MuPDF is a partial set of bindings to the MuPDF viewer's API.

Add this line to your application's Gemfile:

gem 'mupdf'

And then execute:

$ bundle

Or install it yourself as:

$ gem install mupdf

Save each page with the width set to 768. A saner API for sizes is forthcoming

document = MuPDF::Document.open( 'test/example.pdf' )
document.each_page do |page|
    page.save( "test/page-#{page.number}.png", 768 )
end

1. Fork it ( http://github.com//mupdf/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request