# From rtex-2.1.0
 
        def render_with_rtex(options=nil, *args, &block)
          result = render_without_rtex(options, *args, &block)
          if result.is_a?(String) && Thread.current[:_rendering_rtex]
            Thread.current[:_rendering_rtex] = false
            options ||= {}
            ::RTeX::Document.new(result, options.merge(:processed => true)).to_pdf do |filename|
              serve_file = Tempfile.new('rtex-pdf')
              FileUtils.mv filename, serve_file.path
              send_file serve_file.path,
                :disposition => (options[:disposition] rescue nil) || 'inline',
                :url_based_filename => true,
                :filename => (options[:filename] rescue nil),
                :type => "application/pdf",
                :length => File.size(serve_file.path)
              serve_file.close
            end
          end