Introduction to gridmicrotex

What is gridmicrotex?

gridmicrotex renders LaTeX math equations as native R grid graphics objects (grobs). It uses the MicroTeX C++ library as its layout engine — MicroTeX parses LaTeX, builds the TeX box model, and computes exact glyph coordinates. The package intercepts this layout data and maps it to native grid primitives (pathGrob, segmentsGrob, rectGrob, textGrob), producing a gTree that works on any R graphics device at any resolution.

Key features:

• No external LaTeX installation required — MicroTeX is fully embedded
• Resolution-independent vector output on all R devices (PNG, PDF, SVG, …)
• Full math support: fractions, roots, integrals, matrices, Greek letters, accents, delimiters, and more
• Two bundled math fonts: Lete Sans Math (sans-serif, default) and STIX Two Math (serif); additional fonts via load_font()
• Color support via \textcolor{}
• ggplot2 integration with geom_latex() and element_latex()
• CJK and multilingual text in \text{} blocks

Basic usage

The core function is latex_grob(), which returns a grid grob:

g <- latex_grob("\\frac{-b \\pm \\sqrt{b^2 - 4ac}}{2a}", gp = grid::gpar(fontsize = 24))
grid::grid.newpage()
grid::grid.draw(g)

For quick rendering, use grid.latex():

grid::grid.newpage()
grid.latex("\\sum_{i=1}^{n} x_i^2", gp = grid::gpar(fontsize = 28))

Positioning and justification

Control placement with x, y, hjust, and vjust:

grid::grid.newpage()
grid.latex("Famous $E = mc^2$", x = 0.2, y = 0.7, hjust = 0, gp = grid::gpar(fontsize = 24))
grid.latex("F = ma", x = 0.2, y = 0.3, hjust = 0, gp = grid::gpar(fontsize = 24), input_mode = "math")

By default, the input is treated as LaTeX math mode, which treats string as text by default and use $...$ or \\(...\\) delimiters to render math. The "Famous" in the first equation above treated as text. The mixed mode converts the input to math mode to reduce the user burden for typing \\text{} and the conversion might not be perfect, but it should handle most common cases without user intervention. Use input_mode = "math" to treat the whole string as math mode (the second example) or if you find a problem with the conversion and render text with \\text{}. You can change this with global latex_options(input_mode = "math") for heavy math or users who wants to the advantages LaTex macros, etc. The vignette from next example will set the input mode to math globally and render the whole string as math mode.

Colors

You can use r"()" raw strings to write LaTeX with regular newlines and quotes without escaping. Set the formula color via gp, or use \textcolor{} within the LaTeX:

latex_options(input_mode = "math") # Set math mode globally
grid::grid.newpage()
grid.latex(
  r"(\textcolor{red}{\alpha} + \textcolor{blue}{\beta} = \gamma)",
  gp = grid::gpar(fontsize = 28)
)

Math fonts

The package ships with two math fonts, both loaded automatically:

available_math_fonts()
#> [1] "Lete Sans Math" "STIX Two Math"

latex_options(math_font = "stix")
grid::grid.newpage()
grid.latex(r"(\int_0^1 f(x)\,dx)", gp = grid::gpar(fontsize = 24))

# Switch back to the default (Lete Sans Math)
latex_options(math_font = "lete")

You can also override the font per call via math_font:

grid::grid.newpage()
grid::pushViewport(grid::viewport(layout = grid::grid.layout(2, 1)))
grid::pushViewport(grid::viewport(layout.pos.row = 1))
grid.latex(r"(\int_0^1 f(x)\,dx)", gp = grid::gpar(fontsize = 24))
grid::upViewport()
grid::pushViewport(grid::viewport(layout.pos.row = 2))
grid.latex(r"(\int_0^1 f(x)\,dx)", gp = grid::gpar(fontsize = 24), math_font = "stix")
grid::upViewport(2)

Use available_math_fonts() to list loaded fonts and check_fonts() for a diagnostic report.

load_font("path/to/MyFont.otf")

# Default typeface mode (selectable text in PDF/SVG)
grid.latex("E = mc^2", gp = grid::gpar(fontsize = 24))

# Explicit path mode (works everywhere, but text is not selectable)
grid.latex("E = mc^2", gp = grid::gpar(fontsize = 24), render_mode = "path")

Querying dimensions

latex_dims() returns the bounding box of an expression:

dims <- latex_dims("\\frac{a}{b}", gp = grid::gpar(fontsize = 20))
dims
#> $width
#> [1] 7bigpts
#> 
#> $height
#> [1] 25bigpts
#> 
#> $depth
#> [1] 9bigpts
#> 
#> $baseline
#> [1] 9.36317294836044bigpts
#> 
#> $is_split
#> [1] FALSE

This is useful for layout calculations and ensuring labels fit.

