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/*
* SPDX-FileCopyrightText: syuilo and misskey-project
* SPDX-License-Identifier: AGPL-3.0-only
*/
import { promises as fsp } from 'fs';
import { compress } from 'wawoff2';
export async function generateSubsettedFont(ttfPath: string, unicodeRangeValues: Map<string, number[]>) {
const ttf = await fsp.readFile(ttfPath);
const {
instance: { exports: harfbuzzWasm },
}: any = await WebAssembly.instantiate(await fsp.readFile('./node_modules/harfbuzzjs/hb-subset.wasm'));
const heapu8 = new Uint8Array(harfbuzzWasm.memory.buffer);
const subsetFonts = new Map<string, Buffer>();
let i = 0;
for (const [key, unicodeValues] of unicodeRangeValues) {
i++;
console.log(`Generating subset ${i} of ${unicodeRangeValues.size}...`);
// サブセット入力を作成
const input = harfbuzzWasm.hb_subset_input_create_or_fail();
if (input === 0) {
throw new Error('hb_subset_input_create_or_fail (harfbuzz) returned zero');
}
// フォントバッファにフォントデータをセット
const fontBuffer = harfbuzzWasm.malloc(ttf.byteLength);
heapu8.set(new Uint8Array(ttf), fontBuffer);
// フォントフェイスを作成
const blob = harfbuzzWasm.hb_blob_create(fontBuffer, ttf.byteLength, 2, 0, 0);
const face = harfbuzzWasm.hb_face_create(blob, 0);
harfbuzzWasm.hb_blob_destroy(blob);
// Unicodeセットに指定されたUnicodeポイントを追加
const inputUnicodes = harfbuzzWasm.hb_subset_input_unicode_set(input);
for (const unicode of unicodeValues) {
harfbuzzWasm.hb_set_add(inputUnicodes, unicode);
}
// サブセットを作成
let subset;
try {
subset = harfbuzzWasm.hb_subset_or_fail(face, input);
if (subset === 0) {
harfbuzzWasm.hb_face_destroy(face);
harfbuzzWasm.free(fontBuffer);
throw new Error('hb_subset_or_fail (harfbuzz) returned zero');
}
} finally {
harfbuzzWasm.hb_subset_input_destroy(input);
}
// サブセットフォントデータを取得
const result = harfbuzzWasm.hb_face_reference_blob(subset);
const offset = harfbuzzWasm.hb_blob_get_data(result, 0);
const subsetByteLength = harfbuzzWasm.hb_blob_get_length(result);
if (subsetByteLength === 0) {
harfbuzzWasm.hb_face_destroy(face);
harfbuzzWasm.hb_blob_destroy(result);
harfbuzzWasm.free(fontBuffer);
throw new Error('hb_blob_get_length (harfbuzz) returned zero');
}
// サブセットフォントをバッファに格納
subsetFonts.set(key, Buffer.from(await compress(heapu8.slice(offset, offset + subsetByteLength))));
// メモリを解放
harfbuzzWasm.hb_blob_destroy(result);
harfbuzzWasm.hb_face_destroy(subset);
harfbuzzWasm.hb_face_destroy(face);
harfbuzzWasm.free(fontBuffer);
}
return subsetFonts;
}
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