Changing font in PDF produced by rmarkdown

Question

I am producing reports using rmarkdown. When knitting a PDF

---
title: \"Untitled\"
output: pdf_document
---

I would like to specify the fo

Answer 1

The indentation in YAML options is meaningful. As the instructions point out "note that these options do not appear underneath the output section but rather appear at the top level along with title, author, etc.)". So,

---
output:
  pdf_document:
    latex_engine: xelatex
    sansfont: Calibri Light
---

will produce an unused argument error, while

---
output:
  pdf_document:
    latex_engine: xelatex
sansfont: Calibri Light
---

will do the job. In addition, LaTeX commands inserted after YAML seem to override it: so

---
output:
  pdf_document:
    latex_engine: xelatex
    sansfont: Calibri Light
---
\fontsize{12}{22}
\fontseries{b}
\selectfont

produces the PDF with default font, not Calibri, however, the font option is passed fine.