R tikzdevice: How to use sans serif font

Question

I'm using ggplot in R to create plots, tikzdevice to save them and then latex to compile them in a larger document.

when I create a very simple plot, eg

require(ggplot2)
require(tikzDevice)

tikz("test.tikz", height = 4, width = 4)
ggplot(data = data.frame(x = c(1:3), y = c(1:3)), aes(x=x, y=y)) +
geom_point() +
theme(text = element_text(family = "sans", face = "bold"))
dev.off()

While I can change the size and the font face using the element_text options in theme , changing the font family doesn't work. Ie the exported tikz does not contain the sans-serif command.

How can I export the graphic using sans-serif font for text (and particularly the axis labels)?

Answer 1

tikz() will output latex code. The fonts will be the ones specified in this latex document (which is great because that results in a consistent look).

Creating a standalone figure with sans-serif font that you can then render via pdflatex test.tikz can be achieved like this:

require(ggplot2)
require(tikzDevice)
options(tikzLatexPackages = 
      c(getOption("tikzLatexPackages"), 
        "\\renewcommand{\\familydefault}{\\sfdefault}\n")
      )

tikz("test.tikz", height = 4, width = 4, standAlone = TRUE)
   ggplot(data = data.frame(x = c(1:3), y = c(1:3)), aes(x=x, y=y)) +
   geom_point()
dev.off()

We pass in additional text that is written to the preamble via options . We need to add new options to the default options and not overwrite them, which is why we concatenate with getOption("tikzLatexPackages") . Also note that you have to escape \ in the R strings.

The second important part is to set standAlone = TRUE if we want to render the figure on its own and not make it part of a larger document.

How to set fonts in a latex document I still find somewhat mysterious. My solution builds on this question . But you could pass in other latex commands via options to set fonts in a different way.