Knitr ignoring fig.pos?

问题:

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>.

\newpage

## 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:

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

Note that the \texttt{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  

回答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 = ''.

回答2:

I know this was answered by Yihui Xie already but I have an alternative solution that avoids the need to include out.extra = '' or any of the other option that were given while also not interfering with figures that are rendered without captions.

Simply add the latex package 'float' and use the \floatplacement{figure}{H} to ensure every figure with a caption is rendered in proper order within the text as you wanted. Alternatively it could be added to the .tex file used when RMarkdown knits a pdf, but I am fairly new to this and haven't had time to look into that option myself.

I found this fix by looking at the .tex file in the thesisdown package from Chestar Ismay

It is a fairly easy fix by just adding three lines into the YAML. I don't have enough reputation to post a screen shot of it working but you can just copy what I've done and try it yourself!

---
title: "Untitled"
author: "Author"
date: "27 February 2017"
header-includes: #allows you to add in your own Latex packages
- \usepackage{float} #use the 'float' package
- \floatplacement{figure}{H} #make every figure with caption = h
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>.

\newpage

## 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.