element_md(),
      plot.caption = element_md(lineheight = 1.5, hjust = 0)
    )
  )

The caption auto-wraps to the full figure width at render time, so it works correctly regardless of output size. title, subtitle, and caption each accept an element_chunks() or element_md() object, a bare as_paragraph() object, or a plain character string.

flextable

Use as_paragraph_md() for markdown in table cells:

ft <- flextable(head(iris, 3))
ft <- mk_par(ft, j = 1, part = "header",
 value = as_paragraph_md("*Sepal* **Length**"))
autofit(ft)

Markdown to grob

library(munch)
library(grid)

gr <- md_grob("This is **bold** and *italic* text.")
grid.newpage()
grid.draw(gr)

For superscripts, subscripts, or colors not available in markdown, use ‘flextable’ chunks with chunks_grob():

library(flextable)

chunks <- as_paragraph(as_chunk("E = mc"), as_sup("2"))
gr <- chunks_grob(chunks)
grid.newpage()
grid.draw(gr)

Learn more

• Theming ggplot2 with munch - element_md(), element_chunks(), geom_text_md(), geom_label_md()
• Advanced usage - md_grob(), chunks_grob(), text properties, images
• Font recipes - font configuration, device compatibility, troubleshooting

Comparisons

‘gridtext’

‘gridtext’ by Claus O. Wilke (used by ‘ggtext’) renders formatted text via a subset of HTML/CSS. ‘munch’ takes a different approach: it uses markdown or ‘flextable’ chunks as input and relies on ‘systemfonts’ for text measurement.

	munch	gridtext
Input format	Markdown, flextable chunks	HTML / CSS subset
Superscript / subscript	Yes (as_sup(), as_sub())	Yes (<sup>, <sub>)
Custom colors / highlight	Yes (via colorize(), as_highlight())	Yes (via inline CSS)
Inline images	Yes	Yes
Text wrapping	Yes	Yes (textbox_grob())
Text measurement	TBD	TBD
Integration with ‘flextable’	Yes (shared chunk model)	No
Supported devices	‘ragg’, ‘svglite’, ‘ggiraph’, cairo	Most R graphic devices
Compiled code	No (pure R)	Yes (C++ via ‘Rcpp’)

with ‘marquee’

‘marquee’ by Thomas Lin Pedersen offers more markdown features (headings, lists, code blocks, custom spans). ‘munch’ focuses first on integration with ‘flextable’ chunks and advanced formatting not available in markdown.

• ‘munch’ works with ‘ragg’, ‘svglite’, ‘ggiraph’, cairo_pdf(), png(type = "cairo"), eventually pdf() with few cautions.
• ‘marquee’ works on a wide range of R devices but not yet with ‘svglite’ or ‘ggiraph’.
• If working with markdown, ‘munch’ expect only a single paragraph, ‘marquee’ can handle many markdown blocks in one call.