Class: TTFunk::SubsetCollection

Inherits:
Object
  • Object
show all
Defined in:
lib/ttfunk/subset_collection.rb

Instance Method Summary collapse

Constructor Details

#initialize(original) ⇒ SubsetCollection

Returns a new instance of SubsetCollection.



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# File 'lib/ttfunk/subset_collection.rb', line 5

def initialize(original)
  @original = original
  @subsets = [Subset.for(@original, :mac_roman)]
end

Instance Method Details

#[](subset) ⇒ Object 



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# File 'lib/ttfunk/subset_collection.rb', line 10

def [](subset)
  @subsets[subset]
end

#encode(characters) ⇒ Object

characters should be an array of UTF-16 characters. Returns an array of subset chunks, where each chunk is another array of two elements. The first element is the subset number, and the second element is the string of characters to render with that font subset. The strings will be encoded for their subset font, and so may not look (in the raw) like what was passed in, but they will render correctly with the indicated subset font.



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# File 'lib/ttfunk/subset_collection.rb', line 40

def encode(characters)
  return [] if characters.empty?

  # TODO: probably would be more optimal to nix the #use method,
  # and merge it into this one, so it can be done in a single
  # pass instead of two passes.
  use(characters)

  parts = []
  current_subset = 0
  current_char = 0
  char = characters[current_char]

  loop do
    while @subsets[current_subset].includes?(char)
      char = @subsets[current_subset].from_unicode(char)

      if parts.empty? || parts.last[0] != current_subset
        encoded_char = char.chr
        if encoded_char.respond_to?(:force_encoding)
          encoded_char.force_encoding("ASCII-8BIT")
        end
        parts << [current_subset, encoded_char]
      else
        parts.last[1] << char
      end

      current_char += 1
      return parts if current_char >= characters.length
      char = characters[current_char]
    end

    current_subset = (current_subset + 1) % @subsets.length
  end
end

#use(characters) ⇒ Object

characters should be an array of UTF-16 characters



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# File 'lib/ttfunk/subset_collection.rb', line 15

def use(characters)
  characters.each do |char|
    covered = false
    @subsets.each_with_index do |subset, i|
      if subset.covers?(char)
        subset.use(char)
        covered = true
        break
      end
    end

    if !covered
      @subsets << Subset.for(@original, :unicode_8bit)
      @subsets.last.use(char)
    end
  end
end