grobMark: Look up a named anchor inside a LaTeX grob

In gridmicrotex: Native 'LaTeX' Math Rendering for Grid Graphics

Look up a named anchor inside a LaTeX grob

Description

Resolves a \mark{name} that was placed inside the LaTeX source to a pair of grid units in the grob's parent viewport. The returned units already account for the grob's viewport position and hjust/vjust, so you can pass them directly to grid drawing functions to anchor other graphics on parts of the formula.

Usage

grobMark(grob, name)

Arguments

grob	A latexgrob returned by latex_grob.
name	The mark name (the argument to \mark{...}).

Value

A list with elements x and y, each a unit. Mark coordinates are evaluated in the grob's parent viewport.

See Also

latex_grob

Examples

  g <- latex_grob(r"($a\mark{eq}^2 = b + c^2$)",
                  x = grid::unit(0.5, "npc"),
                  y = grid::unit(0.5, "npc"))
  grid::grid.newpage(); grid::grid.draw(g)
  mk <- grobMark(g, "eq")
  grid::grid.points(mk$x, mk$y, pch = 19,
                    gp = grid::gpar(col = "red"))

gridmicrotex documentation built on May 16, 2026, 5:06 p.m.