Centering image and text in R Markdown for a PDF report

Question

I want to center an image and/or text using R Markdown and knit a PDF report out of it.

I have tried using:

->Text<-

->![](image1.jpg)<-

That does not do the trick! Any other way of getting this done?

Dakotadal

Answer 1

I had the same question. I have tried all solutions provided above and none of them worked... But I have found a solution that works for me, and hopefully for others too.

<center>

![your image caption](image.png)

</center>

This code will center both the image and the caption. It is essential that you leave lines between <center>, the image code, and </center>, otherwise the image will be centered but the caption will disappear.

If you want your image to have a clickable link, you can embed things like

[![your image caption](image.png)](www.link_to_image.com)

However, the caption will no longer appear.

So if you want a clickable caption you will have to do it in two steps:

<center>

![](image.png)

[your image caption](www.link_to_image.com)

</center>

Same here, make sure there are empty lines in between each command ones. If you want both the image and the caption to be clickable, then combine the middle and the last codes above. I hope this helps a bit.

Odontalgia

Most useful (please bold it): "It is essential that you leave lines between <center>, the image code, and </center>, otherwise the image will be centered but the caption will disappear." – Saratov

Nothing works for me.. considering too the warship clarification – Pentheam

this doesn't seem to work for PDF outputs, as requested by the OP. Maybe you could say that in your answer? – Hearst

it seems that you can't use this technique if you don't want a caption. – Motta

Answer 2

If you are centering the output of an R code chunk, e.g., a plot, then you can use the fig.align option in knitr.

```{r fig.align="center"}
plot(mtcars)
```

Synovia

Answer 3

You can use raw LaTeX in R Markdown. Try this:

\begin{center}
Text
\end{center}

There is, of course, a catch: everything between begin{...} and \end{...} is interpreted as raw LaTeX by Pandoc, so you can't use this technique to center the output of R code chunks, or Markdown content.

Knut

What if we want to center the output of R code chunks? – Snick

Any "special" new error is simply, as mentioned, that you can't use markdown or html anymore in there. Only LaTeX syntax allowed. As for R code chunks instead, they are actually super easy to place thanks to knitr's fig.align="center". – Pentagrid

This should be in BOLD : "so you can't use this technique to center the output of R code chunks, or Markdown content" I realized why I wasn't successful. – Grit

Answer 4

You can set the center (or other) alignment for the whole document as a Knitr option, using:

knitr::opts_chunk$set(echo = TRUE, fig.align="center")

Magniloquent

Answer 5

None of the answers work for all output types the same way and others focus on figures plottet within the code chunk and not external images.

The include_graphics() function provides an easy solution. The only argument is the name of the file (with the relative path if it's in a subfolder). By setting echo to FALSE and fig.align=center you get the wished result.

```{r, echo=FALSE, fig.align='center'}
include_graphics("image.jpg")
```

Grim

great solution! just want to add that this is from the knitr package, not the rmarkdown package if anyone uses this solution. – Loaf

Answer 6

I used the answer from Jonathan to google inserting images into LaTeX and if you would like to insert an image named image1.jpg and have it centered, your code might look like this in Rmarkdown

\begin{center}
\includegraphics{image1}
\end{center}

Keep in mind that LaTex is not asking for the file exention (.jpg). This question helped me get my answer. Thanks.

Joceline

Answer 7

The simple solution given by Jonathan works with a modification to cheat Pandoc. Instead of direct Latex commands such as

\begin{center}
Text
\end{center}

you can define your own commands in the YAML header:

header-includes:
- \newcommand{\bcenter}{\begin{center}}
- \newcommand{\ecenter}{\end{center}}

And then you use:

\bcenter
Text and more
\ecenter

This works for me for centering a whole document with many code chunks and markdown commands in between.

Homochromous

this works fantastically – Lewert

Answer 8

I'm using beamer to knit pdf from Rmarkdown and what worked for me is:

\centering
![](image1.jpg)

Hewett

Answer 9

If you know your format is PDF, then I don't see how the HTML tag can be useful... It definitely does not seem to work for me. The other pure LaTeX solutions obviously work just fine. But the whole point of Markdown is not to do LaTeX but to allow for multiple format compilation I believe, including HTML.

Therefore, with this in mind, what works for me is a variation of Nicolas Hamilton's answer to Color Text Stackoverflow question:

#############
## CENTER TXT
ctrFmt = function(x){
  if(out_type == 'latex' || out_type == 'beamer')
    paste0("\\begin{center}\n", x, "\n\\end{center}")
  else if(out_type == 'html')
    paste0("<center>\n", x, "\n</center>")
  else
    x
}

I put this inside my initial setup chunk. Then I use it very easily in my .rmd file:

`r ctrFmt("Centered text in html and pdf!")`

Surmise

Answer 10

There is now a much better solution, a lot more elegant, based on fenced div, which have been implemented in pandoc, as explained here:

::: {.center data-latex=""}
Some text here...
:::

All you need to do is to change your css file accordingly. The following chunk for instance does the job:

```{cat, engine.opts = list(file = "style.css")}
.center {
  text-align: center;
}
``` 

(Obviously, you can also directly type the content of the chunk into your .css file...).
The tex file includes the proper centering commands.
The crucial advantage of this method is that it allows writing markdown code inside the block.
In my previous answer, r ctrFmt("Centered **text** in html and pdf!") does not bold for the word "text", but it would if inside a fenced div.

For images, etc... the lua filter is available here

Surmise

Answer 11

Just to update the question. To do this some easy way, you can add fig.align="center" to the chunk with the chuck knitr options:

    knitr::opts_chunk$set(echo = TRUE,
                          fig.align="center" #align all the figures in the center
                          )

Substation

Answer 12

none of the answers worked but this

\newcommand{\bcenter}{\begin{center}}
\newcommand{\ecenter}{\end{center}}

but then the following problem is that it works for only one figure and then will not for any other figures.

I just started learning R I knew it was going to be difficult but what's worst is that there is little to no info that I can refer to.

Aindrea

Answer 13

None of these solutions worked for me when inserting a pdf figure in the text. After intensive trial and error, what made the trick for me (for a pdf output) was:

\hfil ![](image1.pdf) \hfil

Vicereine

Your answer could be improved with additional supporting information. Please edit to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers in the help center. – Charry

Answer 14

Since the question asks for both text and image alignment and I had a hard time finding an option for text that worked, with non of the ones above working withing a code chunk (for me). I wanted to share this: it seem to do the trick to the best of it's abilities (meaning it's not perfectly centered but close)

centerText <- function() {
  width <- getOption("width")
  out <- "your text"
  ws <- rep(" ", floor((width - nchar(out))/2))
  cat(ws, out, sep = "")
}
centerText()  

Original code comes from here

Karynkaryo

Answer 15

Hey here is the simple way which I found recently.

\center

image

\raggedright

text

This code worked for pdf file in the R markdown.

Gummous

Your answer could be improved with additional supporting information. Please edit to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers in the help center. – Charry