177 lines
4.6 KiB
JavaScript
177 lines
4.6 KiB
JavaScript
/**
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* @file ttfreader.js
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* @author mengke01
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* @date
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* @description
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* ttf定义
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*
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* thanks to：
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* ynakajima/ttf.js
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* https://github.com/ynakajima/ttf.js
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*/
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define(
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function (require) {
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var Directory = require('./table/directory');
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var supportTables = require('./table/support');
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var Reader = require('./reader');
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var postName = require('./enum/postName');
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var error = require('./error');
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/**
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* 初始化
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*
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* @param {ArrayBuffer} buffer buffer对象
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* @return {Object} ttf对象
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*/
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function read(buffer) {
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var reader = new Reader(buffer, 0, buffer.byteLength, false);
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var ttf = {};
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// version
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ttf.version = reader.readFixed(0);
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if (ttf.version !== 0x1) {
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error.raise(10101);
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}
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// num tables
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ttf.numTables = reader.readUint16();
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if (ttf.numTables <= 0 || ttf.numTables > 100) {
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error.raise(10101);
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}
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// searchRenge
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ttf.searchRenge = reader.readUint16();
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// entrySelector
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ttf.entrySelector = reader.readUint16();
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// rengeShift
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ttf.rengeShift = reader.readUint16();
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ttf.tables = new Directory(reader.offset).read(reader, ttf);
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if (!ttf.tables.glyf || !ttf.tables.head || !ttf.tables.cmap || !ttf.tables.hmtx) {
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error.raise(10204);
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}
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// 读取支持的表数据
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Object.keys(supportTables).forEach(function (tableName) {
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if (ttf.tables[tableName]) {
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var offset = ttf.tables[tableName].offset;
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ttf[tableName] = new supportTables[tableName](offset).read(reader, ttf);
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}
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});
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if (!ttf.glyf) {
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error.raise(10201);
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}
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reader.dispose();
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return ttf;
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}
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/**
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* 关联glyf相关的信息
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* @param {Object} ttf ttf对象
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*/
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function resolveGlyf(ttf) {
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var codes = ttf.cmap;
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var glyf = ttf.glyf;
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// unicode
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Object.keys(codes).forEach(function (c) {
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var i = codes[c];
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if (!glyf[i].unicode) {
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glyf[i].unicode = [];
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}
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glyf[i].unicode.push(+c);
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});
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// advanceWidth
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ttf.hmtx.forEach(function (item, i) {
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glyf[i].advanceWidth = item.advanceWidth;
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glyf[i].leftSideBearing = item.leftSideBearing;
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});
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// name
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if (ttf.post && 2 === ttf.post.format) {
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var nameIndex = ttf.post.glyphNameIndex;
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var names = ttf.post.names;
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nameIndex.forEach(function (nameIndex, i) {
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if (nameIndex <= 257) {
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glyf[i].name = postName[nameIndex];
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}
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else {
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glyf[i].name = names[nameIndex - 258] || '';
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}
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});
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}
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}
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/**
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* 清除非必须的表
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* @param {Object} ttf ttf对象
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*/
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function cleanTables(ttf) {
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delete ttf.tables;
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delete ttf.hmtx;
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delete ttf.loca;
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delete ttf.post.glyphNameIndex;
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delete ttf.post.names;
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if (!this.options.hinting) {
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delete ttf.fpgm;
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delete ttf.cvt;
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delete ttf.prep;
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ttf.glyf.forEach(function (glyf) {
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delete glyf.instructions;
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});
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}
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}
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/**
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* TTF的构造函数
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* @param {Object} options 写入参数
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* @param {boolean} hinting 保留hinting信息
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* @constructor
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*/
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function TTFReader(options) {
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this.options = options || {
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hinting: false // 不保留hints信息
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};
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}
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/**
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* 获取解析后的ttf文档
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* @param {ArrayBuffer} buffer buffer对象
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*
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* @return {Object} ttf文档
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*/
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TTFReader.prototype.read = function (buffer) {
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this.ttf = read.call(this, buffer);
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resolveGlyf.call(this, this.ttf);
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cleanTables.call(this, this.ttf);
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return this.ttf;
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};
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/**
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* 注销
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*/
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TTFReader.prototype.dispose = function () {
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delete this.ttf;
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};
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return TTFReader;
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}
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);
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