    # File lib/prawn/font/afm.rb, line 23
          def self.metrics_path
            if m = ENV['METRICS']
              @metrics_path ||= m.split(':')
            else
              @metrics_path ||= [
                ".", "/usr/lib/afm",
                "/usr/local/lib/afm",
                "/usr/openwin/lib/fonts/afm/",
                 Prawn::BASEDIR+'/data/fonts/']
            end
          end