Add KaTeX rendering to Markdown. (#20571)

This PR adds mathematical rendering with KaTeX.

The first step is to add a Goldmark extension that detects the latex
(and tex) mathematics delimiters.

The second step to make this extension only run if math support is
enabled.

The second step is to then add KaTeX CSS and JS to the head which will
load after the dom is rendered.

Fix #3445

Signed-off-by: Andrew Thornton <art27@cantab.net>

Signed-off-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
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zeripath 2022-09-13 17:33:37 +01:00 committed by GitHub
parent eaa561145a
commit 88c2e24360
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28 changed files with 1079 additions and 174 deletions

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@ -236,6 +236,7 @@ The following configuration set `Content-Type: application/vnd.android.package-a
- `CUSTOM_URL_SCHEMES`: Use a comma separated list (ftp,git,svn) to indicate additional
URL hyperlinks to be rendered in Markdown. URLs beginning in http and https are
always displayed
- `ENABLE_MATH`: **true**: Enables detection of `\(...\)`, `\[...\]`, `$...$` and `$$...$$` blocks as math blocks.
## Server (`server`)

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@ -74,12 +74,13 @@ RENDER_COMMAND = "timeout 30s pandoc +RTS -M512M -RTS -f rst"
IS_INPUT_FILE = false
```
If your external markup relies on additional classes and attributes on the generated HTML elements, you might need to enable custom sanitizer policies. Gitea uses the [`bluemonday`](https://godoc.org/github.com/microcosm-cc/bluemonday) package as our HTML sanitizier. The example below will support [KaTeX](https://katex.org/) output from [`pandoc`](https://pandoc.org/).
If your external markup relies on additional classes and attributes on the generated HTML elements, you might need to enable custom sanitizer policies. Gitea uses the [`bluemonday`](https://godoc.org/github.com/microcosm-cc/bluemonday) package as our HTML sanitizer. The example below could be used to support server-side [KaTeX](https://katex.org/) rendering output from [`pandoc`](https://pandoc.org/).
```ini
[markup.sanitizer.TeX]
; Pandoc renders TeX segments as <span>s with the "math" class, optionally
; with "inline" or "display" classes depending on context.
; - note this is different from the built-in math support in our markdown parser which uses <code>
ELEMENT = span
ALLOW_ATTR = class
REGEXP = ^\s*((math(\s+|$)|inline(\s+|$)|display(\s+|$)))+