feat(monospace): build CSS with embedded woff2 base64

src/main/ExportCss.js

@@ -0,0 +1,25 @@
+'use strict';
+
+const { FAMILY_BY_KEY } = require('./settings/monospaceSettings');
+
+function buildFontFaceBlock(family, woff2Bytes) {
+  const safeFamily = family.replace(/'/g, "\\'");
+  const b64 = Buffer.from(woff2Bytes).toString('base64');
+  return `@font-face {
+  font-family: '${safeFamily}';
+  src: url(data:font/woff2;base64,${b64}) format('woff2');
+  font-weight: 100 900;
+  font-style: normal;
+  font-display: swap;
+}`;
+}
+
+function buildExportCss(settings, { woff2 } = {}) {
+  const family = (settings && FAMILY_BY_KEY[settings.monospaceFont]) || 'JetBrains Mono';
+  const ligatures = !!(settings && settings.monospaceLigatures === true);
+  const face = buildFontFaceBlock(family, woff2 || Buffer.alloc(0));
+  const feature = ligatures ? `code, pre, kbd, samp { font-feature-settings: 'liga' 1, 'calt' 1; }` : '';
+  return [face, feature].filter(Boolean).join('\n\n');
+}
+
+module.exports = { buildExportCss, buildFontFaceBlock };

tests/unit/main/monospace/ExportCss.test.js

@@ -0,0 +1,36 @@
+const { buildExportCss, buildFontFaceBlock } = require('../../../../src/main/ExportCss');
+
+describe('ExportCss', () => {
+  test('buildFontFaceBlock emits @font-face with base64 data URI', () => {
+    const woff2 = Buffer.from([0x77, 0x4f, 0x46, 0x32]);
+    const css = buildFontFaceBlock('JetBrains Mono', woff2);
+    expect(css).toContain('@font-face');
+    expect(css).toContain("font-family: 'JetBrains Mono'");
+    expect(css).toContain("format('woff2')");
+    expect(css).toContain('base64,');
+    const m = css.match(/base64,([A-Za-z0-9+/=]+)/);
+    expect(m).toBeTruthy();
+    expect(Buffer.from(m[1], 'base64')).toEqual(woff2);
+  });
+
+  test('buildExportCss writes @font-face + ligatures when enabled', () => {
+    const woff2 = Buffer.from([0x77, 0x4f, 0x46, 0x32]);
+    const css = buildExportCss(
+      { monospaceFont: 'jetbrains-mono', monospaceLigatures: true },
+      { woff2 }
+    );
+    expect(css).toContain('@font-face');
+    expect(css).toContain('font-feature-settings');
+    expect(css).toContain("'liga' 1");
+  });
+
+  test('buildExportCss with ligatures off omits font-feature-settings', () => {
+    const woff2 = Buffer.from([0x77, 0x4f, 0x46, 0x32]);
+    const css = buildExportCss(
+      { monospaceFont: 'fira-code', monospaceLigatures: false },
+      { woff2 }
+    );
+    expect(css).not.toContain('font-feature-settings');
+    expect(css).toContain('Fira Code');
+  });
+});