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Inspect the parsed layout of a LaTeX expression

Source: R/latex-tree.R
latex_tree.Rd

Returns the raw draw-record table produced by MicroTeX's layout pass together with the bounding-box metadata. Useful for debugging alignment issues, building custom grobs on top of the layout, or counting glyphs/paths/rules in a formula.

Usage

latex_tree(
  tex,
  math_font = "",
  max_width = 0,
  tex_style = "",
  input_mode = c("mixed", "math"),
  render_mode = c("typeface", "path"),
  gp = grid::gpar()
)

Arguments

tex

Character string of LaTeX math code.

math_font

Name of the math font to use (e.g., "stix"). Use "" (default) for Lete Sans Math, which pairs with R's default sans-serif text font. See available_math_fonts for loaded fonts.

max_width

Numeric maximum width in big points for automatic line wrapping. Use 0 (default) for no wrapping.

tex_style

Character: TeX style override. One of "" (default; let the parser decide), "display", "text", "script", or "scriptscript". See latex_grob for the semantics of each value.

input_mode

How tex is interpreted before being parsed. "mixed" wraps the input in \text{...} so the string reads as ordinary text and $...$ (or \(...\)) opens math mode, matching document-level LaTeX semantics. Useful for labels that arrive from external sources mixing prose and math without explicit \text{} markers. "math" (default) is the standard MicroTeX behaviour — the whole string is treated as math, so unwrapped prose renders as spaced math italics. The default can be changed globally via latex_options(input_mode = "mixed"). See latex_wrap for details on the wrapping process.

render_mode

Character string: "typeface" (default) renders glyphs as native text using the math font, producing selectable/accessible text in PDF and SVG output. Bundled math fonts and any registered via load_font are read directly from their OTF files — no system-wide font install is required. Falls back to path mode automatically on devices that lack the R \(\geq\) 4.3 glyph engine (e.g., the base pdf() device). For selectable PDF output, prefer cairo_pdf. "path" renders math symbols as filled vector paths (works on all devices but text is not selectable in PDF/SVG).

gp

Graphical parameters (see gpar). Common entries: col (formula foreground), fontfamily / fontface (text font), fontsize / cex (formula size), and lineheight (multi-line spacing). See latex_grob for how each of these flows through MicroTeX.

Value

A list with class "latex_tree" containing:

records

Data frame of draw records (one row per glyph, path, line, rect, or text block). Columns include type, x, y, glyph, font_size, color, text, codepoint, font_file.

bbox

Named numeric vector with width, height, depth, baseline (all in big points).

tex

The (macro-expanded) input string.

render_mode

Rendering mode used for the layout.

See also

latex_grob, latex_dims

Examples

# \donttest{
  tree <- latex_tree("\\frac{a}{b}")
  print(tree)
#> <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(tree$records)
#>    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 /home/runner/work/_temp/Library/gridmicrotex/fonts/LeteSansMath.otf
#> 2                                                                <NA>
#> 3 /home/runner/work/_temp/Library/gridmicrotex/fonts/LeteSansMath.otf
# }