fontquiver installs a set of fonts with permissive licences. It is useful for packages that needs controlled versions of fonts.
Get the development version from github with:
# install.packages("devtools")
devtools::install_github("lionel-/fontquiver")fontquiver is an interface to fonts installed as R packages. It
provides convenient and structured access, for instance, to the
Bitstream Vera font family installed with the fontBitstreamVera
package, or the Liberation family that comes with fontLiberation.
The fonts too heavy to be distributed on CRAN can be accessed by
fontquiver through Github-only packages such as fontDejaVu. Each
package bundles a set of fonts (or fontset as they are
called in fontquiver) which typically includes bold and italic faces for
sans and serif fonts, but may also include more exotic variations
(condensed, ultra light, etc). Call fontset_list() to check
which fontsets are currently installed on your computer.
Fonts installed in the R library can be useful for a variety of
purposes. They can be used in web applications with the
htmlFontDependency() tool. They are also helpful to create
reproducible outputs. An example of this is the vdiffr
package which relies on fontquiver to create SVGs that are reproducible
across platforms. Without fontquiver fonts, the SVGs generated by
svglite would have slight differences depending on the versions of the
system fonts used to compute text metrics.
The standard categories of fonts in R are the sans,
serif, and mono families and the
plain, italic, bold, and
bolditalic faces. However, font nomenclatures are extremely
rich and go well beyond those 12 categories. For example the DéjàVu set
contains a font whose variant and style are Serif Condensed
and Extra Light. For this reason, fontquiver uses the
categories provided by the font util fc-scan from Fontconfig.
The terms “variants” and “styles” refer to those categories while
“families” and “faces” refer to R’s categories.
To check which variants and styles are available for a given fontset:
fontset_variants("DejaVu")
fontset_styles("Bitstream Vera", variant = "Serif")fontquiver provides several getters to access font objects. They all
take a fontset name as argument. They may also take
variant/style or
family/face arguments.
font() takes a fontest, a variant and a style, and
returns an atomic font object. Those objects contain fields such as
ttf, fullname, or version:
font("Bitstream Vera", "Sans", "Roman")
font("Bitstream Vera", "Serif", "Bold")$ttfThe other getters return collections of fonts.
font_variants() returns a tree of lists with the outer list
containing all variants of a fontset and the inner lists containing all
styles for a given variant. Similarly, font_families()
returns a tree of fonts structured according to families and faces:
font_variants("Liberation")
font_families("Liberation")If you need a specific variant or family, font styles()
and font_faces() return a list of fonts:
font_styles("DejaVu", "Sans Condensed")
font_faces("DejaVu", "Mono")The htmlFontDependency() tool takes any font object or
collection of font objects. It copies the relevant fonts in
woff format to a temporary directory and creates a CSS
linking to those fonts.
# install.packages("htmltools")
# Create font dependency
liberation <- font_families("Liberation")
mono <- font_styles("DejaVu", "Sans Mono")
html_dep <- htmlFontDependency(liberation, mono)
span_mono <- htmltools::tags$span(
style = "font-family:'Deja Vu Sans Mono'; font-style:italic;",
"Text rendered with monospace italic font"
)
span_bold <- htmltools::tags$span(
style = "font-family:'Bitstream Vera Sans'; font-weight:700;",
"Text rendered with sans bold font"
)
# Add font dependency to an HTML object and print
text <- htmltools::div(span_mono, span_bold, html_dep)
htmltools::html_print(text)You can supply fontquiver fonts to svglite:
svglite::stringSVG(user_fonts = font_families("Liberation"), {
plot(1:10)
})See the fonts vignette in the svglite package for more about this.