    # File lib/compass/grid_builder.rb, line 85
        def generate!
          (0...@height-1).each do |line|
            @data[line] = Array.new(@width){|x| x < @column_width ? [0xe8, 0xef, 0xfb] : [0xff,0xff,0xff] }
          end

          if File.exists?(filename)
            if options[:force]
              overwrite = true
            else
              msg = "#{filename} already exists. Overwrite with --force."
              raise Compass::FilesystemConflict.new(msg)
            end
          end
          directory File.dirname(filename)
          write_file(filename, self.to_blob, options, true)
        end