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# coding: utf-8
# typed: strict
# frozen_string_literal: true
require 'forwardable'
class PDF::Reader
# A Hash-like object that wraps the array of glyph widths in a CID font
# and gives us a nice way to query it for specific widths.
#
# there are two ways to calculate a cidfont_glyph_width, that are defined
# in Section 9.7.4.3 PDF 32000-1:2008 pp 271, the differences are remarked
# on below. because of these difference that may be contained within the
# same array, it is a bit difficult to parse this array.
class CidWidths
extend Forwardable
# Graphics State Operators
def_delegators :@widths, :[], :fetch
#: (Numeric, Array[Numeric]) -> void
def initialize(default, array)
@widths = parse_array(default, array.dup) #: Hash[Numeric, Numeric]
end
private
#: (Numeric, Array[Numeric]) -> Hash[Numeric, Numeric]
def parse_array(default, array)
widths = Hash.new(default)
params = []
while array.size > 0
params << array.shift
if params.size == 2 && params.last.is_a?(Array)
widths.merge! parse_first_form(params.first.to_i, Array(params.last))
params = []
elsif params.size == 3
widths.merge! parse_second_form(params[0].to_i, params[1].to_i, params[2].to_i)
params = []
end
end
widths
end
# this is the form 10 [234 63 234 346 47 234] where width of index 10 is
# 234, index 11 is 63, etc
#
#: (Integer, Array[Numeric]) -> Hash[Numeric, Numeric]
def parse_first_form(first, widths)
widths.inject({}) { |accum, glyph_width|
accum[first + accum.size] = glyph_width
accum
}
end
# this is the form 10 20 123 where all index between 10 and 20 have width 123
#
#: (Integer, Integer, Numeric) -> Hash[Numeric, Numeric]
def parse_second_form(first, final, width)
if first > final
raise MalformedPDFError, "CidWidths: #{first} must be less than #{final}"
end
(first..final).inject({}) { |accum, index|
accum[index] = width
accum
}
end
end
end
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