Class: TTFunk::Table::Kern::Format0

Inherits:
Object
  • Object
show all
Includes:
Reader
Defined in:
lib/ttfunk/table/kern/format0.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(attributes = {}) ⇒ Format0

Returns a new instance of Format0.



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# File 'lib/ttfunk/table/kern/format0.rb', line 12

def initialize(attributes={})
  @attributes = attributes

  num_pairs, *pairs = attributes.delete(:data).unpack("nx6n*")

  @pairs = {}
  num_pairs.times do |i|
    break if i*3+2 > pairs.length # sanity check, in case there's a bad length somewhere
    left = pairs[i*3]
    right = pairs[i*3+1]
    value = to_signed(pairs[i*3+2])
    @pairs[[left, right]] = value
  end
end

Instance Attribute Details

#attributes ⇒ Object (readonly)

Returns the value of attribute attributes.



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# File 'lib/ttfunk/table/kern/format0.rb', line 9

def attributes
  @attributes
end

#pairs ⇒ Object (readonly)

Returns the value of attribute pairs.



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# File 'lib/ttfunk/table/kern/format0.rb', line 10

def pairs
  @pairs
end

Instance Method Details

#cross_stream? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/ttfunk/table/kern/format0.rb', line 35

def cross_stream?
  @attributes[:cross]
end

#horizontal? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/ttfunk/table/kern/format0.rb', line 31

def horizontal?
  !vertical?
end

#recode(mapping) ⇒ Object 



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# File 'lib/ttfunk/table/kern/format0.rb', line 39

def recode(mapping)
  subset = []
  pairs.each do |(left, right), value|
    if mapping[left] && mapping[right]
      subset << [mapping[left], mapping[right], value]
    end
  end

  return nil if subset.empty?

  num_pairs = subset.length
  search_range = 2 * 2 ** (Math.log(num_pairs) / Math.log(2)).to_i
  entry_selector = (Math.log(search_range / 2) / Math.log(2)).to_i
  range_shift = (2 * num_pairs) - search_range

  [attributes[:version], num_pairs * 6 + 14, attributes[:coverage],
    num_pairs, search_range, entry_selector, range_shift, subset].
    flatten.pack("n*")
end

#vertical? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/ttfunk/table/kern/format0.rb', line 27

def vertical?
  @attributes[:vertical]
end