svglite is a graphics device that produces clean svg output, suitable
for use on the web, or hand editing. Compared to the built-in svg(),
svglite produces smaller files, and leaves text as is, making it easier
to edit the result after creation. It also supports multiple nice
features such as embedding of web fonts.
svglite is available on CRAN using install.packages("svglite"). You
can install the development version from github with:
# install.packages("pak") pak::pak("r-lib/svglite")
The grDevices package bundled with R already comes with an SVG device
(using the eponymous svg() call). The development of svglite is
motivated by the following considerations:
svglite() is considerably faster than svg(). If you are rendering
SVGs dynamically to serve over the web this can be quite important:
library(svglite) x <- runif(1e3) y <- runif(1e3) tmp1 <- tempfile() tmp2 <- tempfile() svglite_test <- function() { svglite(tmp1) plot(x, y) dev.off() } svg_test <- function() { svg(tmp2, onefile = TRUE) plot(x, y) dev.off() } bench::mark(svglite_test(), svg_test(), min_iterations = 250, check = FALSE) #> # A tibble: 2 × 6 #> expression min median `itr/sec` mem_alloc `gc/sec` #> <bch:expr> <bch:tm> <bch:tm> <dbl> <bch:byt> <dbl> #> 1 svglite_test() 2.86ms 2.97ms 325. 709KB 5.28 #> 2 svg_test() 6.11ms 6.26ms 159. 224KB 0.638
Another point with high relevance when serving SVGs over the web is the
size. svglite() produces much smaller files
# svglite fs::file_size(tmp1) #> 75K # svg fs::file_size(tmp2) #> 327K
In both cases, compressing to make .svgz (gzipped svg) is worthwhile.
svglite supports compressed output directly which will be triggered if
the provided path has a ".svgz" (or ".svg.gz") extension.
tmp3 <- tempfile(fileext = ".svgz") svglite(tmp3) plot(x, y) invisible(dev.off()) # svglite - svgz fs::file_size(tmp3) #> 9.45K
One of the main reasons for the size difference between the size of the
output of svglite() and svg() is the fact that svglite() encodes
text as styled <text> elements, whereas svg() converts the glyphs to
polygons and renders these. The latter approach means that the output of
svg() does not require the font to be present on the system that
displays the SVG but makes it more or less impossible to edit the text
after the fact. svglite focuses on providing maximal editability of the
output, so that you can open up the result in a vector drawing program
such as Inkscape or Illustrator and polish the output if you so choose.
svglite uses systemfonts for font discovery which means that all
installed fonts on your system is available to use. The systemfonts
foundation means that fonts registered with register_font() or
register_variant() will also be available, as will fonts added with
add_fonts() and require_font(). If any of these contains
non-standard weights or OpenType features (e.g. ligatures or tabular
numerics) this will be correctly encoded in the style block. systemfonts
also allows you to embed webfont @imports in your file to ensure that
the file looks as expected even on systems without the used font
installed. Using systemfonts::fonts_as_import() you can generate these
imports automatically, optionally embedding the font data directly in
the file.
This section is only relevant for building svglite from scratch, as opposed to installing from a pre-built package on CRAN.
Building svglite requires the system dependency libpng. As svglite
doesn’t have any build-time configuration, your R configuration must
point to libpng’s include and lib folders.
For instance on macOS, install libpng with:
brew install libpng
And make sure your ~/.R/Makevars knows about Homebrew’s include and
lib folders where libpng should now be installed. On arm64 hardware,
this would be:
CPPFLAGS += -I/opt/homebrew/include LDFLAGS += -L/opt/homebrew/lib
Please note that the svglite project is released with a Contributor Code of Conduct. By contributing to this project, you agree to abide by its terms.