fix(producer): skip slow TTC recompression

packages/producer/src/services/deterministicFonts-systemCapture.test.ts

@@ -12,7 +12,7 @@
 
 import { describe, expect, it } from "bun:test";
 import { existsSync } from "node:fs";
-import { injectDeterministicFontFaces } from "./deterministicFonts.js";
+import { fontFormatHint, injectDeterministicFontFaces } from "./deterministicFonts.js";
 
 // A font family that is NOT in FONT_ALIASES but exists on macOS as
 // /System/Library/Fonts/Supplemental/Impact.ttf. When Google Fonts
@@ -36,6 +36,11 @@ function makeHttp400Fetch(): typeof fetch {
 }
 
 describe("system font capture — allowSystemFontCapture option", () => {
+  it("uses the CSS collection hint for raw TTC data URIs", () => {
+    expect(fontFormatHint("data:font/collection;base64,AA==")).toBe("collection");
+    expect(fontFormatHint("data:font/woff2;base64,AA==")).toBe("woff2");
+  });
+
   it("does not attempt system font capture when allowSystemFontCapture is false", async () => {
     const html = makeHtml("NotARealFontFamilyForTest");
     const result = await injectDeterministicFontFaces(html, {

packages/producer/src/services/deterministicFonts.ts

@@ -432,6 +432,10 @@ function extractRequestedFontFamilies(html: string): Map<string, string> {
   return requested;
 }
 
+export function fontFormatHint(src: string): "collection" | "woff2" {
+  return src.startsWith("data:font/collection;") ? "collection" : "woff2";
+}
+
 function buildFontFaceRule(
   familyName: string,
   src: string,
@@ -442,7 +446,7 @@ function buildFontFaceRule(
   return [
     "@font-face {",
     `  font-family: "${familyName}";`,
-    `  src: url("${src}") format("woff2");`,
+    `  src: url("${src}") format("${fontFormatHint(src)}");`,
     `  font-style: ${style};`,
     `  font-weight: ${weight};`,
     "  font-display: block;",

packages/producer/src/services/fontCompression.test.ts

@@ -72,9 +72,17 @@ describe("fontToDataUri", () => {
     expect(uri).toMatch(/^data:font\/otf;base64,/);
   });
 
-  it("falls back with correct MIME type for ttc", async () => {
-    const garbage = Buffer.from("not a font");
-    const uri = await fontToDataUri(garbage, "ttc");
-    expect(uri).toMatch(/^data:font\/collection;base64,/);
+  it("embeds ttc collections raw without attempting slow woff2 compression", async () => {
+    const warnings: unknown[][] = [];
+    const originalWarn = console.warn;
+    console.warn = (...args: unknown[]) => warnings.push(args);
+    try {
+      const raw = Buffer.from("ttc-bytes");
+      const uri = await fontToDataUri(raw, "ttc");
+      expect(uri).toBe(`data:font/collection;base64,${raw.toString("base64")}`);
+      expect(warnings).toHaveLength(0);
+    } finally {
+      console.warn = originalWarn;
+    }
   });
 });

packages/producer/src/services/fontCompression.ts

@@ -22,6 +22,9 @@ export async function fontToDataUri(input: Buffer, originalFormat: string): Prom
   if (originalFormat === "woff2") {
     return `data:font/woff2;base64,${input.toString("base64")}`;
   }
+  if (originalFormat === "ttc") {
+    return `data:font/collection;base64,${input.toString("base64")}`;
+  }
   try {
     const compressed = await compressToWoff2(input);
     return `data:font/woff2;base64,${compressed.toString("base64")}`;