This is a helper function for knitting Rmd. Due to technological limitation, the output cannot knit to PDF in Rmd directly (the problem is with the latex engine printing unicode character).
Therefore, to bypass this problem, you will first need to knit to html file first, then use this function to convert it to a PDF file.
html_to_pdf(file_path = NULL, dir = NULL, scale = 1, render_exist = FALSE)
file path to the HTML file (can be relative if you are in a R project)
file path to the directory of all HTML files (can be relative if you are in a R project)
the scale of the PDF
overwrite exist PDF. Default is FALSE
no return value
if (FALSE) {
html_to_pdf(file_path = "html_name.html")
# all HTML files in the my_html_folder will be converted
html_to_pdf(dir = "Users/Desktop/my_html_folder")
}