R: kable_as_image cannot find Ghostscript

Question

I'm re-running some R Markdown scripts that worked fine a month ago, but now kable_as_image is unable to find Ghostscript (yes, I'm on Windows 8). I get the following error message:

Error in kable_as_image(criteria.table,"Criteria",file_format="jpeg"): 
Ghostscript is required to read PDF on windows. Please download it here: https://ghostscript.com/

My computer still has Ghostscript, which runs fine when I open it up independently (I tried reinstalling Ghostscript; it didn't help). My guess is that the problem has something to do with R, RStudio, or a package being unable to find the Ghostscript.

I'm pretty sure I've upgraded R in the interim, and I'm currently on 3.4.3 with the latest versions of kableExtra and magick. I've also tried

Sys.setenv(R_GSCMD="C:/Program Files/gs/gs9.22/bin/gswin64.exe")

(and also for gswin64c.exe) but that didn't help, either. Any advice would be appreciated.

Answer 1

Despite what the error message says, R needs the path to MikTeX (or your TeX program of choice), not to Ghostscript itself. The best solution is to add it to PATH in your operating system directly so it's always there, but it also works to add it within R. This is helpful to test it out before digging into your OS (make sure you have the right path), or if you don't have administrator privileges to your work machine.

Sys.setenv("PATH"=sprintf("%s;C:\\Users\\me\\AppData\\Local\\Programs\\MiKTeX 2.9\\miktex\\bin\\x64\\",Sys.getenv("PATH")))

Your path to MikTeX will likely be different than mine. Note that you need sprintf() or something similar to add the directory to the end of the PATH instead of overwriting the existing path.