mirror of
https://github.com/2234839/web-font.git
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78 lines
2.4 KiB
TypeScript
78 lines
2.4 KiB
TypeScript
import { Font } from "../../vendor/fonteditor-core/lib/ttf/font.js";
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import type { FontEditor } from "../../vendor/fonteditor-core/lib/ttf/font.js";
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/** 优化291: TextEncoder 模块级单例 */
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const textEncoder = new TextEncoder();
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/**
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* 字体裁剪的所有可配置步骤
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* 每个步骤独立导出，方便组合使用和单独测试
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*/
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/** 从字符串提取 Unicode 码点数组 */
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export const textToCodePoints = (text: string) => {
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const result: number[] = [];
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for (let i = 0; i < text.length; i++) {
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const cp = text.codePointAt(i) as number;
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result.push(cp);
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if (cp > 0xFFFF) i++; /** 跳过代理对的低半部分 */
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}
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return result;
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};
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/**
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* 解析字体并执行 subset（最耗时的步骤）
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*/
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export const createSubsetFont = (
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fontBuffer: ArrayBuffer,
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codePoints: number[],
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sourceType: FontEditor.FontType,
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) =>
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Font.create(fontBuffer, {
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type: sourceType,
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subset: codePoints,
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});
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/**
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* 优化字体（去冗余表、清理无用字形）
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* subset 模式下 TTFReader.resolveGlyf 已完成 compound2simple，跳过
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* optimizettf 已设置 _unicodeSorted=true，sortGlyf 会直接返回
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*/
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export const optimizeFont = (font: ReturnType<typeof Font.create>) => {
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const optimized = font.optimize();
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return optimized;
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};
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/** 序列化为指定格式的二进制数据 */
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/** 优化291: 移除 async，消除不必要的微任务调度 */
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export const writeFont = (
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font: ReturnType<ReturnType<typeof Font.create>["optimize"]>,
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outType: FontEditor.FontType,
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): Uint8Array => {
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const result = font.write({ type: outType });
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if (typeof result === "string") {
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return textEncoder.encode(result);
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}
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/** 优化278: Buffer 是 Uint8Array 子类，直接返回避免多余拷贝 */
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if (result instanceof Uint8Array) {
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return result;
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}
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return new Uint8Array(result);
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};
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/**
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* 完整的字体裁剪流程（当前生产实现）
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* 解析 -> subset -> 优化 -> 序列化
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* 优化293: 移除 async，函数体内无 await，消除不必要的 Promise 包装和微任务调度
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*/
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export const fontSubset = (
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fontBuffer: ArrayBuffer,
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subString: string,
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option: { sourceType: FontEditor.FontType; outType: FontEditor.FontType },
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): Uint8Array => {
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const codePoints = textToCodePoints(subString);
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const font = createSubsetFont(fontBuffer, codePoints, option.sourceType);
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const optimized = optimizeFont(font);
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return writeFont(optimized, option.outType);
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};
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