Text rendering and CJK support

Text inside \text{} and \mbox{} is rendered using R’s standard text-rendering system. This means gp$fontfamily controls the font for all text content — Latin letters, CJK characters, Cyrillic, and any other script your R graphics device supports:

grid::grid.newpage()
grid.latex("x^2 + \\text{你好}", gp = grid::gpar(fontsize = 24, fontfamily = "sans"))

Any font available to R works: base families like "sans", "serif", "mono", or fonts registered via showtext / systemfonts.

grid::grid.newpage()
grid.latex(
  "\\text{Theorem: } \\forall x \\in \\mathbb{R},\\; x^2 \\geq 0",
  math_font = "stix",
  gp = grid::gpar(fontfamily = "serif", fontsize = 12)
)

Supported LaTeX

gridmicrotex uses the MicroTeX engine, which is a math formula renderer, not a full document typesetter. It covers the vast majority of math notation you would use in plots and figures, but does not attempt to replace a full LaTeX installation.

grid::grid.newpage()
grid.latex(paste0(
      "\\begin{array}{l}",
      "  \\forall\\varepsilon\\in\\mathbb{R}_+^*\\ \\exists\\eta>0",
      "\\ |x-x_0|\\leq\\eta\\Longrightarrow|f(x)-f(x_0)|\\leq\\varepsilon\\\\",
      "  \\det",
      "  \\begin{bmatrix}",
      "      a_{11}&a_{12}&\\cdots&a_{1n}\\\\",
      "      a_{21}&\\ddots&&\\vdots\\\\",
      "      \\vdots&&\\ddots&\\vdots\\\\",
      "      a_{n1}&\\cdots&\\cdots&a_{nn}",
      "  \\end{bmatrix}",
      "  \\overset{\\mathrm{def}}{=}\\sum_{\\sigma\\in\\mathfrak{S}_n}",
      "\\varepsilon(\\sigma)\\prod_{k=1}^n a_{k\\sigma(k)}\\\\",
      "  \\int_0^\\infty{x^{2n} e^{-a x^2}\\,dx} = \\frac{2n-1}{2a}",
      " \\int_0^\\infty{x^{2(n-1)} e^{-a x^2}\\,dx}",
      " = \\frac{(2n-1)!!}{2^{n+1}} \\sqrt{\\frac{\\pi}{a^{2n+1}}}\\\\",
      "\\end{array}"
), gp = grid::gpar(fontsize = 16))

grid::grid.newpage()

grid.latex(
  "
  \\newcolumntype{s}{>{\\color{#1234B6}}c}
\\begin{array}{|c|c|c|s|}
  \\hline
  \\rowcolor{Tan}\\multicolumn{4}{|c|}{\\textcolor{white}{\\bold{\\text{Table Head}}}}\\\\
  \\hline
  \\text{Matrix}&\\multicolumn{2}{|c|}{\\text{Multicolumns}}&\\text{Font size commands}\\\\
  \\hline
  \\begin{pmatrix}
      \\alpha_{11}&\\cdots&\\alpha_{1n}\\\\
      \\hdotsfor{3}\\\\
      \\alpha_{n1}&\\cdots&\\alpha_{nn}
  \\end{pmatrix}
  &\\large \\text{Left}&\\cellcolor{#00bde5}\\small \\textcolor{white}{\\text{\\bold{Right}}}
  &\\small \\text{small Small}\\\\
  \\hline
  \\multicolumn{4}{|c|}{\\text{Table Foot}}\\\\
  \\hline
\\end{array}
  ",
  gp = grid::gpar(fontsize = 22)
)

