[R] display UTF8 characters in pdf

[Olivier CROUZET]

Hi,

AFAICT, you need to use a Cairo device for being able to display some 
Unicode
characters in a plot.

 From my experience, the CairoPDF() from library(Cairo) does not work
(and I don't understand the difference with cairo_pdf()), but the
cairo_pdf() from grDevices does work perfectly well for this aim. As far
as I'm concerned, I use it with both ggplot2 and regular plots and it
does a perfect job. Here is a short example:

In an R console:

cairo_pdf(filename = "test.pdf")
plot(1,1,pch = "\u254")
dev.off()

Also, I use it with knitr and it works great. You just have to declare a
specific device ("cairo_pdf").

For example, in an RMarkdown document:

```{r ipaunicode, echo=TRUE, dev='cairo_pdf'}
plot(1, 1, pch = "\u254")
```

and in a LaTeX / knitr document as well:

<<ipaunicode, dev="cairo_pdf">>=
plot(1, 1, pch = "\u251")
@

Hope this helps.

Yours.
Olivier.

On Fri, 10 Mar
2017 17:06:25 +0100 Thierry Onkelinx <thierry.onkelinx at inbo.be> wrote:

> Dear all,
> 
> I'd like to use some UTF-8 characters in a plot. Some of them are not
> rendered with saving the plot as pdf. Any suggestions?
> 
> library(ggplot2)
> symbols <- c("\U1F697", "\U00A9", "\U24DA", "\U00C1")
> test <- data.frame(
>   x = seq_along(symbols) %% ceiling(sqrt(length(symbols))),
>   y = ceiling(seq_along(symbols) / ceiling(sqrt(length(symbols)))),
>   symbol = symbols
> )
> p <- ggplot(test, aes(x = x, y = y, label = symbol)) + geom_text(size
> = 10) p
> ggsave(p, file = "test.png")
> ggsave(p, file = "test.pdf")
> 
> The last command gives several similar warnings, all related to the
> symbols which are not rendered properly:
> 
> Warning messages:
> 1: In grid.Call.graphics(L_text, as.graphicsAnnot(x$label),  ... :
>   conversion failure on '��' in 'mbcsToSbcs': dot substituted for <f0>
> 
> I'm running R 3.3.2 under Ubuntu 16.04.1 and ggplot2 2.2.1
> 
> Best regards,
> 
> Thierry
> 
> 
> ir. Thierry Onkelinx
> Instituut voor natuur- en bosonderzoek / Research Institute for
> Nature and Forest
> team Biometrie & Kwaliteitszorg / team Biometrics & Quality Assurance
> Kliniekstraat 25
> 1070 Anderlecht
> Belgium
> 
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> 
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-- 
   Olivier Crouzet, PhD
   /Assistant Professor/
   @LLING - Laboratoire de Linguistique de Nantes
     UMR6310 CNRS / Université de Nantes
   /Guest Researcher/
   @UMCG (University Medical Center Groningen)
     ENT department
     Reijksuniversiteit Groningen