let repositionHead = Math.min(margin.head, options.widthOfOneDigit * 0.5) + bump
          + (orient == HORIZONTAL ? 1 : 0) * d3.max(range)
          - (orient == HORIZONTAL ? 0 : 1) * d3.min(range)
          + (orient == HORIZONTAL ? -1 : 1) * scale(d)
          - (dimension == "x") * options.formatter(d).length * options.widthOfOneDigit / 2