grid::grid.newpage()
grid.latex(
  "\\definecolor{gris}{gray}{0.9}
\\definecolor{noir}{rgb}{0,0,0}
\\definecolor{bleu}{rgb}{0,0,1}
\\fatalIfCmdConflict{false}
\\newcommand{\\pa}{\\left|}
\\begin{array}{c}
  \\LaTeX\\\\
  \\begin{split}
      |I_2| &= \\pa\\int_0^T\\psi(t)\\left\\{ u(a,t)-\\int_{\\gamma(t)}^a \\frac{d\\theta}{k} (\\theta,t) \\int_a^\\theta c(\\xi)
          u_t (\\xi,t)\\,d\\xi\\right\\}dt\\right|\\\\
      &\\le C_6 \\Bigg|\\pa f \\int_\\Omega \\pa\\widetilde{S}^{-1,0}_{a,-}
          W_2(\\Omega, \\Gamma_1)\\right|\\ \\right|\\left| |u|\\overset{\\circ}{\\to} W_2^{\\widetilde{A}}(\\Omega\\Gamma_r,T)\\right|\\Bigg|\\\\
      &\\\\
      &\\begin{pmatrix}
          \\alpha&\\beta&\\gamma&\\delta\\\\
          \\aleph&\\beth&\\gimel&\\daleth\\\\
          \\mathfrak{A}&\\mathfrak{B}&\\mathfrak{C}&\\mathfrak{D}\\\\
          \\boldsymbol{\\mathfrak{a}}&\\boldsymbol{\\mathfrak{b}}&\\boldsymbol{\\mathfrak{c}}&\\boldsymbol{\\mathfrak{d}}
      \\end{pmatrix}
      \\quad{(a+b)}^{\\frac{n}{2}}=\\sqrt{\\sum_{k=0}^n\\tbinom{n}{k}a^kb^{n-k}}\\quad
          \\Biggl(\\biggl(\\Bigl(\\bigl(()\\bigr)\\Bigr)\\biggr)\\Biggr)\\\\
      &\\forall\\varepsilon\\in\\mathbb{R}_+^*\\ \\exists\\eta>0\\ |x-x_0|\\leq\\eta\\Longrightarrow|f(x)-f(x_0)|\\leq\\varepsilon\\\\
      &\\det
      \\begin{bmatrix}
          a_{11}&a_{12}&\\cdots&a_{1n}\\\\
          a_{21}&\\ddots&&\\vdots\\\\
          \\vdots&&\\ddots&\\vdots\\\\
          a_{n1}&\\cdots&\\cdots&a_{nn}
      \\end{bmatrix}
      \\overset{\\mathrm{def}}{=}\\sum_{\\sigma\\in\\mathfrak{S}_n}\\varepsilon(\\sigma)\\prod_{k=1}^n a_{k\\sigma(k)}\\\\
      &\\Delta f(x,y)=\\frac{\\partial^2f}{\\partial x^2}+\\frac{\\partial^2f}{\\partial y^2}\\qquad\\qquad \\fcolorbox{noir}{gris}
          {n!\\underset{n\\rightarrow+\\infty}{\\sim} {\\left(\\frac{n}{e}\\right)}^n\\sqrt{2\\pi n}}\\\\
      &\\sideset{_\\alpha^\\beta}{_\\gamma^\\delta}{
      \\begin{pmatrix}
          a&b\\\\
          c&d
      \\end{pmatrix}}
      \\xrightarrow[T]{n\\pm i-j}\\sideset{^t}{}A\\xleftarrow{\\overrightarrow{u}\\wedge\\overrightarrow{v}}
          \\underleftrightarrow{\\iint_{\\mathds{R}^2}e^{-\\left(x^2+y^2\\right)}\\,\\mathrm{d}x\\mathrm{d}y}
  \\end{split}\\\\
  \\rotatebox{30}{\\sum_{n=1}^{+\\infty}}\\quad\\mbox{Mirror rorriM}\\reflectbox{\\mbox{Mirror rorriM}}
\\end{array}",
  gp = grid::gpar(fontsize = 22),
  render_mode = "path"
)

Project-wide defaults

latex_options() sets defaults for math_font and render_mode, used by latex_grob(), grid.latex(), latex_dims(), and latex_tree() whenever the corresponding argument is not supplied at the call site. Size is controlled at the grob level via gp$fontsize / gp$lineheight (see Basic usage).

latex_options(math_font = "stix", render_mode = "typeface")

# Later calls pick these up automatically
grid.latex("\\sum_{i=1}^{n} i^{2}", gp = grid::gpar(fontsize = 14))

# Query current settings
latex_options()

# Reset to built-in defaults
reset_latex_options()

Explicit arguments always win. Setting math_font via latex_options() also updates the MicroTeX engine default, so you don’t also need a separate font-setup call.

