Class: JekyllPandocMultipleFormats::Imposition

Inherits:
Printer
  • Object
show all
Defined in:
lib/jekyll-pandoc-multiple-formats/imposition.rb

Constant Summary

Constants inherited from Printer

Printer::SHEET_SIZES, Printer::TEMPLATE

Instance Attribute Summary collapse

Attributes inherited from Printer

#extra_options, #nup, #original_file, #output_file, #pages, #papersize, #relative_path, #sheetsize, #template

Instance Method Summary collapse

Methods inherited from Printer

#is_landscape?, #render_template, #round_to_nearest, #write

Constructor Details

#initialize(file, papersize = nil, sheetsize = nil, signature = nil, extra_options = nil) ⇒ Imposition

Returns a new instance of Imposition.



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# File 'lib/jekyll-pandoc-multiple-formats/imposition.rb', line 29

def initialize(file, papersize = nil, sheetsize = nil, signature = nil, extra_options = nil)
  super(file, papersize, sheetsize, extra_options)
  @output_file   = file.gsub(/\.pdf\Z/, '-imposed.pdf')
  # Total pages must be modulo 4
  @rounded_pages = round_to_nearest(@pages, 4)
  @blank_pages   = @rounded_pages - @pages
  # If we don't use a signature, make a single fold
  @signature     = signature || @rounded_pages
  # Also if we specified 0
  @signature     = @rounded_pages if signature == 0

  render_template
  self
end

Instance Attribute Details

#blank_pages ⇒ Object

Returns the value of attribute blank_pages.



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# File 'lib/jekyll-pandoc-multiple-formats/imposition.rb', line 27

def blank_pages
  @blank_pages
end

#rounded_pages ⇒ Object

Returns the value of attribute rounded_pages.



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# File 'lib/jekyll-pandoc-multiple-formats/imposition.rb', line 27

def rounded_pages
  @rounded_pages
end

#signature ⇒ Object

Returns the value of attribute signature.



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# File 'lib/jekyll-pandoc-multiple-formats/imposition.rb', line 27

def signature
  @signature
end

Instance Method Details

#to_nup ⇒ Object 



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# File 'lib/jekyll-pandoc-multiple-formats/imposition.rb', line 44

def to_nup
  # 14 pages example:
  # [ {}, 1, 2, {}, 14, 3, 4, 13, 12, 5, 6, 11, 10, 7, 8, 9 ]
  #
  # * Add {} to missing pages
  #   [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, {}, {}]
  # * Take first half [ 1, 2, 3, 4, 5, 6, 7, 8 ]
  # * Reverse second half [ {}, {}, 14, 13, 12, 11, 10, 9 ]
  # * Intercalate the first half into the second half by two
  #   elements
  #   [ {}, 1, 2, {}, 14, 3, 4, 13, 12, 5, 6, 11, 10, 7, 8, 9 ]
  #
  # An array of numbered pages padded with blank pages ('{}')
  #
  # [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 ] + [ '{}', '{}' ]
  padded = @pages.times.map{|i|i+1} + Array.new(@blank_pages, '{}')

  # If we have a signature, we have to split in groups up to the
  # amount of pages per signature, and then continue with the rest
  #
  # If we have no signature, we assume it's equal to the total
  # amount of pages, so you only have one fold
  signed = padded.each_slice(@signature).to_a
  folds = []
  signed.each do |fold|
    #
    # Split in halves
    # [ [ 1, 2, 3, 4, 5, 6, 7, 8 ],
    #   [ 9, 10, 11, 12, 13, 14, '{}', '{}' ] ]
    halved = fold.each_slice(fold.size / 2).to_a
    # Add a nil as last page.  When we reverse it and intercalate by
    # two pages, we'll have [nil, last_page] instead of
    # [last_page,second_to_last_page]
    #
    # [ [ 1, 2, 3, 4, 5, 6, 7, 8 ],
    #   [ 9, 10, 11, 12, 13, 14, '{}', '{}', nil ] ]
    halved.last << nil
    # Reverse the second half and intercalate by two pages into the
    # first one.  Then remove nil elements and flatten the array.
    #
    # [ [ 1, 2, 3, 4, 5, 6, 7, 8 ],
    #   [ nil, '{}', '{}', 14, 13, 12, 11, 10 ] ]
    #
    # [ {}, 1, 2, {}, 14, 3, 4, 13, 12, 5, 6, 11, 10, 7, 8, 9 ]
    folds << halved.last.reverse.each_slice(2).zip(halved.first.each_slice(2).to_a).flatten.compact
  end

  # Create the matrix of pages (N-Up) per fold
  #
  # ["{}", 1, "{}", 1, 2, "{}", 2, "{}", 14, 3, 14, 3, 4, 13, 4, 13, 12, 5, 12, 5, 6, 11, 6, 11, 10, 7, 10, 7, 8, 9, 8, 9]
  folds.map { |o| o.each_slice(2).map{ |i| a=[]; (@nup/2).times { a = a+i }; a }}.flatten
end