Module: CombinePDF::PDFFilter

Defined in:
lib/combine_pdf/combine_pdf_filter.rb

Overview

This is an internal class. you don’t need it.

Class Method Summary collapse

Class Method Details

.deflate_object(object = nil, filter = :none) ⇒ Object

deflate / compress an object.

isn’t supported yet!

object

object to compress.

filter

filter to use.



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# File 'lib/combine_pdf/combine_pdf_filter.rb', line 26

def deflate_object object = nil, filter = :none
  false
end

.inflate_object(object = nil) ⇒ Object

inflate / decompress an object

object

object to decompress.



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# File 'lib/combine_pdf/combine_pdf_filter.rb', line 33

def inflate_object object = nil
  filter_array = object[:Filter]
  if filter_array.is_a?(Hash) && filter_array[:is_reference_only]
    filter_array = filter_array[:referenced_object]
  end
  if filter_array.is_a?(Symbol)
    filter_array = [filter_array]
  end
  filter_array = [] if filter_array.nil?
  params_array = object[:DecodeParms]
  if params_array.is_a?(Hash) && params_array[:is_reference_only]
    params_array = params_array[:referenced_object]
  end
  unless params_array.is_a?(Array)
    params_array = [params_array]
  end
  while filter_array[0]
    case filter_array[0]
    when :FlateDecode
      raise_unsupported_error params_array[0] unless params_array[0].nil?
      if params_array[0] && params_array[0][:Predictor].to_i > 1
        bits = params_array[0][:BitsPerComponent] || 8
        predictor = params_array[0][:Predictor].to_i
        columns = params_array[0][:Columns] || 1
        if (2..9).include? params_array[0][:Predictor].to_i
          ####
          # prepare TIFF group
        elsif (10..15).include? params_array[0][:Predictor].to_i == 2
          ####
          # prepare PNG group
        end
      else
        inflator = Zlib::Inflate.new

        object[:raw_stream_content] = inflator.inflate object[:raw_stream_content]
        begin
          inflator.finish
        rescue
        end
        inflator.close
        object[:Length] = object[:raw_stream_content].bytesize
      end
    when nil
      true
    else
      return false
    end
    params_array.shift
    filter_array.shift
  end
  object.delete(:Filter)
  true
end