# File lib/nanoc/cli/commands/compile.rb, line 229
    def start_filter_progress(rep, filter_name)
      # Only show progress on terminals
      return if !$stdout.tty?

      @progress_thread = Thread.new do
        delay = 1.0
        step  = 0

        text = "  running #{filter_name} filter… "

        loop do
          if Thread.current[:stopped]
            # Clear
            if delay < 0.1
              $stdout.print ' ' * (text.length + 3) + "\r"
            end

            break
          end

          # Show progress
          if delay < 0.1
            $stdout.print text + %w( | / - \\ )[step] + "\r"
            step = (step + 1) % 4
          end

          sleep 0.1
          delay -= 0.1
        end

      end
    end