[Rd] UTF8 markdown vignette

Yihui Xie xie at yihui.name
Tue Dec 9 17:13:10 CET 2014

A few things to clarify:

1. You do not necessarily have to keep the \usepackage{} line if you
use %\VignetteEncoding{UTF-8}, because Pandoc will use UTF-8 anyway in
its LaTeX template.

2. Perhaps the vignette engine in R has done something clever to
convert utf8 to UTF-8, but I'd recommend %\VignetteEncoding{UTF-8}
instead of %\VignetteEncoding{utf8} to make sure it is a valid
encoding name, e.g.

> 'utf8' %in% iconvlist()
> 'UTF-8' %in% iconvlist()
[1] TRUE
> 'UTF8' %in% iconvlist()
[1] TRUE

BTW, %\VignetteEncoding is not documented anywhere (Cc'ing Kurt), and
I think it needs to be documented, since the old approach
\usepackage[enc]{inputenc} was basically a hack, which looks really
odd in non-LaTeX vignettes (e.g. HTML vignettes).

3. The default `encoding` argument of rmarkdown::render() is not
relevant here, even if its value is native.enc. When R build a
vignette, it tries to detect its encoding and pass it to the vignette
engine, so the default argument value may not be native.enc.

Lastly, the most important piece of information is missing in this
post: library(rmarkdown); sessionInfo(). There is not a minimal
reproducible example, either. Without these information, I can only
guess blindly.

BTW, you may also try HTML vignettes instead, which is much much
easier to get right than LaTeX in terms of character encodings.

Yihui Xie <xieyihui at gmail.com>
Web: http://yihui.name

On Tue, Dec 9, 2014 at 7:05 AM, Duncan Murdoch <murdoch.duncan at gmail.com> wrote:
> On 09/12/2014, 5:19 AM, ONKELINX, Thierry wrote:
>> Dear Duncan,
>> The UTF-8 characters aren't properly rendered in the pdf version of the vignette.
>> $£€ âêîûô äëïöüÿ áéíóúý àèìòù ãñ çµ is rendered as $£€ âêîûô äëïöüÿ áéà óúý à èìòù ãñçµ
> That looks as though the UTF-8 characters are being interpreted as
> Latin1 characters (or whatever your native encoding is on Windows) when
> read from the file.
> It is quite tricky to work with UTF-8 in R in Windows.  I think Sweave
> does it properly, though there may be exceptions.  The issue is that
> many character input routines assume characters start out in the native
> encoding.  (There's also a translation that happens by default on
> output, but I don't think that's your problem.)  So the way to debug
> this is to follow all of the I/O, and see where the misinterpretation
> happens.  For vignettes, things are complicated, because R reads the
> file to determine which vignette engine to use, then the vignette engine
> reads it (perhaps more than once).
>> The same problem occurs when I use render("vignette.md", output_format = "mypackage::mystyle"), instead of render("vignette.md", output_format = "mypackage::mystyle", encoding = "UTF-8"). The default value of the encoding argument of rmarkdown::render() is
> encoding = getOption("encoding"), which is "native.enc" on my system.
> It sounds as though the render function needs a way to determine the
> encoding from the file itself.  Recent Sweave versions support the
> declaration
> %\VignetteEncoding{utf8}
> as well as the older
> \usepackage[utf8]{inputenc}
> that you used.  You might want to try that line as well.  (You need to
> keep the \usepackage line to tell LaTeX what encoding you're using.)
> Duncan Murdoch
>> I'll post the question on an RStudio forum as well.
>> Best regards,
>> Thierry
>> -----Oorspronkelijk bericht-----
>> Van: Duncan Murdoch [mailto:murdoch.duncan at gmail.com]
>> Verzonden: dinsdag 9 december 2014 11:04
>> Aan: ONKELINX, Thierry; r-devel at r-project.org
>> Onderwerp: Re: [Rd] UTF8 markdown vignette
>> On 09/12/2014, 4:48 AM, ONKELINX, Thierry wrote:
>>> Dear all,
>>> I'm trying to use a Markdown vignette with UTF-8 encoding. It compiles well when knitting the vignette in RStudio, but it fails to recognize the UTF-8 settings when building the source package. Can someone point out what I'm doing wrong? I tried to put the relevant information below.
>> You don't describe the symptoms of "failing to recognize", but from the look of it, this is a problem with the knitr::rmarkdown engine or with the devtools packaging, so you should probably ask on an RStudio forum.
>> Duncan Murdoch
>>> Best regards,
>>> Thierry
>>> Details:
>>> Using 64-bit R 3.1.2 with encoding = "native.enc" on Windows 7 with Rstudio 0.97.1091.
>>> The source packages is build using the devtools package. The build
>>> command is R --vanilla CMD build  "myPackage" --no-manual
>>> --no-resave-data
>>> The DESCRIPTION file has
>>> VignetteBuilder: knitr
>>> Suggests: knitr
>>> Imports: rmarkdown
>>> The markdown vignette YAML contains
>>> vignette: >
>>>   %\VignetteEngine{knitr::rmarkdown}
>>>   %\VignetteIndexEntry{The title}
>>>   \usepackage[utf8]{inputenc}
>>> The custom output style converts the markdown to beamer with the --latex-engine = xelatex flag.
>>> The vignette in tar.gz passes R --vanilla CMD check  --timings
>>> --as-cran
>>> * checking files in 'vignettes' ... OK
>>> * checking for unstated dependencies in vignettes ... OK
>>> * checking package vignettes in 'inst/doc' ... OK
>>> * checking running R code from vignettes ...
>>>    'markdown_intro.Rmd' using 'UTF-8' ... OK OK
>>> * checking re-building of vignette outputs ... [22s] OK

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