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

Make it executable and put it in your path, then:

$ remove_rightslink_images *.pdf

The PDFs are modified in place. (If you don't like that, change line 30 to write to some other file path.)

hexapdf seems to croak on some older PDFs. ah well