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joplin/packages/renderer/MdToHtml/rules/katex.ts

358 lines
11 KiB
TypeScript

import { RuleOptions } from '../../MdToHtml';
let katex = require('katex');
const md5 = require('md5');
const mhchemModule = require('./katex_mhchem.js');
// Katex macros include circular references so we need
// to serialize them with json-stringify-safe
const stringifySafe = require('json-stringify-safe');
function stringifyKatexOptions(options: any) {
if (!options) return '';
const newOptions = { ...options };
// The Katex macro structure is extremely verbose and slow to cache,
// so we need bespoke code to serialize it.
// macros:
// \hb: {tokens: Array(1), numArgs: 0}
// \d: {tokens: Array(7), numArgs: 1}
// \e:
// tokens: Array(11)
// 0: Token {text: "}", loc: SourceLocation, noexpand: undefined, treatAsRelax: undefined}
// 1: Token {text: "1", loc: SourceLocation, noexpand: undefined, treatAsRelax: undefined}
// 2: Token {text: "#", loc: SourceLocation, noexpand: undefined, treatAsRelax: undefined}
// 3: Token {text: "{", loc: SourceLocation, noexpand: undefined, treatAsRelax: undefined}
// 4: Token {text: "^", loc: SourceLocation, noexpand: undefined, treatAsRelax: undefined}
// 5: Token {text: "}", loc: SourceLocation, noexpand: undefined, treatAsRelax: undefined}
// 6: Token {text: "e", loc: SourceLocation, noexpand: undefined, treatAsRelax: undefined}
// 7: Token {text: " ", loc: SourceLocation, noexpand: undefined, treatAsRelax: undefined}
// 8: Token {text: "m", loc: SourceLocation, noexpand: undefined, treatAsRelax: undefined}
// 9: Token {text: " ", loc: SourceLocation, noexpand: undefined, treatAsRelax: undefined}
// 10: Token {text: "{", loc: SourceLocation, noexpand: undefined, treatAsRelax: undefined}
// numArgs: 1
// \dv: {tokens: Array(15), numArgs: 2}
// \ddv: {tokens: Array(19), numArgs: 2}
// \pdv: {tokens: Array(15), numArgs: 2}
// \pddv: {tokens: Array(15), numArgs: 2}
// \abs: {tokens: Array(10), numArgs: 1}
// \inflim: {tokens: Array(10), numArgs: 0}
// \infint: {tokens: Array(2), numArgs: 0}
// \prob: {tokens: Array(12), numArgs: 1}
// \expval: {tokens: Array(14), numArgs: 2}
// \wf: {tokens: Array(6), numArgs: 0}
// \@eqnsw: "1"
//
// Additionally, some KaTeX macros don't follow this general format. For example
// \@eqnsw: "1"
// is created by \begin{align}...\end{align} environments, and doesn't have a "tokens" property.
if (options.macros) {
const toSerialize: any = {};
for (const k of Object.keys(options.macros)) {
const macro = options.macros[k];
if (typeof macro === 'string') {
toSerialize[k] = `${macro}_string`;
} else {
const macroText: string[] = macro.tokens.map((t: any) => t.text);
toSerialize[k] = `${macroText.join('')}_${macro.numArgs}`;
}
}
newOptions.macros = toSerialize;
}
return stringifySafe(newOptions);
}
katex = mhchemModule(katex);
function katexStyle() {
return [
{ name: 'katex.css' },
// Note: Declaring the fonts is not needed for in-app rendering because
// they will be loaded automatically from katex.css.
// However they must be specified for exporting notes to HTML and PDF,
// so that they can be bundled with the other assets.
