    # File lib/prawn/font.rb, line 30
        def font(name=nil, options={})
          return @font || font("Helvetica") if name.nil?

          raise Errors::NotOnPage unless @current_page
          new_font = find_font(name, options)

          if block_given?
            save_font do
              set_font(new_font, options[:size])
              yield
            end
          else
            set_font(new_font, options[:size])
          end

          @font
        end