无法使用 blogdown 在我的 .Rmd 帖子中添加 tikz 代码片段

Question

我刚刚开始使用blogdown，并使用模板Hugo-Xmin 创建了一个项目。在 RStudio 中，在 blogdown 中创建项目时，它创建了一些预定义的帖子，我正在编辑这个：

/content/post/2015-07-23-r-rmarkdown.Rmd

添加 tikz 图片

在this question和bookdown documentation on engines之后，我通过添加这个sn-p修改了上述文件：

This is a tikz picture:

```{r, echo=FALSE, engine='tikz', out.width='90%', fig.ext=if (knitr:::is_latex_output()) 'pdf' else 'png', fig.cap='Some caption.'}
\begin{tikzpicture}[scale=.7]
\draw [fill=gray!30,very thick] (0,-1) rectangle (5,1);
\draw [very thick] (5, 0) -- (13,0);
\node [below] at (2,-1) {\large Hello};
\node [below, align=center] at (0,-1) {\large Two\\ lines};
\end{tikzpicture}
```

帖子处理失败

一旦我保存（因为我打开了serve），而且在使用blogdown::build_site() 时，我会得到这个：

> blogdown::serve_site()
Rendering content/post/2015-07-23-r-rmarkdown.Rmd
This is pdfTeX, Version 3.14159265-2.6-1.40.19 (TeX Live 2018/W32TeX) (preloaded format=pdflatex)
 restricted \write18 enabled.
entering extended mode
Quitting from lines 49-55 (2015-07-23-r-rmarkdown.Rmd) 
Error: Failed to compile .\tikz53878cd6189.tex. See https://yihui.name/tinytex/r/#debugging for debugging tips.
Execution halted
Error in render_page(f) : 
  Failed to render 'content/post/2015-07-23-r-rmarkdown.Rmd'

---

疑难解答

我检查了我的引擎，发现 tikz 实际上是其中之一：

> names(knitr::knit_engines$get())
 [1] "awk"         "bash"        "coffee"      "gawk"        "groovy"      "haskell"     "lein"        "mysql"      
 [9] "node"        "octave"      "perl"        "psql"        "Rscript"     "ruby"        "sas"         "scala"      
[17] "sed"         "sh"          "stata"       "zsh"         "highlight"   "Rcpp"        "tikz"        "dot"        
[25] "c"           "fortran"     "fortran95"   "asy"         "cat"         "asis"        "stan"        "block"      
[33] "block2"      "js"          "css"         "sql"         "go"          "python"      "julia"       "theorem"    
[41] "lemma"       "corollary"   "proposition" "conjecture"  "definition"  "example"     "exercise"    "proof"      
[49] "remark"      "solution"  

文档说有些引擎是在bookdown而不是knitr中发货的，但我可以看到tikz在那里！所以我有引擎，但我仍然无法使用它。我做错了什么？

---

更多信息

会生成一个日志文件/content/post/texput.log 并报告有关失败的信息：

This is pdfTeX, Version 3.14159265-2.6-1.40.19 (TeX Live 2018/W32TeX) (preloaded format=pdflatex 2019.1.11)  25 FEB 2019 07:54
entering extended mode
 restricted \write18 enabled.
 %&-line parsing enabled.
**.\tikz3cac449b1071.tex

! Emergency stop.
<*> .\tikz3cac449b1071.tex

*** (job aborted, file error in nonstop mode)


Here is how much of TeX's memory you used:
 3 strings out of 492616
 115 string characters out of 6132768
 56950 words of memory out of 5000000
 4017 multiletter control sequences out of 15000+600000
 3640 words of font info for 14 fonts, out of 8000000 for 9000
 1141 hyphenation exceptions out of 8191
 0i,0n,0p,1b,6s stack positions out of 5000i,500n,10000p,200000b,80000s
!  ==> Fatal error occurred, no output PDF file produced!

如果我检查knitr:

> xfun::session_info('knitr')
R version 3.5.2 (2018-12-20)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows >= 8 x64 (build 9200), RStudio 1.1.463

Locale:
  LC_COLLATE=English_United States.1252  LC_CTYPE=English_United States.1252   
  LC_MONETARY=English_United States.1252 LC_NUMERIC=C                          
  LC_TIME=English_United States.1252    

Package version:
  evaluate_0.13   glue_1.3.0      graphics_3.5.2  grDevices_3.5.2 highr_0.7       knitr_1.21.13  
  magrittr_1.5    markdown_0.9    methods_3.5.2   mime_0.6        stats_3.5.2     stringi_1.3.1  
  stringr_1.4.0   tools_3.5.2     utils_3.5.2     xfun_0.5        yaml_2.2.0

Answer 1

这原来是 knitr 中的一个问题，它是 Github 上的 I just fixed（我不确定这是否是 pdflatex 的错误）。你可以试试

remotes::install_github('yihui/knitr')

请注意，如果尚未安装两个额外的 R 包，ma​​gick 和 pdftools，则需要安装它们。