Add Script class wrapping hb_script_t

Author: khaledhosny

MIGRATING.md

@@ -70,6 +70,7 @@ Affected APIs:
 - `Buffer.serialize` now takes a single options object: `{ font, start, end, format, flags }` (all optional). The previous positional signature is gone.
 - `shape` and `shapeWithTrace` now take `Feature[]` instead of a comma-separated string. Use the new `Feature` class (e.g. `new Feature("liga", 0)` or `Feature.fromString("-liga")`).
 - `Buffer.setLanguage`, `Face.getName`, `Face.listNames`, and `otTagToLanguage` now use the new `Language` class instead of plain BCP 47 strings (e.g. `buffer.setLanguage(new Language("en"))`).
+- `Buffer.setScript` and `otTagToScript` now use the new `Script` class instead of plain ISO 15924 tag strings (e.g. `buffer.setScript(new Script("Latn"))` or, for the predefined ISO 15924 scripts, `buffer.setScript(Script.LATIN)`).
 - `Buffer.addText` / `Buffer.addCodePoints`: `itemLength` accepts `undefined` (or omission), instead of `null`.
 - `Face.getFeatureNameIds`: returns `undefined` on failure, instead of `null`.
 - `Font.glyphHOrigin` / `glyphVOrigin` / `glyphExtents` / `glyphFromName`: return `undefined` on failure, instead of `null`.

src/buffer.ts

@@ -4,13 +4,13 @@ import {
   track,
   hb_tag,
   utf8_ptr_to_string,
-  string_to_ascii_ptr,
   string_to_utf16_ptr,
   type ValueOf,
 } from "./helpers";
 import type { GlyphInfo, GlyphPosition } from "./types";
 import { Font } from "./font";
 import type { Language } from "./language";
+import type { Script } from "./script";
 
 export const BufferContentType = {
   INVALID: 0,
@@ -186,15 +186,10 @@ export class Buffer {
 
   /**
    * Set buffer script explicitly.
-   * @param script The buffer script
+   * @param script The buffer script.
    */
-  setScript(script: string): void {
-    const str = string_to_ascii_ptr(script);
-    exports.hb_buffer_set_script(
-      this.ptr,
-      exports.hb_script_from_string(str.ptr, -1),
-    );
-    str.free();
+  setScript(script: Script): void {
+    exports.hb_buffer_set_script(this.ptr, script.value);
   }
 
   /**

src/index.ts

@@ -9,6 +9,7 @@ export * from "./font-funcs";
 export * from "./buffer";
 export * from "./feature";
 export * from "./language";
+export * from "./script";
 export * from "./shape";
 
 init(await createHarfBuzz());