Remove ugly “RightsLink” images in PDFs from the new ACM Digital Library.

remove_rightslink_images

#!/usr/bin/env ruby

HELP_STR = "Usage: $ remove_rightslink_images file1.pdf file2.pdf"

begin
  require 'hexapdf' # HexaPDF is AGPL licensed according to https://hexapdf.gettalong.org/
rescue LoadError
  if system("gem install --no-doc hexapdf")
    Gem.clear_paths
    require "hexapdf"
  else
    STDERR.puts("Could not install hexapdf. You may have to use sudo: $ sudo gem install --no-doc hexapdf")
    exit 1
  end
end

if ARGV.empty? || ARGV.grep("-h").any? || ARGV.grep("--help").any?
  STDERR.puts(HELP_STR)
  exit 1
end

ARGV.each do |path|
  pdf = HexaPDF::Document.open(path)

  pdf.pages.each do |page|
    page.contents = page.contents.gsub(/\nq 110 \d+ \d+ 14 \d+ \d+ cm \/Xi\d+ Do Q/, "")
  end

  pdf.write(path)
end

hexapdf seems to croak on some older PDFs. ah well