svg2ttf/lib/ttf/tables/name.js

Converts SVG font to TTF font

'use strict'

// See documentation here: http://www.microsoft.com/typography/otspec/name.htm

var _ = require('lodash')
var ByteBuffer = require('microbuffer')
var Str = require('../../str')

var TTF_NAMES = {
  COPYRIGHT: 0,
  FONT_FAMILY: 1,
  ID: 3,
  DESCRIPTION: 10,
  URL_VENDOR: 11
}

function tableSize (names) {
  var result = 6 // table header

  _.forEach(names, function (name) {
    result += 12 + name.data.length // name header and data
  })
  return result
}

function getStrings (name, id) {
  var result = []
  var str = new Str(name)

  result.push({ data: str.toUTF8Bytes(), id: id, platformID : 1, encodingID : 0, languageID : 0 }) // mac standard
  result.push({ data: str.toUCS2Bytes(), id: id, platformID : 3, encodingID : 1, languageID : 0x409 }) // windows standard
  return result
}

// Collect font names
function getNames (font) {
  var result = []

  if (font.copyright) {
    result.push.apply(result, getStrings(font.copyright, TTF_NAMES.COPYRIGHT))
  }
  if (font.familyName) {
    result.push.apply(result, getStrings(font.familyName, TTF_NAMES.FONT_FAMILY))
  }
  if (font.id) {
    result.push.apply(result, getStrings(font.id, TTF_NAMES.ID))
  }
  result.push.apply(result, getStrings(font.description, TTF_NAMES.DESCRIPTION))
  result.push.apply(result, getStrings(font.url, TTF_NAMES.URL_VENDOR))

  _.forEach(font.sfntNames, function (sfntName) {
    result.push.apply(result, getStrings(sfntName.value, sfntName.id))
  })

  result.sort(function (a, b) {
    var orderFields = ['platformID', 'encodingID', 'languageID', 'id']
    var i

    for (i = 0; i < orderFields.length; i++) {
      if (a[orderFields[i]] !== b[orderFields[i]]) {
        return a[orderFields[i]] < b[orderFields[i]] ? -1 : 1
      }
    }
    return 0
  })

  return result
}

function createNameTable (font) {
  var names = getNames(font)

  var buf = new ByteBuffer(tableSize(names))

  buf.writeUint16(0) // formatSelector
  buf.writeUint16(names.length) // nameRecordsCount
  var offsetPosition = buf.tell()

  buf.writeUint16(0) // offset, will be filled later
  var nameOffset = 0

  _.forEach(names, function (name) {
    buf.writeUint16(name.platformID) // platformID
    buf.writeUint16(name.encodingID) // platEncID
    buf.writeUint16(name.languageID) // languageID, English (USA)
    buf.writeUint16(name.id) // nameID
    buf.writeUint16(name.data.length) // reclength
    buf.writeUint16(nameOffset) // offset
    nameOffset += name.data.length
  })
  var actualStringDataOffset = buf.tell()

  // Array of bytes with actual string data
  _.forEach(names, function (name) {
    buf.writeBytes(name.data)
  })

  // write actual string data offset
  buf.seek(offsetPosition)
  buf.writeUint16(actualStringDataOffset) // offset

  return buf
}

module.exports = createNameTable