r - Knitr ignoring fig.pos?

Question

I am trying to insert a figure in a RMarkdown document but am having trouble getting it to appear in the right place. The figure below shows the problem: when using a figure caption, the figure appears at the top of the page rather than below the relevant paragraph in the document.

Here is the code for this minimum working example:

---
title: "Untitled"
author: "Author"
date: "27 February 2017"
output: 
  pdf_document:
    fig_cap: yes
    keep_tex: yes
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE, fig.pos= "h")
```

## R Markdown

This is an R Markdown document. Markdown is a simple formatting syntax for authoring HTML, PDF, and MS Word documents. For more details on using R Markdown see <http://rmarkdown.rstudio.com>.


ewpage

## Including Plots

You can also embed plots, for example:

```{r pressure, echo=FALSE, fig.cap = "Hello"}
plot(pressure)
```

Note that the `echo = FALSE` parameter was added to the code chunk to prevent printing of the R code that generated the plot.

And here is the relevant part of the LaTeX output; note that the fig.pos option is ignored:

You can also embed plots, for example:

egin{figure}
centering
includegraphics{test_files/figure-latex/pressure-1.pdf}
caption{Hello}
end{figure}

Note that the exttt{echo = FALSE} parameter was added to the code
chunk to prevent printing of the R code that generated the plot.

My set-up is described below. I'm pretty sure this worked in previous version of knitr, but I don't have a note of which version that might have been.

> sessionInfo()
R version 3.3.2 (2016-10-31)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows >= 8 x64 (build 9200)

locale:
[1] LC_COLLATE=English_United Kingdom.1252  LC_CTYPE=English_United Kingdom.1252   
[3] LC_MONETARY=English_United Kingdom.1252 LC_NUMERIC=C                           
[5] LC_TIME=English_United Kingdom.1252    

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

loaded via a namespace (and not attached):
 [1] backports_1.0.5 magrittr_1.5    rprojroot_1.2   htmltools_0.3.5 tools_3.3.2    
 [6] yaml_2.1.14     Rcpp_0.12.9     stringi_1.1.2   rmarkdown_1.3   knitr_1.15.1   
[11] stringr_1.2.0   digest_0.6.12   evaluate_0.10  

Answer 1

The chunk option fig.pos is only used when knitr thinks it has to write out a LaTeX figure environment instead of pure Markdown ![](), and it writes LaTeX only when a figure caption (fig.cap) is specified, and at least one of these options has been specified: fig.align, out.width, out.extra. If you want to force knitr to write LaTeX code for figures and use fig.pos, you may set the chunk option out.extra = ''.