User-defined macros

define_macro() registers zero-argument shorthands that are expanded by text substitution before the expression reaches MicroTeX. Handy for recurring notation:

define_macro("RR", "\\mathbb{R}")
define_macro("eps", "\\varepsilon")

grid::grid.newpage()
grid.latex("\\forall \\eps > 0, \\eps \\in \\RR", gp = grid::gpar(fontsize = 24))

clear_macros()

Macro names must be ASCII letters. Expansion iterates to a fixed point, so macros can reference other macros. Use list_macros() to see currently registered ones, and clear_macros() (with no arguments) to drop them all.

Layout caching

Parsed layouts are memoised by (tex, fontsize, math_font, render_mode, ...). Re-drawing the same formula — for example, the same axis label across many plots — reuses the cached layout:

latex_cache_info()       # size / max_size / hits / misses
latex_cache_limit(1024)  # raise or lower the LRU capacity
latex_cache_clear()      # wipe the cache (e.g. after re-loading fonts)

Set the limit to 0 to disable caching entirely.

Introspecting a formula

latex_tree() returns the raw draw-record table plus bbox metadata, useful for debugging alignment, counting glyphs, or building custom grobs on top of the layout:

tr <- latex_tree("\\frac{a}{b}")
tr
#> <latex_tree>
#>   tex:         \frac{a}{b}
#>   render_mode: typeface
#>   bbox:        width=7.00  height=25.00  depth=9.00  baseline=0.63 (bigpts)
#>   records:     3
#>     glyph      2
#>     line       1
head(tr$records, 3)
#>    type         x      y glyph font_size   color    x2     y2 width height rx
#> 1 glyph 0.1890002  7.196  3628        14 #000000    NA     NA    NA     NA NA
#> 2  line 0.0000000 10.596    NA        NA #000000 7.392 10.596    NA     NA NA
#> 3 glyph 0.0000000 25.796  3629        14 #000000    NA     NA    NA     NA NA
#>   ry  lwd text font_style rotation path codepoint
#> 1 NA   NA <NA>         NA        0 NULL        NA
#> 2 NA 1.32 <NA>         NA        0 NULL        NA
#> 3 NA   NA <NA>         NA        0 NULL        NA
#>                                                                                           font_file
#> 1 C:/Users/alim/AppData/Local/Temp/RtmpSexqod/Rinst77001d7b6166/gridmicrotex/fonts/LeteSansMath.otf
#> 2                                                                                              <NA>
#> 3 C:/Users/alim/AppData/Local/Temp/RtmpSexqod/Rinst77001d7b6166/gridmicrotex/fonts/LeteSansMath.otf

Debug overlay

Pass debug = TRUE to latex_grob() / grid.latex() to overlay diagnostics on the rendered formula — the full bounding box (dashed gray), the baseline (solid red), and a dot at each draw record’s origin. Useful for checking vertical alignment between a formula and surrounding grobs:

grid::grid.newpage()
grid.latex("x^{2} + y_{i}", gp = grid::gpar(fontsize = 30), debug = TRUE)

Comparison with alternatives

Graphics backend

The default graphics device on Windows (windows()) and macOS (quartz()) may not find the bundled math fonts, producing warnings like:

font family not found in Windows font database

To avoid this, switch to a modern graphics backend that uses systemfonts for font resolution:

# For knitr / R Markdown --- add to your setup chunk:
knitr::opts_chunk$set(dev = "ragg_png")

# For interactive use:
options(device = function(...) ragg::agg_png(tempfile(fileext = ".png"), ...))

Recommended backends:

Alternatively, use render_mode = "path" to bypass font lookup entirely — glyphs are drawn as vector paths, which works on all devices but produces non-selectable text in PDF/SVG.