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 support 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("devtools")
devtools::install_github("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)
#> # A tibble: 2 x 6
#> expression min median `itr/sec` mem_alloc `gc/sec`
#> <bch:expr> <bch:tm> <bch:tm> <dbl> <bch:byt> <dbl>
#> 1 svglite_test() 3.31ms 3.87ms 247. 561KB 5.05
#> 2 svg_test() 10.57ms 12.19ms 76.3 177KB 1.24
Another point with high relevance when serving SVGs over the web is the
size. svglite()
produces much smaller files
# svglite
fs::file_size(tmp1)
#> 74.9K
# svg
fs::file_size(tmp2)
#> 321K
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"
extension.
tmp3 <- tempfile(fileext = ".svgz")
svglite(tmp3)
plot(x, y)
invisible(dev.off())
# svglite - svgz
fs::file_size(tmp3)
#> 9.38K
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. 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.
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.