Register a font as a variant as an existing one — register

This function is a wrapper around register_font() that allows you to easily create variants of existing system fonts, e.g. to target different weights and/or widths, or for attaching OpenType features to a font.

Usage

register_variant(
  name,
  family,
  weight = NULL,
  width = NULL,
  features = font_feature()
)

Arguments

name: The new family name the variant should respond to
family: The name of an existing font family that this is a variant of
weight: One or two of "thin", "ultralight", "light", "normal", "medium", "semibold", "bold", "ultrabold", or "heavy". If one is given it sets the weight for the whole variant. If two is given the first one defines the plain weight and the second the bold weight. If NULL then the variants of the given family closest to "normal" and "bold" will be chosen.
width: One of "ultracondensed", "extracondensed", "condensed", "semicondensed", "normal", "semiexpanded", "expanded", "extraexpanded", or "ultraexpanded" giving the width of the variant. If NULL then the width closest to "normal" will be chosen.
features: A font_feature object describing the specific OpenType font features to turn on for the registered font variant.

Font matching

During font matching, systemfonts has to look in three different locations. The font registry (populated by register_font()/register_variant()), the local fonts (populated with add_fonts()/scan_local_fonts()), and the fonts installed on the system. It does so in that order: registry > local > installed.

The matching performed at each step also differs. The fonts in the registry is only matched by family name. The local fonts are matched based on all the provided parameters (family, weight, italic, etc) in a way that is local to systemfonts, but try to emulate the system native matching. The installed fonts are matched using the system native matching functionality on macOS and Linux. On Windows the installed fonts are read from the system registry and matched using the same approach as for local fonts. Matching will always find a font no matter what you throw at it, defaulting to "sans" if nothing else is found.

Examples

# Get the default "sans" family
sans <- match_fonts("sans")$path
sans <- system_fonts()$family[system_fonts()$path == sans][1]

# Register a variant of it:
register_variant(
  "sans_ligature",
  sans,
  features = font_feature(ligatures = "discretionary")
)

registry_fonts()
#> # A tibble: 4 × 7
#>   path                        index family style weight italic features
#>   <chr>                       <int> <chr>  <chr> <ord>  <lgl>  <list>  
#> 1 /usr/share/fonts/truetype/…     0 sans_… Regu… normal FALSE  <int>   
#> 2 /usr/share/fonts/truetype/…     0 sans_… Bold  bold   FALSE  <int>   
#> 3 /usr/share/fonts/truetype/…     0 sans_… Ital… normal TRUE   <int>   
#> 4 /usr/share/fonts/truetype/…     0 sans_… Bold… bold   TRUE   <int>   

# clean up
clear_registry()