Display method for in-text accidentals

[mccarthy-m-g]

Displaying sharps, flats, and other music symbols in-text is an important feature for this book. Although I could write sharps with # and flats with b, this is less accurate and attractive than using the ♯ and ♭ music symbols. So far I have found two options for rendering these music symbols in bookdown:

1. Mathjax.
2. Unicode, as I'm doing in this post.

Both methods support some of the symbols I need, however, I've encountered problems implementing them (see below). Any help or alternate suggestions would be appreciated.

Mathjax problems

• Mathjax does not allow me to prepend a music symbol to plain text (e.g., ♭3); a space must exist between the music symbol and the plain text.
  • This code $\flat$3 does not work in the body of my document, it renders like $$3.
  • A workaround for this, following the example code, is to include the 3 within the equation (i.e., $\flat 3$).
  • However, doing this will force me to use Mathjax's renderer for alphanumeric characters and superscripting, which will complicate the writing process. And Mathjax only seems to support the basic Tex font in bookdown, which clashes with the appearance of the HTML version's typeface.
  • It is possible to use a sans-serif font with Mathjax using the following code $\sf 3$, however this doesn't support boldface.

Unicode problems

• Only the most basic rendering is available; size, boldface, etc., are not available.
• The symbols only seem to render in HTML versions, not PDFs. This means unicode isn't a viable option unless I use different symbols for the HTML and PDF versions.

Using different renderers for different outputs

I could use different renderers for HTML and PDF if the best solutions are HTML or PDF specific. If I have to go this route there is the musicography package for LaTex I could use (assuming it can be installed in my GitHub actions build; I'd have to figure that out).

[mccarthy-m-g]

This commit solves this issue. For anyone curious: I chose to use different renderers for HTML and PDF outputs, and will be using inline R code to reference symbols. For example: `r f` will display a flat symbol using unicode in the HTML version and the musicography package in the LaTeX version.

The only downside to this approach is that:

1. I have to create a new R object whenever I want to include a new symbol.
2. I have to source() the _musicSymbols.R file containing the music symbol R objects at the start of any chapter I wish to use them in. This appears to be a limitation of the knitr::is_html_output() and knitr::is_latex_output() functions, as their documentation says they only work in .Rmd files. Calling _musicSymbols.R in _bookdown.yml with before_chapter_script: does not work.
3. The Bravura Text font doesn't seem to work in the epub version of this book.
4. The current implantation leaves symbols invisible while the font loads (I can change the css to uncomment font-display: swap; to change this behaviour though).