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joplin/ReactNativeClient/lib/MdToHtml_Katex.js

67 lines
2.2 KiB
JavaScript

const { shim } = require('lib/shim');
const katex = require('katex');
const katexCss = require('lib/csstojs/katex.css.js');
const Setting = require('lib/models/Setting');
class MdToHtml_Katex {
constructor() {
this.cache_ = {};
this.assetsLoaded_ = false;
}
name() {
return 'katex';
}
processContent(renderedTokens, content, tagType) {
try {
const cacheKey = tagType + '_' + content;
let renderered = null;
if (this.cache_[cacheKey]) {
renderered = this.cache_[cacheKey];
} else {
renderered = katex.renderToString(content, {
displayMode: tagType === 'block',
});
this.cache_[cacheKey] = renderered;
}
if (tagType === 'block') renderered = '<p>' + renderered + '</p>';
renderedTokens.push(renderered);
} catch (error) {
renderedTokens.push('Cannot render Katex content: ' + error.message);
}
return renderedTokens;
}
extraCss() {
return katexCss;
}
async loadAssets() {
if (this.assetsLoaded_) return;
// In node, the fonts are simply copied using copycss to where Katex expects to find them, which is under app/gui/note-viewer/fonts
// In React Native, it's more complicated and we need to download and copy them to the right directory. Ideally, we should embed
// them as an asset and copy them from there (or load them from there by modifying Katex CSS), but for now that will do.
if (shim.isReactNative()) {
// Fonts must go under the resourceDir directory because this is the baseUrl of NoteBodyViewer
const baseDir = Setting.value('resourceDir');
await shim.fsDriver().mkdir(baseDir + '/fonts');
await shim.fetchBlob('https://cdnjs.cloudflare.com/ajax/libs/KaTeX/0.9.0-beta1/fonts/KaTeX_Main-Regular.woff2', { overwrite: false, path: baseDir + '/fonts/KaTeX_Main-Regular.woff2' });
await shim.fetchBlob('https://cdnjs.cloudflare.com/ajax/libs/KaTeX/0.9.0-beta1/fonts/KaTeX_Math-Italic.woff2', { overwrite: false, path: baseDir + '/fonts/KaTeX_Math-Italic.woff2' });
await shim.fetchBlob('https://cdnjs.cloudflare.com/ajax/libs/KaTeX/0.9.0-beta1/fonts/KaTeX_Size1-Regular.woff2', { overwrite: false, path: baseDir + '/fonts/KaTeX_Size1-Regular.woff2' });
}
this.assetsLoaded_ = true;
}
}
module.exports = MdToHtml_Katex;