class PDF::Reader::WidthCalculator::Composite

see Section 9.7.4.1, PDF 32000-1:2008, pp 269-270
so that it can be used.
is supposed to convert the widths for the codepoints used into the W array
program which could be used to calculate width, however, a conforming writer
codepoint widths, note that CIDFontType2 will contain a true type font
CIDFontType0 or CIDFontType2 use DW (integer) and W (array) to determine

def glyph_width(code_point) 

def glyph_width(code_point)
  return 0 if code_point.nil? || code_point < 0
  w = @widths[code_point]
  # 0 is a valid width
  if w
    w.to_f
  else
    0
  end
end

def initialize(font) 

def initialize(font)
  @font = font
  @widths = PDF::Reader::CidWidths.new(@font.cid_default_width, @font.cid_widths)
end