module TTFunk::Table::Cmap::Format12

Attributes

code_map[R]
language[R]

Public Class Methods

encode(charmap) click to toggle source
# File lib/ttfunk/table/cmap/format12.rb, line 8
def self.encode(charmap)
  next_id = 0
  glyph_map = { 0 => 0 }
  range_firstglyphs = []
  range_firstcodes = []
  range_lengths = []
  last_glyph = last_code = -999

  new_map = charmap.keys.sort.each_with_object({}) do |code, map|
    glyph_map[charmap[code]] ||= next_id += 1
    map[code] = { old: charmap[code], new: glyph_map[charmap[code]] }

    if code > last_code + 1 || glyph_map[charmap[code]] > last_glyph + 1
      range_firstcodes << code
      range_firstglyphs << glyph_map[charmap[code]]
      range_lengths << 1
    else
      range_lengths.push(range_lengths.pop) + 1
    end
    last_code = code
    last_glyph = glyph_map[charmap[code]]
  end

  subtable = [
    12, 0, 16 + 12 * range_lengths.size, 0, range_lengths.size
  ].pack('nnNNN')
  range_lengths.each_with_index do |length, i|
    firstglyph = range_firstglyphs[i]
    firstcode = range_firstcodes[i]
    subtable << [
      firstcode, firstcode + length - 1, firstglyph
    ].pack('NNN')
  end

  { charmap: new_map, subtable: subtable, max_glyph_id: next_id + 1 }
end

Public Instance Methods

[](code) click to toggle source
# File lib/ttfunk/table/cmap/format12.rb, line 45
def [](code)
  @code_map[code] || 0
end
supported?() click to toggle source
# File lib/ttfunk/table/cmap/format12.rb, line 49
def supported?
  true
end

Private Instance Methods

parse_cmap!() click to toggle source
# File lib/ttfunk/table/cmap/format12.rb, line 55
def parse_cmap!
  fractional_version, @language, groupcount = read(14, 'nx4NN')
  if fractional_version != 0
    raise NotImplementedError,
      "cmap version 12.#{fractional_version} is not supported"
  end
  @code_map = {}
  (1..groupcount).each do
    startchar, endchar, startglyph = read(12, 'NNN')
    (0..(endchar - startchar)).each do |offset|
      @code_map[startchar + offset] = startglyph + offset
    end
  end
end