Today's guest post comes from Winston Chang, a software developer at RStudio — ed. When it comes to making figures in R, you can use any font you like, as long as it's Helvetica, Times, or Courier. Using other fonts that are installed on your computer can seem an impossible task, especially if you want to save the output to PDF. Fortunately, the extrafont package makes this process much easier. With it, you can create beautiful, professional-looking results like this: When using fonts in PDF files, there are two challenges: First you must tell R that the font is available...