d < this.seriesSet.length; d++) {
      context.save();
      var timeSeries = this.seriesSet[d].timeSeries,
          dataSet = timeSeries.data,
          seriesOptions = this.seriesSet[d].options;

      // Delete old data that's moved off the left of the chart.
      timeSeries.dropOldData(oldestValidTime, chartOptions.maxDataSetLength);

      // Set style for this dataSet.
      context.lineWidth = seriesOptions.lineWidth;
      context.strokeStyle = seriesOptions.strokeStyle;
      // Draw the line...