Add Font.face property

Author: khaledhosny

harfbuzz.symbols

@@ -27,10 +27,12 @@ _hb_face_create
 _hb_face_collect_unicodes
 _hb_face_destroy
 _hb_face_get_upem
+_hb_face_reference
 _hb_face_reference_table
 _hb_font_create
 _hb_font_destroy
 _hb_font_reference
+_hb_font_get_face
 _hb_font_create_sub_font
 _hb_font_glyph_to_string
 _hb_font_set_scale

src/face.ts

@@ -39,8 +39,15 @@ export class Face {
    * @param index The index of the font in the blob. (0 for most files,
    *  or a 0-indexed font number if the `blob` came from a font collection file.)
    */
-  constructor(blob: Blob, index: number = 0) {
-    this.ptr = exports.hb_face_create(blob.ptr, index);
+  constructor(blob: Blob, index?: number);
+  /** @internal Wrap an existing face pointer. */
+  constructor(existingPtr: number);
+  constructor(arg: Blob | number, index: number = 0) {
+    if (typeof arg === "number") {
+      this.ptr = exports.hb_face_reference(arg);
+    } else {
+      this.ptr = exports.hb_face_create(arg.ptr, index);
+    }
     this.upem = exports.hb_face_get_upem(this.ptr);
     track(this, exports.hb_face_destroy);
   }

src/font.ts

@@ -7,7 +7,7 @@ import {
 } from "./helpers";
 import type { FontExtents, GlyphExtents, SvgPathCommand } from "./types";
 import type { Direction } from "./buffer";
-import type { Face } from "./face";
+import { Face } from "./face";
 import type { FontFuncs } from "./font-funcs";
 import type { Variation } from "./variation";
 
@@ -29,6 +29,7 @@ interface DrawPtrs {
  */
 export class Font {
   readonly ptr: number;
+  private _face?: Face;
   private drawPtrs: DrawPtrs = {
     pathBuffer: "",
   };
@@ -44,6 +45,7 @@ export class Font {
       this.ptr = exports.hb_font_reference(arg);
     } else {
       this.ptr = exports.hb_font_create(arg.ptr);
+      this._face = arg;
     }
     const ptr = this.ptr;
     const drawState = this.drawPtrs;
@@ -60,6 +62,14 @@ export class Font {
     });
   }
 
+  /** The {@link Face} associated with this font. */
+  get face(): Face {
+    if (!this._face) {
+      this._face = new Face(exports.hb_font_get_face(this.ptr));
+    }
+    return this._face;
+  }
+
   /**
    * Create a sub font that inherits this font's properties.
    * @returns A new Font object representing the sub font.

test/index.test.js

@@ -363,6 +363,16 @@ describe("Face", function () {
 });
 
 describe("Font", function () {
+  it("exposes its face", function () {
+    let blob = new hb.Blob(
+      fs.readFileSync(path.join(__dirname, "fonts/noto/NotoSans-Regular.ttf")),
+    );
+    let face = new hb.Face(blob);
+    let font = new hb.Font(face);
+    expect(font.face).to.equal(face);
+    expect(font.subFont().face.ptr).to.equal(face.ptr);
+  });
+
   it("subFont creates a sub font", function () {
     let blob = new hb.Blob(
       fs.readFileSync(path.join(__dirname, "fonts/noto/NotoSans-Regular.ttf")),