forgejo/modules/markup/markdown/math/inline_renderer.go
zeripath 88c2e24360
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>
2022-09-14 00:33:37 +08:00

47 lines
1.3 KiB
Go

// Copyright 2022 The Gitea Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.
package math
import (
"bytes"
"github.com/yuin/goldmark/ast"
"github.com/yuin/goldmark/renderer"
"github.com/yuin/goldmark/util"
)
// InlineRenderer is an inline renderer
type InlineRenderer struct{}
// NewInlineRenderer returns a new renderer for inline math
func NewInlineRenderer() renderer.NodeRenderer {
return &InlineRenderer{}
}
func (r *InlineRenderer) renderInline(w util.BufWriter, source []byte, n ast.Node, entering bool) (ast.WalkStatus, error) {
if entering {
_, _ = w.WriteString(`<code class="language-math is-loading">`)
for c := n.FirstChild(); c != nil; c = c.NextSibling() {
segment := c.(*ast.Text).Segment
value := util.EscapeHTML(segment.Value(source))
if bytes.HasSuffix(value, []byte("\n")) {
_, _ = w.Write(value[:len(value)-1])
if c != n.LastChild() {
_, _ = w.Write([]byte(" "))
}
} else {
_, _ = w.Write(value)
}
}
return ast.WalkSkipChildren, nil
}
_, _ = w.WriteString(`</code>`)
return ast.WalkContinue, nil
}
// RegisterFuncs registers the renderer for inline math nodes
func (r *InlineRenderer) RegisterFuncs(reg renderer.NodeRendererFuncRegisterer) {
reg.Register(KindInline, r.renderInline)
}