code: function makeXcord(chart, fullWidth, t, spacing, markerRadius) {
      if (chart.drawChart) {
            return Math.min(fullWidth * t, spacing + markerRadius);
          } else if (chart.stretchChart) {
            return t * (spacing + markerRadius);
          } else {
            return spacing + markerRadius;
          }
    }
docs: Common function used by line/spline/area charts to compute
  the next X coordinate when generating the chart SVG path.