{ name: 'fonts/KaTeX_AMS-Regular.woff2' },
{ name: 'fonts/KaTeX_Caligraphic-Bold.woff2' },
{ name: 'fonts/KaTeX_Caligraphic-Regular.woff2' },
{ name: 'fonts/KaTeX_Fraktur-Bold.woff2' },
{ name: 'fonts/KaTeX_Fraktur-Regular.woff2' },
{ name: 'fonts/KaTeX_Main-Bold.woff2' },
{ name: 'fonts/KaTeX_Main-BoldItalic.woff2' },
{ name: 'fonts/KaTeX_Main-Italic.woff2' },
{ name: 'fonts/KaTeX_Main-Regular.woff2' },
{ name: 'fonts/KaTeX_Math-BoldItalic.woff2' },
{ name: 'fonts/KaTeX_Math-Italic.woff2' },
{ name: 'fonts/KaTeX_SansSerif-Bold.woff2' },
{ name: 'fonts/KaTeX_SansSerif-Italic.woff2' },
{ name: 'fonts/KaTeX_SansSerif-Regular.woff2' },
{ name: 'fonts/KaTeX_Script-Regular.woff2' },
{ name: 'fonts/KaTeX_Size1-Regular.woff2' },
{ name: 'fonts/KaTeX_Size2-Regular.woff2' },
{ name: 'fonts/KaTeX_Size3-Regular.woff2' },
{ name: 'fonts/KaTeX_Size4-Regular.woff2' },
{ name: 'fonts/KaTeX_Typewriter-Regular.woff2' },
];
}
// Test if potential opening or closing delimieter
// Assumes that there is a "$" at state.src[pos]
function isValidDelim(state: any, pos: number) {
const max = state.posMax;
let can_open = true,
can_close = true;
const prevChar = pos > 0 ? state.src.charCodeAt(pos - 1) : -1;
const nextChar = pos + 1 <= max ? state.src.charCodeAt(pos + 1) : -1;
// Check non-whitespace conditions for opening and closing, and
// check that closing delimeter isn't followed by a number
if (prevChar === 0x20 /* " " */ || prevChar === 0x09 /* \t */ || (nextChar >= 0x30 /* "0" */ && nextChar <= 0x39) /* "9" */) {
can_close = false;
}
if (nextChar === 0x20 /* " " */ || nextChar === 0x09 /* \t */) {
can_open = false;
}
return {
can_open: can_open,
can_close: can_close,
};
}
function math_inline(state: any, silent: boolean) {
let match, token, res, pos;
if (state.src[state.pos] !== '$') {
return false;
}
res = isValidDelim(state, state.pos);
if (!res.can_open) {
if (!silent) {
state.pending += '$';
}
state.pos += 1;
return true;
}
// First check for and bypass all properly escaped delimieters
// This loop will assume that the first leading backtick can not
// be the first character in state.src, which is known since
// we have found an opening delimieter already.
const start = state.pos + 1;
match = start;
while ((match = state.src.indexOf('$', match)) !== -1) {
// Found potential $, look for escapes, pos will point to
// first non escape when complete
pos = match - 1;
while (state.src[pos] === '\\') {
pos -= 1;
}
// Even number of escapes, potential closing delimiter found
if ((match - pos) % 2 === 1) {
break;
}
match += 1;
}
// No closing delimter found. Consume $ and continue.
if (match === -1) {
if (!silent) {
state.pending += '$';
}
state.pos = start;
return true;
}
// Check if we have empty content, ie: $$. Do not parse.
