fix latex rendering

examples/server/webui/package-lock.json

@@ -12,6 +12,7 @@
         "autoprefixer": "^10.4.20",
         "daisyui": "^4.12.14",
         "highlight.js": "^11.10.0",
+        "katex": "^0.16.15",
         "markdown-it": "^14.1.0",
         "postcss": "^8.4.49",
         "tailwindcss": "^3.4.15",

examples/server/webui/package.json

@@ -18,6 +18,7 @@
     "autoprefixer": "^10.4.20",
     "daisyui": "^4.12.14",
     "highlight.js": "^11.10.0",
+    "katex": "^0.16.15",
     "markdown-it": "^14.1.0",
     "postcss": "^8.4.49",
     "tailwindcss": "^3.4.15",

examples/server/webui/public/demo-conversation.json

@@ -11,7 +11,7 @@
     {
       "id": 1734087548327,
       "role": "assistant",
-      "content": "This is the formula:\n$\\frac{e^{x_i}}{\\sum_{j=1}^{n}e^{x_j}}$\n\nGiven an input vector \\(\\mathbf{x} = [x_1, x_2, \\ldots, x_n]\\)\n\n\\[\ny_i = \\frac{e^{x_i}}{\\sum_{j=1}^n e^{x_j}}\n\\]\n\nCode block latex:\n```latex\n\\frac{e^{x_i}}{\\sum_{j=1}^{n}e^{x_j}}\n```",
+      "content": "This is the formula:\n$\\frac{e^{x_i}}{\\sum_{j=1}^{n}e^{x_j}}$\n\nGiven an input vector \\(\\mathbf{x} = [x_1, x_2, \\ldots, x_n]\\)\n\n\\[\ny_i = \\frac{e^{x_i}}{\\sum_{j=1}^n e^{x_j}}\n\\]\n\nCode block latex:\n```latex\n\\frac{e^{x_i}}{\\sum_{j=1}^{n}e^{x_j}}\n```\n\nTest dollar sign: $1234 $4567\n\nInvalid latex syntax: $E = mc^$ and $$E = mc^$$",
       "timings": {
         "prompt_n": 1,
         "prompt_ms": 28.923,

examples/server/webui/src/katex-gpt.js

@@ -0,0 +1,66 @@
+import katex from 'katex';
+
+// Adapted from https://github.com/SchneeHertz/markdown-it-katex-gpt
+// MIT license
+
+const defaultOptions = {
+  delimiters: [
+    { left: '\\[', right: '\\]', display: true },
+    { left: '\\(', right: '\\)', display: false },
+  ],
+};
+
+export function renderLatexHTML(content, display = false) {
+  return katex.renderToString(content, {
+    throwOnError: false,
+    output: 'mathml',
+    displayMode: display,
+  });
+}
+
+function escapedBracketRule(options) {
+  return (state, silent) => {
+    const max = state.posMax;
+    const start = state.pos;
+
+    for (const { left, right, display } of options.delimiters) {
+
+      // Check if it starts with the left delimiter
+      if (!state.src.slice(start).startsWith(left)) continue;
+
+      // Skip the length of the left delimiter
+      let pos = start + left.length;
+
+      // Find the matching right delimiter
+      while (pos < max) {
+        if (state.src.slice(pos).startsWith(right)) {
+          break;
+        }
+        pos++;
+      }
+
+      // No matching right delimiter found, skip to the next match
+      if (pos >= max) continue;
+
+      // If not in silent mode, convert LaTeX formula to MathML
+      if (!silent) {
+        const content = state.src.slice(start + left.length, pos);
+        try {
+          const renderedContent = renderLatexHTML(content, display);
+          const token = state.push('html_inline', '', 0);
+          token.content = renderedContent;
+        } catch (e) {
+          console.error(e);
+        }
+      }
+
+      // Update position, skip the length of the right delimiter
+      state.pos = pos + right.length;
+      return true;
+    }
+  }
+}
+
+export default function (md, options = defaultOptions) {
+  md.inline.ruler.after('text', 'escaped_bracket', escapedBracketRule(options));
+}

examples/server/webui/src/main.js

@@ -5,7 +5,8 @@ import TextLineStream from 'textlinestream';
 
 // math formula rendering
 import 'katex/dist/katex.min.css';
-import markdownItKatex from '@vscode/markdown-it-katex';
+import markdownItKatexGpt, { renderLatexHTML } from './katex-gpt';
+import markdownItKatexNormal from '@vscode/markdown-it-katex';
 
 // code highlighting
 import hljs from './highlight-config';
@@ -90,6 +91,9 @@ const VueMarkdown = defineComponent(
     const md = shallowRef(new MarkdownIt({
       breaks: true,
       highlight: function (str, lang) { // Add highlight.js
+        if (lang === 'latex') {
+          return renderLatexHTML(str, true);
+        }
         if (lang && hljs.getLanguage(lang)) {
           try {
             return '<pre><code class="hljs">' +
@@ -100,7 +104,8 @@ const VueMarkdown = defineComponent(
         return '<pre><code class="hljs">' + md.value.utils.escapeHtml(str) + '</code></pre>';
       }
     }));
-    md.value.use(markdownItKatex, {
+    // support latex with double dollar sign and square brackets
+    md.value.use(markdownItKatexGpt, {
       delimiters: [
         { left: '\\[', right: '\\]', display: true },
         { left: '\\(', right: '\\)', display: false },
@@ -108,6 +113,9 @@ const VueMarkdown = defineComponent(
       ],
       throwOnError: false,
     });
+    // support latex with single dollar sign
+    md.value.use(markdownItKatexNormal, { throwOnError: false });
+    // add copy button to code blocks
     const origFenchRenderer = md.value.renderer.rules.fence;
     md.value.renderer.rules.fence = (tokens, idx, ...args) => {
       const content = tokens[idx].content;