From cc3351f5c101f9e8de19738b1dbc64a01ef9a64e Mon Sep 17 00:00:00 2001
From: Suzanne Soy <ligo@suzanne.soy>
Date: Sat, 27 Mar 2021 17:43:22 +0000
Subject: [PATCH] Added parameter for cusom KaTeX and MathJax locations

---
 dollar.rkt                      | 44 ++++++++++++++++++---------------
 scribblings/scribble-math.scrbl | 42 +++++++++++++++++++++++++++++++
 2 files changed, 66 insertions(+), 20 deletions(-)

diff --git a/dollar.rkt b/dollar.rkt
index 23de83f26..3a347c672 100644
--- a/dollar.rkt
+++ b/dollar.rkt
@@ -42,6 +42,10 @@
            $$-tex2svg
            use-tex2svg
            current-tex2svg-path))
+
+(define use-external-mathjax (make-parameter #f))
+(define use-external-katex (make-parameter #f))
+
 ;; KaTeX does not work well with the HTML 4.01 Transitional loose DTD,
 ;; so we define a style modifier which replaces the prefix for HTML rendering.
 (define (with-html5 doc-style)
@@ -148,11 +152,11 @@ EOJS
    ;; <script type="text/x-mathjax-config">
    ;;   MathJax.Hub.Config({ tex2jax: {inlineMath: [['$','$']]} });
    ;; </script>
-   (load-script-string "MathJax/MathJax.js?config=default")))
+   (load-script-string (or (use-external-mathjax) "MathJax/MathJax.js?config=default"))))
 
 #;(define load-mathjax-code
   (string->bytes/utf-8
-   (string-append (load-script-string "MathJax/MathJax.js?config=default")
+   (string-append (or (use-external-mathjax) "MathJax/MathJax.js?config=default")
                   #<<EOJS
 (function(f) {
   // A "simple" onLoad function
@@ -202,8 +206,8 @@ EOJS
 
 (define load-katex-code+style
   (string->bytes/utf-8
-   (string-append (load-style-string "katex/katex.min.css")
-                  (load-script-string "katex/katex.min.js")
+   (string-append (load-style-string (if (use-external-katex) (cadr (use-external-katex)) "katex/katex.min.css"))
+                  (load-script-string (if (use-external-katex) (car (use-external-katex)) "katex/katex.min.js"))
                   #<<EOJS
 (function(f) {
   // A "simple" onLoad function
@@ -269,31 +273,31 @@ EOTEX
 
 (define math-inline-style-mathjax
   (style "math"
-         (list (alt-tag "span")
-               #;(make-css-addition math-inline.css)
-               (install-resource mathjax-dir)
-               (js-addition load-mathjax-code)
-               'exact-chars)))
+         (append (list (alt-tag "span"))
+                 #;(list (make-css-addition math-inline.css))
+                 (if (use-external-mathjax) '() (list (install-resource mathjax-dir)))
+                 (list (js-addition load-mathjax-code))
+                 (list 'exact-chars))))
 
 (define math-display-style-mathjax
   (style "math"
-         (list (alt-tag "div")
-               #;(make-css-addition math-inline.css)
-               (install-resource mathjax-dir)
-               (js-addition load-mathjax-code)
-               'exact-chars)))
+         (append (list (alt-tag "div"))
+                 #;(list (make-css-addition math-inline.css))
+                 (if (use-external-mathjax) '() (list (install-resource mathjax-dir)))
+                 (list (js-addition load-mathjax-code))
+                 (list 'exact-chars))))
 
 (define math-inline-style-katex
   (style "texMathInline"
-         (list (install-resource katex-dir)
-               (js-addition load-katex-code+style)
-               'exact-chars)))
+         (append (if (use-external-katex) '() (list (install-resource katex-dir)))
+                 (list (js-addition load-katex-code+style))
+                 (list 'exact-chars))))
 
 (define math-display-style-katex
   (style "texMathDisplay"
-         (list (install-resource katex-dir)
-               (js-addition load-katex-code+style)
-               'exact-chars)))
+         (append (if (use-external-katex) '() (list (install-resource katex-dir)))
+                 (list (js-addition load-katex-code+style))
+                 (list 'exact-chars))))
 
 (define math-inline-style-latex
   (style "texMathInline"
diff --git a/scribblings/scribble-math.scrbl b/scribblings/scribble-math.scrbl
index c6b86505a..eae3b1875 100644
--- a/scribblings/scribble-math.scrbl
+++ b/scribblings/scribble-math.scrbl
@@ -279,6 +279,48 @@ details see the documentation of @racket[with-html5].
 
  This parameter requires Racket 6.12 or later.}
 
+@defparam[use-external-mathjax URL string? #:value #f]{
+                                                       
+ A parameter whose value is the URL to the MathJax script
+ to use. The URL must be absolute, or relative to the URL
+ used to display the document.
+
+ For example, if the HTML document is accessed via @tt{
+  file:///home/user/docs/document1/index.html}, and
+ @racket[(use-external-mathjax "../common/MathJax/MathJax.js?config=default")] was
+ used, then MathJax will be loaded from @tt{
+  file:///home/user/docs/common/MathJax/MathJax.js?config=default}.
+
+ An URL to a CDN is also valid, but may be a poor choice
+ regarding the privacy of your users.
+
+ This feature is in beta and might not work, please report
+ any issue.}
+
+@defparam[use-external-katex URLs (list/c string? string?) #:value #f]{
+                                                       
+ A parameter whose value is a list containing the URL to the
+ KaTeX script and the URL to KaTeX CSS to use. The URLs must
+ be absolute, or relative to the URL used to display the
+ document.
+
+ For example, if the HTML document is accessed via @tt{
+  file:///home/user/docs/document1/index.html}, and
+ @racket[(use-external-katex (list "../common/KaTeX/katex.min.js" "../common/KaTeX/katex.min.css"))]
+ was used, then the KaTeX script will be loaded from @tt{
+  file:///home/user/docs/common/KaTeX/katex.min.js} and the
+ KaTeX stylesheet from @tt{
+  file:///home/user/docs/common/KaTeX/katex.min.css}.
+
+ An URL to a CDN is also valid, but may be a poor choice
+ regarding the privacy of your users.
+
+ Please note that using a .js and a .css file which are not
+ in the same directory is unsupported (it has not been tested
+ and may or may not work).
+
+ This feature is in beta and might not work, please report
+ any issue.}
 
 @;@$${\sum_{i=0}ⁿ xᵢ³}