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# frozen_string_literal: true
module TTFunk
class Table
class Cmap
# Format 0: Byte encoding table.
#
# This module conditionally extends {TTFunk::Table::Cmap::Subtable}.
module Format00
# Language.
# @return [Integer]
attr_reader :language
# Code map.
# @return [Array<Integer>]
attr_reader :code_map
# Encode the encoding record to format 0.
#
# @param charmap [Hash{Integer => Integer}] a hash mapping character
# codes to glyph ids (where the glyph ids are from the original font).
# @return [Hash]
# * `:charmap` (<tt>Hash{Integer => Hash}</tt>) keys are the characrers in
# `charset`, values are hashes:
# * `:old` (<tt>Integer</tt>) - glyph ID in the original font.
# * `:new` (<tt>Integer</tt>) - glyph ID in the subset font.
# that maps the characters in charmap to a
# * `:subtable` (<tt>String</tt>) - serialized encoding record.
# * `:max_glyph_id` (<tt>Integer</tt>) - maximum glyph ID in the new font.
def self.encode(charmap)
next_id = 0
glyph_indexes = Array.new(256, 0)
glyph_map = { 0 => 0 }
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]] }
glyph_indexes[code] = glyph_map[charmap[code]]
map
end
# format, length, language, indices
subtable = [0, 262, 0, *glyph_indexes].pack('nnnC*')
{ charmap: new_map, subtable: subtable, max_glyph_id: next_id + 1 }
end
# Get glyph ID for character code.
#
# @param code [Integer] character code.
# @return [Integer] glyph ID.
def [](code)
@code_map[code] || 0
end
# Is this encoding record format supported?
#
# @return [true]
def supported?
true
end
private
def parse_cmap!
@language = read(4, 'x2n')
@code_map = read(256, 'C*')
end
end
end
end
end
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