feat(export): PDF and EPUB export with save dialog

src/export/exporters.ts

@@ -0,0 +1,19 @@
+import type { Book } from "../model/book";
+import { bookToPdfInputs } from "./typst";
+import { buildEpub } from "./epub";
+import { compilePdf } from "../ipc";
+import { saveBytes } from "../project";
+
+const PDF = [{ name: "PDF", extensions: ["pdf"] }];
+const EPUB = [{ name: "EPUB", extensions: ["epub"] }];
+
+export async function exportPdf(book: Book): Promise<void> {
+  const { source, images } = bookToPdfInputs(book);
+  const bytes = await compilePdf(source, images);
+  await saveBytes(bytes, `${book.metadata.title || "Untitled"}.pdf`, PDF);
+}
+
+export async function exportEpub(book: Book): Promise<void> {
+  const bytes = await buildEpub(book);
+  await saveBytes(bytes, `${book.metadata.title || "Untitled"}.epub`, EPUB);
+}

src/project.ts

@@ -18,3 +18,22 @@ export async function openBook(): Promise<{ book: Book; path: string } | null> {
   const contents = await invoke<string>("read_file", { path: selected });
   return { book: JSON.parse(contents) as Book, path: selected };
 }
+
+function toBase64(bytes: Uint8Array): string {
+  let binary = "";
+  const chunk = 0x8000;
+  for (let i = 0; i < bytes.length; i += chunk) {
+    binary += String.fromCharCode(...bytes.subarray(i, i + chunk));
+  }
+  return btoa(binary);
+}
+
+export async function saveBytes(
+  bytes: Uint8Array,
+  defaultName: string,
+  filters: { name: string; extensions: string[] }[]
+): Promise<void> {
+  const path = await save({ filters, defaultPath: defaultName });
+  if (!path) return;
+  await invoke("write_bytes", { path, data: toBase64(bytes) });
+}