Class: HexaPDF::Font::CMap::Writer

Inherits:
Object
  • Object
show all
Defined in:
lib/hexapdf/font/cmap/writer.rb

Overview

Creates a CMap file.

Currently only ToUnicode CMaps are supported.

Constant Summary collapse

MAX_ENTRIES_IN_SECTION =

Maximum number of entries in one section.

100

Instance Method Summary collapse

Instance Method Details

#create_to_unicode_cmap(mapping) ⇒ Object

Returns a ToUnicode CMap for the given input code to Unicode codepoint mapping which needs to be sorted by input codes.

Note that the returned CMap always uses a 16-bit input code space!



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# File 'lib/hexapdf/font/cmap/writer.rb', line 52

def create_to_unicode_cmap(mapping)
  return to_unicode_template % '' if mapping.empty?

  chars, ranges = compute_section_entries(mapping)

  result = create_sections("bfchar", chars.size / 2) do |index|
    index *= 2
    sprintf("<%04X>", chars[index]) << "<" <<
      ((+'').force_encoding(::Encoding::UTF_16BE) << chars[index + 1]).unpack1('H*') <<
      ">\n"
  end

  result << create_sections("bfrange", ranges.size / 3) do |index|
    index *= 3
    sprintf("<%04X><%04X>", ranges[index], ranges[index + 1]) << "<" <<
      ((+'').force_encoding(::Encoding::UTF_16BE) << ranges[index + 2]).unpack1('H*') <<
      ">\n"
  end

  to_unicode_template % result.chop!
end