     if @options.orientation == 'horizontal'
       d3.scale.ordinal()
         .domain(Epoch.Util.domain(@data))
-        .rangeRoundBands([0, @innerWidth()], .1)
+        .rangeRoundBands([0, @innerWidth()], @options.padding.group)
     else
       extent = @extent((d) -> d.y)
       extent[0] = Math.min(0, extent[0])

    else
      d3.scale.ordinal()
        .domain(Epoch.Util.domain(@data))
        .rangeRoundBands([0, @innerHeight()], .1)

  # @return [Function] The x scale used to render the vertical bar chart.
  y1: (y0) ->
    d3.scale.ordinal()
      .domain((layer.category for layer in @data))
      .rangeRoundBands([0, y0.rangeBand()], .08)

  # Remaps the bar chart data into a form that is easier to display.
  # @return [Array] The reorganized data.

  defaults = 
    style: 'grouped'
    orientation: 'horizontal'
    padding:
      bar: 0.08
      group: 0.1

  vertical_specific =
    tickFormats:
      top: Epoch.Formats.si
      bottom: Epoch.Formats.si
      left: Epoch.Formats.regular
      right: Epoch.Formats.regular

  vertical_defaults = Epoch.Util.defaults(vertical_specific, defaults)

  constructor: (@options={}) ->
    if @options.orientation == 'vertical'
