fonteditor-core/lib/ttf/woff2ttf.js

fonts (ttf, woff, woff2, eot, svg, otf) parse, write, transform, glyph adjust.

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = woff2ttf;
var _reader = _interopRequireDefault(require("./reader"));
var _writer = _interopRequireDefault(require("./writer"));
var _error = _interopRequireDefault(require("./error"));
function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
/**
 * @file woff转换ttf
 * @author mengke01(kekee000@gmail.com)
 */

/**
 * woff格式转换成ttf字体格式
 *
 * @param {ArrayBuffer} woffBuffer woff缓冲数组
 * @param {Object} options 选项
 * @param {Object} options.inflate 解压相关函数
 *
 * @return {ArrayBuffer} ttf格式byte流
 */
function woff2ttf(woffBuffer) {
  var options = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : {};
  var reader = new _reader.default(woffBuffer);
  var signature = reader.readUint32(0);
  var flavor = reader.readUint32(4);
  if (signature !== 0x774F4646 || flavor !== 0x10000 && flavor !== 0x4f54544f) {
    reader.dispose();
    _error.default.raise(10102);
  }
  var numTables = reader.readUint16(12);
  var ttfSize = reader.readUint32(16);
  var tableEntries = [];
  var tableEntry;
  var i;
  var l;

  // 读取woff表索引信息
  for (i = 0; i < numTables; ++i) {
    reader.seek(44 + i * 20);
    tableEntry = {
      tag: reader.readString(reader.offset, 4),
      offset: reader.readUint32(),
      compLength: reader.readUint32(),
      length: reader.readUint32(),
      checkSum: reader.readUint32()
    };

    // ttf 表数据
    var deflateData = reader.readBytes(tableEntry.offset, tableEntry.compLength);
    // 需要解压
    if (deflateData.length < tableEntry.length) {
      if (!options.inflate) {
        reader.dispose();
        _error.default.raise(10105);
      }
      tableEntry.data = options.inflate(deflateData);
    } else {
      tableEntry.data = deflateData;
    }
    tableEntry.length = tableEntry.data.length;
    tableEntries.push(tableEntry);
  }
  var writer = new _writer.default(new ArrayBuffer(ttfSize));
  // 写头部
  var entrySelector = Math.floor(Math.log(numTables) / Math.LN2);
  var searchRange = Math.pow(2, entrySelector) * 16;
  var rangeShift = numTables * 16 - searchRange;
  writer.writeUint32(flavor);
  writer.writeUint16(numTables);
  writer.writeUint16(searchRange);
  writer.writeUint16(entrySelector);
  writer.writeUint16(rangeShift);

  // 写ttf表索引
  var tblOffset = 12 + 16 * tableEntries.length;
  for (i = 0, l = tableEntries.length; i < l; ++i) {
    tableEntry = tableEntries[i];
    writer.writeString(tableEntry.tag);
    writer.writeUint32(tableEntry.checkSum);
    writer.writeUint32(tblOffset);
    writer.writeUint32(tableEntry.length);
    tblOffset += tableEntry.length + (tableEntry.length % 4 ? 4 - tableEntry.length % 4 : 0);
  }

  // 写ttf表数据
  for (i = 0, l = tableEntries.length; i < l; ++i) {
    tableEntry = tableEntries[i];
    writer.writeBytes(tableEntry.data);
    if (tableEntry.length % 4) {
      writer.writeEmpty(4 - tableEntry.length % 4);
    }
  }
  return writer.getBuffer();
}