def _GetGridParams(self, chart):
    """Collect params related to grid lines."""
    x = 0
    y = 0
    if chart.bottom.grid_spacing:
      # min/max must be set for this to make sense.
      assert(chart.bottom.min is not None)
      assert(chart.bottom.max is not None)
      total = float(chart.bottom.max - chart.bottom.min)
      x = 100 * chart.bottom.grid_spacing / total
    if chart.left.grid_spacing:
      # min/max must be set for this to make sense.
      assert(chart.left.min is not None)
      assert(chart.left.max is not None)
      total = float(chart.left.max - chart.left.min)
      y = 100 * chart.left.grid_spacing / total
    if x or y:
      return dict(grid = '%.3g,%.3g,1,0' % (x, y))
    return {}
Collect params related to grid lines.
mapreduce/lib/graphy/backends/google_chart_api/encoders.py