Method: PDF::Reader::Filter::Depredict#filter

Defined in:
lib/pdf/reader/filter/depredict.rb

#filter(data) ⇒ Object

Streams can be preprocessed to improve compression. This reverses the preprocessing

: (String) -> String



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# File 'lib/pdf/reader/filter/depredict.rb', line 21

def filter(data)
  predictor = @options[:Predictor].to_i

  case predictor
  when 0, 1 then
    data
  when 2    then
    tiff_depredict(data)
  when 10, 11, 12, 13, 14, 15 then
    png_depredict(data)
  else
    raise  MalformedPDFError, "Unrecognised predictor value (#{predictor})"
  end
end