Width of R code chunk output in RMarkdown files knitr-ed to html

Question

Question:

What is the current working solution to set the width of r code output in html files? I would like to set width to something big and use a slider in the

Answer 1

You can use this to make the pre blocks scroll horizontally if it overflows.

---
title: "Width test"
output:
  html_document:
    theme: default
---

<style>
pre {
  overflow-x: auto;
}
pre code {
  word-wrap: normal;
  white-space: pre;
}
</style>

```{r global_options, echo = FALSE, include = FALSE}
options(width = 999)
knitr::opts_chunk$set(echo = FALSE, warning = FALSE, message = FALSE,
                      cache = FALSE, tidy = FALSE, size = "small")
```
```{r}
sessionInfo()
```
```{r}
dataM <- matrix(rnorm(100, 5, 2), ncol = 20)
dataM
```

---

For a scrollable height, create a container div with a max height and a overflow-y: auto; or overflow-y: scroll;

Similar question/answer

---
title: "Height test"
output:
  html_document:
    theme: default
---

<style>
.pre-scrolly {
  max-height: 150px;
  overflow-y: auto;
}
</style>

<div class='pre-scrolly'>
```{r}
sessionInfo()
```
</div>

Answer 2

I ran into a similar problem but was using the Stata engine (more info here). In this case it turned out that it wasn't a problem with knitr itself but with my Stata settings.

The trick was to add a Stata-specific block after the initial setup block that sets the line width.

```{r setup_knitr, echo=FALSE, message=FALSE}
# This is the usual setup block needed to set up the Stata Engine
require(knitr)
statapath <- "C:/Program Files (x86)/Stata13/Stata-64.exe"
opts_chunk$set(engine="stata", engine.path=statapath, comment="")
``` 

```{r setup_stata, echo=FALSE,message=FALSE,collectcode=TRUE}
* Now that Stata engine is set up, this block sets up Stata options
set linesize 200
set more off
```

Answer 3

You could reset width and max-width using custom CSS e.g. like this:

---
title: "Width test"
output:
  html_document:
    theme: default
---
<style>
.main-container { width: 1200px; max-width:2800px;}
</style>

```{r global_options, echo = FALSE, include = FALSE}
options(width = 999)
knitr::opts_chunk$set(echo = FALSE, warning = FALSE, message = FALSE,
                      cache = FALSE, tidy = FALSE, size = "small")

```{r}
sessionInfo()
```
```{r}
dataM <- matrix(rnorm(100, 5, 2), ncol = 15)
dataM
```