Measure text — vl_strwidth • vellum

vl_strwidth() / vl_strheight() return the rendered width/height of each string, using the same shaping (textshaping/HarfBuzz + systemfonts) the renderer uses, so measurements match drawn text. Device-independent (does not need an open scene). Vectorised over label. (Named vl_* to avoid masking grDevices::strwidth().)

Usage

vl_strwidth(
  label,
  family = "",
  fontface = "plain",
  fontsize = 12,
  cex = 1,
  unit = "in",
  features = NULL
)

vl_strheight(
  label,
  family = "",
  fontface = "plain",
  fontsize = 12,
  cex = 1,
  unit = "in",
  features = NULL
)

Arguments

label: Character vector of strings to measure, or a rich label from md() (or a list of them). Rich labels are measured with the same run composition the renderer draws, so super/subscripts and bold runs are accounted for; family/fontface/fontsize then supply the base style the label's runs are relative to.
family: Font family (e.g. "sans", "serif", "mono", or a specific family name). "" uses the system default.
fontface: One of "plain", "bold", "italic", "bold.italic".
fontsize: Font size in points.
cex: Multiplier applied to fontsize.
unit: Output unit: one of "in", "pt", "mm", "cm".
features: OpenType features as a named vector of four-character tags (e.g. c(tnum = 1)), matching vl_gpar()'s features. Measurement must use the same features as drawing, or reserved space will not match.

Value

A numeric vector (one per label) of widths/heights in unit.

Examples

vl_strwidth(c("short", "a longer label"), fontsize = 14)
#> [1] 0.499566 1.332248