fix(epub): embed fonts in the Rust packager instead of fetching in the webview

src-tauri/src/epub.rs

@@ -5,6 +5,9 @@ use std::io::Write;
 use zip::write::SimpleFileOptions;
 use zip::{CompressionMethod, ZipWriter};
 
+static LITERATA: &[u8] = include_bytes!("../../public/fonts/Literata-VF.ttf");
+static LITERATA_ITALIC: &[u8] = include_bytes!("../../public/fonts/Literata-Italic-VF.ttf");
+
 #[derive(Deserialize)]
 pub struct EpubFile {
     path: String,
@@ -17,10 +20,8 @@ fn build(files: &[EpubFile]) -> Result<Vec<u8>, String> {
     let mut zip = ZipWriter::new(buffer);
 
     let stored = SimpleFileOptions::default().compression_method(CompressionMethod::Stored);
-    zip.start_file("mimetype", stored)
+    zip.start_file("mimetype", stored).map_err(|e| e.to_string())?;
-        .map_err(|e| e.to_string())?;
+    zip.write_all(b"application/epub+zip").map_err(|e| e.to_string())?;
-    zip.write_all(b"application/epub+zip")
-        .map_err(|e| e.to_string())?;
 
     let deflated = SimpleFileOptions::default().compression_method(CompressionMethod::Deflated);
     for file in files {
@@ -33,11 +34,18 @@ fn build(files: &[EpubFile]) -> Result<Vec<u8>, String> {
                 .map_err(|e| format!("failed to decode \"{}\": {e}", file.path))?,
             _ => file.data.as_bytes().to_vec(),
         };
-        zip.start_file(&file.path, deflated)
+        zip.start_file(&file.path, deflated).map_err(|e| e.to_string())?;
-            .map_err(|e| e.to_string())?;
         zip.write_all(&bytes).map_err(|e| e.to_string())?;
     }
 
+    for (path, bytes) in [
+        ("OEBPS/fonts/Literata-VF.ttf", LITERATA),
+        ("OEBPS/fonts/Literata-Italic-VF.ttf", LITERATA_ITALIC),
+    ] {
+        zip.start_file(path, deflated).map_err(|e| e.to_string())?;
+        zip.write_all(bytes).map_err(|e| e.to_string())?;
+    }
+
     Ok(zip.finish().map_err(|e| e.to_string())?.into_inner())
 }
 

src/export/epub.ts

@@ -389,24 +389,8 @@ export function bookToEpub(book: Book): EpubFile[] {
   return files;
 }
 
-function toBase64(bytes: Uint8Array): string {
-  let binary = "";
-  for (let i = 0; i < bytes.length; i++) binary += String.fromCharCode(bytes[i]);
-  return btoa(binary);
-}
-
-async function fontFile(url: string, path: string): Promise<EpubFile> {
-  const response = await fetch(url);
-  const buffer = await response.arrayBuffer();
-  return { path, data: toBase64(new Uint8Array(buffer)), encoding: "base64" };
-}
-
 export async function buildEpub(book: Book): Promise<Uint8Array> {
   const files = bookToEpub(book);
-  files.push(
-    await fontFile("/fonts/Literata-VF.ttf", "OEBPS/fonts/Literata-VF.ttf"),
-    await fontFile("/fonts/Literata-Italic-VF.ttf", "OEBPS/fonts/Literata-Italic-VF.ttf"),
-  );
   const buf = await invoke<ArrayBuffer>("package_epub", { files });
   return new Uint8Array(buf);
 }