As I mentioned earlier I’ve wanted to use otf-fonts in ggplot2-graphics

Rmd-Files

The next step is to use them in Knitr‘s RMarkdown-documents. That’s simple: Just use it as I showed earlier.

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title: "demo"
output: html_document

```{r}
 library(ggplot2)

 ggplot(mtcars, aes(x=wt, y=mpg, color=factor(gear))) + geom_point() +
  ggtitle("Fuel Efficiency of 32 Cars") +
  xlab("Weight (x1000 lb)") + ylab("Miles per Gallon") +
  theme(text=element_text(size=16, family="Source Code Pro"))
```

output

Rnw-Files

But using these fonts in Rnw-files — that’s embedded R-code in LaTeX-files — seems to be a little more complex.

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\documentclass{article}
 
\begin{document}
 
< <message=FALSE, echo=FALSE>>=
Sys.setenv(LANG = "en")
library(ggplot2, quietly=TRUE)
 
ggplot(mtcars, aes(x=wt, y=mpg, color=factor(gear))) + geom_point() +
  ggtitle("Fuel Efficiency of 32 Cars") +
  xlab("Weight (x1000 lb)") + ylab("Miles per Gallon") +
  theme(text=element_text(family="Source Code Pro"))
@
\end{document}

This document produces an error:

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Error in grid.Call.graphics(L_text, as.graphicsAnnot(x$label), x$x, x$y,  : 
  invalid font type
Calls: knit ... drawDetails -> drawDetails.text -> grid.Call.graphics
In addition: There were 50 or more warnings (use warnings() to see the first 50)

So I was looking for a work around.

Using Cairo

I’ve found the Cairo-device.

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\documentclass{article}
 
\begin{document}
<<>>=
Sys.setenv(LANG = "en")
library(Cairo)
library(ggplot2, quietly=TRUE)
@
 
<<message=FALSE, echo=FALSE, dev='cairo_pdf'>>=
ggplot(mtcars, aes(x=wt, y=mpg, color=factor(gear))) + geom_point() +
  ggtitle("Fuel Efficiency of 32 Cars") +
  xlab("Weight (x1000 lb)") + ylab("Miles per Gallon") +
  theme(text=element_text(family="Source Code Pro"))
@
 
\end{document}

But this generates lots of warnings.

1

## Warning in grid.Call(LtextBounds, as.graphicsAnnot(x$label), x$x,x$y, :  font family 'Source Code Pro' not found in PostScript fontdatabase

So I suppress warnings in the ggplot-chunk:

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\documentclass{article}
 
\begin{document}
<<>>=
Sys.setenv(LANG = "en")
library(Cairo)
library(ggplot2, quietly=TRUE)
@
 
<<message=FALSE, echo=FALSE, dev='cairo_pdf', warning=FALSE>>=
ggplot(mtcars, aes(x=wt, y=mpg, color=factor(gear))) + geom_point() +
  ggtitle("Fuel Efficiency of 32 Cars") +
  xlab("Weight (x1000 lb)") + ylab("Miles per Gallon") +
  theme(text=element_text(family="Source Code Pro"))
@
 
 
\end{document}

and tata:

output of Rnw-file with ggplot