mirror of
https://github.com/2234839/web-font.git
synced 2026-09-13 04:15:42 +08:00
8a7efea9d0
GPOS/GSUB 表类 read 原用 reader.readBytes (= new Uint8Array(view.buffer, off, len).slice())， .slice() 拷贝整个表字节（初夏 GPOS 68KB、GSUB 31KB）。V8 中 68KB slice 耗 ~40μs， 而 subarray 零拷贝仅 ~0.3μs（130× 差距）。 GPOS/GSUB 是原始字节透传：subsetGPOS/subsetGSUB 只读 OTReader + 写全新 OTWriter， write 只 writeBytes 只读，optimize 不碰，整个 read→optimize→subset→write 生命周期 从不原地修改底层字节，故可安全返回共享 ArrayBuffer 的 subarray 视图。 初夏 full read 0.124→0.063ms (-49%)，readBuffer 0.165→0.098ms。 全基准 SSIM 与输出字节完全不变。 Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
38 lines
1.7 KiB
TypeScript
38 lines
1.7 KiB
TypeScript
import fs from 'node:fs';
|
||
import * as TTFReaderNS from './vendor/fonteditor-core/lib/ttf/ttfreader.js';
|
||
const TTFReader: any = TTFReaderNS.default.default ?? TTFReaderNS.default;
|
||
const supportNS: any = await import('./vendor/fonteditor-core/lib/ttf/table/support.js');
|
||
const support: any = supportNS.default.default ?? supportNS.default;
|
||
|
||
const buf = fs.readFileSync('/mnt/d/字体资源/初夏明朝/初夏明朝-Regular.ttf');
|
||
const ab = buf.buffer.slice(buf.byteOffset, buf.byteOffset+buf.byteLength) as ArrayBuffer;
|
||
const cps = Array.from('，。！？、；：“”‘’').map(c => c.codePointAt(0)!);
|
||
|
||
// monkey-patch 每个表类的 read，累加耗时
|
||
const stats: Record<string, number[]> = {};
|
||
for (const tn of Object.keys(support)) {
|
||
const TableClass: any = support[tn];
|
||
if (!TableClass || !TableClass.prototype || !TableClass.prototype.read) continue;
|
||
const orig = TableClass.prototype.read;
|
||
TableClass.prototype.read = function(reader: any, ttf: any) {
|
||
const t0 = performance.now();
|
||
const r = orig.call(this, reader, ttf);
|
||
const dt = performance.now() - t0;
|
||
(stats[tn] ??= []).push(dt);
|
||
return r;
|
||
};
|
||
}
|
||
|
||
function median(a: number[]) { return a.slice().sort((x,y)=>x-y)[Math.floor(a.length/2)]; }
|
||
|
||
// 多次跑 readBuffer 累加统计
|
||
for (let i = 0; i < 25; i++) {
|
||
const r = new (TTFReader as any)({ subset: cps, kerning: true });
|
||
r.readBuffer(ab);
|
||
}
|
||
|
||
console.log('=== 初夏标点 各表 read 耗时（25次中位数）===');
|
||
const rows = Object.entries(stats).map(([n, a]) => ({ n, med: median(a), min: Math.min(...a) }));
|
||
rows.sort((a,b)=>b.med-a.med);
|
||
for (const r of rows) console.log(` ${r.n}: ${r.med.toFixed(3)}ms (min ${r.min.toFixed(3)}, ${stats[r.n].length}次)`);
|