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("r-lib/svglite") pak
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)
<- runif(1e3)
x <- runif(1e3)
y <- tempfile()
tmp1 <- tempfile()
tmp2
<- function() {
svglite_test svglite(tmp1)
plot(x, y)
dev.off()
}<- function() {
svg_test svg(tmp2, onefile = TRUE)
plot(x, y)
dev.off()
}
::mark(svglite_test(), svg_test(), min_iterations = 250, check = FALSE)
bench#> # 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() 2.64ms 2.73ms 362. 627KB 2.92
#> 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
::file_size(tmp1)
fs#> 75K
# svg
::file_size(tmp2)
fs#> 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.
<- tempfile(fileext = ".svgz")
tmp3 svglite(tmp3)
plot(x, y)
invisible(dev.off())
# svglite - svgz
::file_size(tmp3)
fs#> 9.46K
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.