Size a unit by a grob's extent

grobwidth(grob) and grobheight(grob) return a vl_unit() equal to the drawn width/height of grob — handy for sizing a vl_viewport() or grid_layout() track to its contents (e.g. a margin to an axis label). The extent is measured eagerly to absolute millimetres at construction, so it is exact for text and absolute-unit (mm/in/pt) grobs. A grob sized in npc/native has no viewport-independent extent and is measured against a fixed reference, so for those prefer npc/native directly.

Usage

grobwidth(grob, mult = 1)

grobheight(grob, mult = 1)

Arguments

grob

A grob (or composite subtree) to measure.

mult

A multiplier on the measured extent (default 1).

Value

A unit (in millimetres).

Examples

grobwidth(text_grob("A wide axis label", gp = vl_gpar(fontsize = 14)))
#> <vellum_unit[1]>
#> [1] 41.51753mm
grobheight(rect_grob(height = vl_unit(8, "mm")))
#> <vellum_unit[1]>
#> [1] 8.466667mm