Class: Pdfrb::Font::TrueType::Kern

Inherits:
Object
  • Object
show all
Defined in:
lib/pdfrb/font/true_type/kern.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(data) ⇒ Kern

Returns a new instance of Kern.



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# File 'lib/pdfrb/font/true_type/kern.rb', line 9

def initialize(data)
  @pairs = {}
  return unless data && data.bytesize >= 4

  version = u16(data, 0)
  n_tables = u16(data, 2)

  offset = 4
  n_tables.times do
    break if offset + 6 > data.bytesize

    u16(data, offset)
    sub_length = u16(data, offset + 2)
    coverage = u16(data, offset + 4)

    if version.zero? && coverage & 0x0001 != 0
      n_pairs = u16(data, offset + 6)
      pair_offset = offset + 14

      n_pairs.times do |_p|
        break if pair_offset + 6 > data.bytesize

        left = u16(data, pair_offset)
        right = u16(data, pair_offset + 2)
        value = s16(data, pair_offset + 4)
        @pairs[[left, right]] = value
        pair_offset += 6
      end
    end

    offset += sub_length
  end
end

Instance Attribute Details

#pairs ⇒ Object (readonly)

Returns the value of attribute pairs.



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# File 'lib/pdfrb/font/true_type/kern.rb', line 7

def pairs
  @pairs
end

Instance Method Details

#kerning(left_glyph, right_glyph) ⇒ Object 



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# File 'lib/pdfrb/font/true_type/kern.rb', line 43

def kerning(left_glyph, right_glyph)
  @pairs[[left_glyph, right_glyph]] || 0
end