CDN font support for Mathjax

NEWS.md

@@ -1,6 +1,6 @@
 # pkgdown (development version)
 
-* Support for math rendering using katex (`math-rendering: katex`) was improved and now includes necessary components using CDN (#2704).
+* Support for math rendering using katex and mathjax was improved and now includes necessary components using CDN (#2704).
 * Articles (i.e., Rmarkdown/Quarto documents in `vignettes/articles`, created by `usethis::use_article()` and available on pkgdown sites but not included in a built package) have improved test cases (thanks to @venpopov and @ethanbass).
 * New `clean_site(force = TRUE)` for cleaning of `docs/` regardless of whether it was built by pkgdown (#2827).
 * Links to favicons in page headers were updated to reflect changes to https://realfavicongenerator.net/ (#2804). Favicons should be re-generated by manually removing the `pkgdown/favicon` directory and then running `pkgdown::build_favicons()`.

R/render.R

@@ -128,6 +128,7 @@ data_template <- function(pkg = ".", depth = 0L) {
   out$footer <- data_footer(pkg)
   out$lightswitch <- uses_lightswitch(pkg)
   out$uses_katex <- config_math_rendering(pkg) == "katex"
+  out$uses_mathjax <- config_math_rendering(pkg) == "mathjax"
 
   print_yaml(out)
 }

inst/BS5/templates/head.html

@@ -20,6 +20,17 @@
 <script src="{{#site}}{{root}}{{/site}}katex-auto.js"></script>
 {{/uses_katex}}
 
+{{#uses_mathjax}}
+<!-- mathjax math fonts -->
+<script>
+  window.MathJax = {
+    chtml: {
+      fontURL: "https://cdn.jsdelivr.net/npm/[email protected]/es5/output/chtml/fonts/woff-v2"
+    }
+  };
+</script>
+{{/uses_mathjax}}
+
 {{#lightswitch}}<script src="{{#site}}{{root}}{{/site}}lightswitch.js"></script>{{/lightswitch}}
 
 {{{headdeps}}}