function __construct($values, $labels)
 {
     parent::__construct();
     $this->values = $values;
     $this->labels = $labels;
     $this->oChart = $this->buildChart();
 }
 protected function setUpGraph()
 {
     parent::setUpGraph();
     $aDataSets = $this->getDataSets();
     // if no data, or only one data point, we don't display the graph
     if (count($this->xLabels) <= 1) {
         return false;
     }
     $chart = $this->getGraph();
     //set up the axes
     $y_axis = $this->createYAxis();
     $y_axis->set_range(max(0, $this->getMinYValue() - 1), $this->getMaxYValue() + 1);
     $y_axis->set_steps(ceil($this->getMaxYValue() / 4));
     $y_axis->set_label_text("#val#" . $this->yUnit);
     //y_axis legend
     $y_legend = new y_legend('Viewers');
     $y_legend->set_style('color: #515151; font-size: 12px;');
     $chart->set_y_legend($y_legend);
     $x_axis = $this->createXAxis();
     $x_values = $this->xLabels;
     $xSteps = 5;
     if (count($x_values) < $xSteps) {
         $xSteps = count($x_values);
     } else {
         // hack around the set_steps that doesn't seem to work for X axis
         foreach ($x_values as $i => &$xValue) {
             if ($i % $xSteps != 0) {
                 $xValue = '';
             }
         }
     }
     $x_axis->set_steps($xSteps);
     $x_labels = new x_axis_labels();
     $x_labels->set_labels($x_values);
     // Add the X Axis Labels to the X Axis
     $x_axis->set_labels($x_labels);
     $chart->add_y_axis($y_axis);
     $chart->x_axis = $x_axis;
     $oColorHelper = new Graph_DataSetColorsHelper();
     foreach ($aDataSets as $aDataSet) {
         $values = $aDataSet['values'];
         $name = $aDataSet['name'];
         $aColors = $oColorHelper->getNextColors();
         $dotValues = $this->buildDotValues($aColors['line'], $values, $name);
         $area = $this->createArea($aColors['line'], $aColors['fill']);
         $area->set_fill_alpha("0.1");
         $area->set_values($dotValues);
         $area->set_text($name);
         // add the area object to the chart:
         $chart->add_element($area);
     }
     return $chart;
 }