if (match - start === 0) {
if (!silent) {
state.pending += '$$';
}
state.pos = start + 1;
return true;
}
// Check for valid closing delimiter
res = isValidDelim(state, match);
if (!res.can_close) {
if (!silent) {
state.pending += '$';
}
state.pos = start;
return true;
}
if (!silent) {
token = state.push('math_inline', 'math', 0);
token.markup = '$';
token.content = state.src.slice(start, match);
}
state.pos = match + 1;
return true;
}
function math_block(state: any, start: number, end: number, silent: boolean) {
let firstLine,
lastLine,
next,
lastPos,
found = false,
pos = state.bMarks[start] + state.tShift[start],
max = state.eMarks[start];
if (pos + 2 > max) {
return false;
}
if (state.src.slice(pos, pos + 2) !== '$$') {
return false;
}
pos += 2;
firstLine = state.src.slice(pos, max);
if (silent) {
return true;
}
if (firstLine.trim().slice(-2) === '$$') {
// Single line expression
firstLine = firstLine.trim().slice(0, -2);
found = true;
}
for (next = start; !found;) {
next++;
if (next >= end) {
break;
}
pos = state.bMarks[next] + state.tShift[next];
max = state.eMarks[next];
if (pos < max && state.tShift[next] < state.blkIndent) {
// non-empty line with negative indent should stop the list:
break;
}
if (
state.src
.slice(pos, max)
.trim()
.slice(-2) === '$$'
) {
lastPos = state.src.slice(0, max).lastIndexOf('$$');
lastLine = state.src.slice(pos, lastPos);
found = true;
}
}
state.line = next + 1;
const contentLines = [];
if (firstLine && firstLine.trim()) {
contentLines.push(firstLine);
}
const includeTrailingNewline = false;
const interiorLines = state.getLines(start + 1, next, state.tShift[start], includeTrailingNewline);
if (interiorLines.length > 0) {
contentLines.push(interiorLines);
}
if (lastLine && lastLine.trim()) {
contentLines.push(lastLine);
}
const token = state.push('math_block', 'math', 0);
token.block = true;
token.content = contentLines.join('\n');
token.map = [start, state.line];
token.markup = '$$';
return true;
}
const cache_: any = {};
function renderToStringWithCache(latex: string, katexOptions: any) {
const cacheKey = md5(escape(latex) + escape(stringifyKatexOptions(katexOptions)));
if (cacheKey in cache_) {
return cache_[cacheKey];
} else {
const beforeMacros = stringifyKatexOptions(katexOptions.macros);
const output = katex.renderToString(latex, katexOptions);
const afterMacros = stringifyKatexOptions(katexOptions.macros);
// Don't cache the formulas that add macros, otherwise
// they won't be added on second run.
if (beforeMacros === afterMacros) cache_[cacheKey] = output;
return output;
}
}
function renderKatexError(latex: string, error: any): string {
console.error('Katex error for:', latex, error);
return `<div class="inline-code">${error.message}</div>`;
}
export default {
plugin: function(markdownIt: any, options: RuleOptions) {
// Keep macros that persist across Katex blocks to allow defining a macro
// in one block and re-using it later in other blocks.
// https://github.com/laurent22/joplin/issues/1105
if (!options.context.userData.__katex) options.context.userData.__katex = { macros: {} };
const katexOptions: any = {};
katexOptions.macros = options.context.userData.__katex.macros;
katexOptions.trust = true;
// set KaTeX as the renderer for markdown-it-simplemath
const katexInline = function(latex: string) {
katexOptions.displayMode = false;
let outputHtml = '';
try {
outputHtml = renderToStringWithCache(latex, katexOptions);
} catch (error) {
outputHtml = renderKatexError(latex, error);
}
return `<span class="joplin-editable"><span class="joplin-source" data-joplin-language="katex" data-joplin-source-open="$" data-joplin-source-close="$">${markdownIt.utils.escapeHtml(latex)}</span>${outputHtml}</span>`;
};
const inlineRenderer = function(tokens: any[], idx: number) {
return katexInline(tokens[idx].content);
};
const katexBlock = function(latex: string) {
katexOptions.displayMode = true;
let outputHtml = '';
try {
outputHtml = renderToStringWithCache(latex, katexOptions);
} catch (error) {
outputHtml = renderKatexError(latex, error);
}
return `<div class="joplin-editable"><pre class="joplin-source" data-joplin-language="katex" data-joplin-source-open="$$&#10;" data-joplin-source-close="&#10;$$&#10;">${markdownIt.utils.escapeHtml(latex)}</pre>${outputHtml}</div>`;
};
const blockRenderer = function(tokens: any[], idx: number) {
return `${katexBlock(tokens[idx].content)}\n`;
};
markdownIt.inline.ruler.after('escape', 'math_inline', math_inline);
markdownIt.block.ruler.after('blockquote', 'math_block', math_block, {
alt: ['paragraph', 'reference', 'blockquote', 'list'],
});
markdownIt.renderer.rules.math_inline = inlineRenderer;
markdownIt.renderer.rules.math_block = blockRenderer;
},
assets: katexStyle,
};