Bind hb_font_get_glyph() and friends

Bind hb_font_get_glyph(), hb_font_get_nominal_glyph(), and
hb_font_get_variation_glyph().

Author: khaledhosny

harfbuzz.symbols

@@ -38,7 +38,10 @@ _hb_font_set_variations
 _hb_font_get_h_extents
 _hb_font_get_v_extents
 _hb_font_get_glyph_extents
+_hb_font_get_glyph
 _hb_font_get_glyph_from_name
+_hb_font_get_nominal_glyph
+_hb_font_get_variation_glyph
 _hb_font_get_glyph_h_advance
 _hb_font_get_glyph_v_advance
 _hb_font_get_glyph_h_origin

src/font.ts

@@ -295,6 +295,88 @@ export class Font {
     return extents;
   }
 
+  /**
+   * Fetches the glyph ID for a Unicode code point in the specified
+   * font, with an optional variation selector.
+   *
+   * If `variationSelector` is 0, it is equivalent to
+   * {@link Font.nominalGlyph}; otherwise it is equivalent to
+   * {@link Font.variationGlyph}.
+   *
+   * @param unicode The Unicode code point to query.
+   * @param variationSelector A variation-selector code point.
+   * @returns The glyph ID, or undefined if not found.
+   */
+  glyph(unicode: number, variationSelector: number = 0): number | undefined {
+    const sp = Module.stackSave();
+    const glyphIdPtr = Module.stackAlloc(4);
+    let glyphId: number | undefined;
+    if (
+      exports.hb_font_get_glyph(
+        this.ptr,
+        unicode,
+        variationSelector,
+        glyphIdPtr,
+      )
+    ) {
+      glyphId = Module.HEAPU32[glyphIdPtr / 4];
+    }
+    Module.stackRestore(sp);
+    return glyphId;
+  }
+
+  /**
+   * Fetches the nominal glyph ID for a Unicode code point in the
+   * specified font.
+   *
+   * This version of the function should not be used to fetch glyph IDs
+   * for code points modified by variation selectors. For variation-selector
+   * support, use {@link Font.variationGlyph} or {@link Font.glyph}.
+   *
+   * @param unicode The Unicode code point to query.
+   * @returns The glyph ID, or undefined if not found.
+   */
+  nominalGlyph(unicode: number): number | undefined {
+    const sp = Module.stackSave();
+    const glyphIdPtr = Module.stackAlloc(4);
+    let glyphId: number | undefined;
+    if (exports.hb_font_get_nominal_glyph(this.ptr, unicode, glyphIdPtr)) {
+      glyphId = Module.HEAPU32[glyphIdPtr / 4];
+    }
+    Module.stackRestore(sp);
+    return glyphId;
+  }
+
+  /**
+   * Fetches the glyph ID for a Unicode code point when followed by
+   * by the specified variation-selector code point, in the specified
+   * font.
+   *
+   * @param unicode The Unicode code point to query.
+   * @param variationSelector The variation-selector code point to query.
+   * @returns The glyph ID, or undefined if not found.
+   */
+  variationGlyph(
+    unicode: number,
+    variationSelector: number,
+  ): number | undefined {
+    const sp = Module.stackSave();
+    const glyphIdPtr = Module.stackAlloc(4);
+    let glyphId: number | undefined;
+    if (
+      exports.hb_font_get_variation_glyph(
+        this.ptr,
+        unicode,
+        variationSelector,
+        glyphIdPtr,
+      )
+    ) {
+      glyphId = Module.HEAPU32[glyphIdPtr / 4];
+    }
+    Module.stackRestore(sp);
+    return glyphId;
+  }
+
   /**
    * Return glyph ID from name.
    * @param name Name of the requested glyph in the font.

test/index.test.js

@@ -491,6 +491,23 @@ describe("Font", function () {
     expect(font.glyphFromName("NonExistentGlyph")).to.equal(undefined);
   });
 
+  it("glyph/nominalGlyph/variationGlyph return ids for code points", 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);
+    const codepoint = "A".codePointAt(0);
+    expect(font.nominalGlyph(codepoint)).to.equal(36);
+    expect(font.nominalGlyph(0x10ffff)).to.equal(undefined);
+    expect(font.variationGlyph(codepoint, 0xfe00)).to.equal(undefined);
+    expect(font.glyph(codepoint)).to.equal(font.nominalGlyph(codepoint));
+    expect(font.glyph(codepoint, 0xfe00)).to.equal(
+      font.variationGlyph(codepoint, 0xfe00),
+    );
+    expect(font.glyph(0x10ffff)).to.equal(font.nominalGlyph(0x10ffff));
+  });
+
   it("setVariations affects advances", function () {
     let blob = new hb.Blob(
       fs.readFileSync(