def safe_zone(opts = {})
      safe_defaults = {
        margin: '0.25in',
        radius: '0.125in',
        stroke_color: :blue,
        fill_color: '#0000',
        stroke_width: 1.0,
        dash: '3 3',
      }
      new_opts = safe_defaults.merge(opts)
      margin = Args::UnitConversion.parse new_opts[:margin]
      new_opts[:x] = margin
      new_opts[:y] = margin
      new_opts[:width] = width - (2 * margin)
      new_opts[:height] = height - (2 * margin)
      rect new_opts
    end
def safe_zone(opts = {})
      safe_defaults = {
        margin: '0.25in',
        radius: '0.125in',
        stroke_color: :blue,
        fill_color: '#0000',
        stroke_width: 1.0,
        dash: '3 3',
      }
      new_opts = safe_defaults.merge(opts)
      margin = Args::UnitConversion.parse new_opts[:margin]
      new_opts[:x] = margin
      new_opts[:y] = margin
      new_opts[:width] = width - (2 * margin)
      new_opts[:height] = height - (2 * margin)
      rect new_opts
    end
DSL method. See http://squib.readthedocs.io