From d5830170808353f64038c0b3cb3c931c39c74d9c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan=20Christian=20Gr=C3=BCnhage?=
 <jan.christian@gruenhage.xyz>
Date: Mon, 31 Aug 2020 21:33:36 +0200
Subject: [PATCH] feat: add katex support

---
 README.md                       | 28 ++++++++++++++++++++++++++++
 templates/index.html            | 15 +++++++++++++++
 templates/shortcodes/katex.html |  1 +
 3 files changed, 44 insertions(+)
 create mode 100644 templates/shortcodes/katex.html

diff --git a/README.md b/README.md
index 0c43d93..183dd6b 100644
--- a/README.md
+++ b/README.md
@@ -83,5 +83,33 @@ date = 1970-01-01
 author = "John Smith"
 ```
 
+### KaTeX math formula support
+
+This theme contains math formula support using [KaTeX](https://katex.org/),
+which can be enabled by setting `katex_enable = true` in the `extra` section
+of `config.toml`:
+
+```toml
+[extra]
+katex_enable = true
+```
+
+After enabling this extension, the `katex` short code can be used in documents:
+* `{{ katex(body="\KaTeX") }}` to typeset a math formula inlined into a text,
+  similar to `$...$` in LaTeX
+* `{% katex(block=true) %}\KaTeX{% end %}` to typeset a block of math formulas,
+  similar to `$$...$$` in LaTeX
+
+#### Automatic rendering without short codes
+
+Optionally, `\\( \KaTeX \\)` inline and `\\[ \KaTeX \\]` / `$$ \KaTeX $$`
+block-style automatic rendering is also supported, if enabled in the config:
+
+```toml
+[extra]
+katex_enable = true
+katex_auto_render = true
+```
+
 ## Original
 This template is based on the Hugo template https://git.habd.as/comfusion/after-dark
diff --git a/templates/index.html b/templates/index.html
index 7d16008..ce78415 100644
--- a/templates/index.html
+++ b/templates/index.html
@@ -17,8 +17,23 @@
 
       {% block css %}
           <link rel="stylesheet" href="{{ get_url(path="site.css", trailing_slash=false) | safe }}">
+		  {% if config.extra.katex_enable %}
+          <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/katex@0.10.0/dist/katex.min.css" integrity="sha384-9eLZqc9ds8eNjO3TmqPeYcDj8n+Qfa4nuSiGYa6DjLNcv9BtN69ZIulL9+8CqC9Y" crossorigin="anonymous">
+          {% endif %}
       {% endblock css %}
 
+      {% block js %}
+          {% if config.extra.katex_enable %}
+          <script defer src="https://cdn.jsdelivr.net/npm/katex@0.10.0/dist/katex.min.js" integrity="sha384-K3vbOmF2BtaVai+Qk37uypf7VrgBubhQreNQe9aGsz9lB63dIFiQVlJbr92dw2Lx" crossorigin="anonymous"></script>
+          <script defer src="https://cdn.jsdelivr.net/npm/katex@0.10.0/dist/contrib/mathtex-script-type.min.js" integrity="sha384-zWYbd0NBwgTsgIdFKVprSfTh1mbMPe5Hz1X3yY4Sd1h/K1cQoUe36OGwAGz/PcDy" crossorigin="anonymous"></script>
+              {% if config.extra.katex_auto_render %}
+          <script defer src="https://cdn.jsdelivr.net/npm/katex@0.10.0/dist/contrib/auto-render.min.js" integrity="sha384-kmZOZB5ObwgQnS/DuDg6TScgOiWWBiVt0plIRkZCmE6rDZGrEOQeHM5PcHi+nyqe" crossorigin="anonymous"
+                  onload="renderMathInElement(document.body);"></script>
+              {% endif %}
+          {% endif %}
+
+      {% endblock js %}
+
       {% block extra_head %}
       {% endblock extra_head %}
     </head>
diff --git a/templates/shortcodes/katex.html b/templates/shortcodes/katex.html
new file mode 100644
index 0000000..1d13c0a
--- /dev/null
+++ b/templates/shortcodes/katex.html
@@ -0,0 +1 @@
+ <script type="math/tex{% if block %};mode=display{% endif %}">{{body}}</script>