Compose runtime font glyphs

import {
  createFontGlyphSource,
  decodeBitmapGlyphs,
  decodeUnihexGlyphs,
} from "@groundsgg/motd/fonts";

// Original synthetic glyphs; no game resources are required.
const bitmap = decodeBitmapGlyphs(
  { height: 1, ascent: 1, chars: ["A"] },
  { width: 1, height: 1, pixels: new Uint8Array([20, 40, 60, 128]) },
);
const unihex = decodeUnihexGlyphs({}, [
  new TextEncoder().encode(
    "0041:" + "38".repeat(16) + "\n01F600:" + "00".repeat(16),
  ),
]);
if (!bitmap.value || !unihex.value) throw Error("Decode failed");

const result = createFontGlyphSource([
  { type: "space", advances: { " ": 4 } },
  { type: "bitmap", glyphs: bitmap.value },
  { type: "unihex", glyphs: unihex.value },
]);
if (!result.value) throw Error("Composition failed");

const source = result.value;
console.log(source.codePoints); // [32, 65, 128512]
const a = source.glyphFor(65);
console.log(a.advance, a.boldOffset); // 2, 1; bitmap layer wins over Unihex A
console.log([...a.bitmap.pixels().value]); // [20, 40, 60, 128]
console.log(source.glyphFor(128512).boldOffset); // 0.5; Unihex 😀
console.log(source.glyphFor(32).bitmap); // null; explicit space glyph
console.log(source.glyphFor(66)); // undefined; absent B