title: PHPExcel Piechart labels and legends
body: <p>I have a problem with the library PHPExcel (1.7.7): When I want to create a piechart, labels and legends are not displayed. However, with other graphics, I do not have that problem. Do you have any a solution?</p>
  
  <p>Thanks.</p>
  
  <p>Here is the code used:</p>
  
  <pre><code>$categories = array(
  new PHPExcel_Chart_DataSeriesValues('String', 'RECAPITULATIF!$B$6:$B$8', null, 3),
      );
  
  $values = array(
  new PHPExcel_Chart_DataSeriesValues('Number',  'RECAPITULATIF!$F$6:$F$8', null, 3),
  );
  
  $series = new PHPExcel_Chart_DataSeries(
      PHPExcel_Chart_DataSeries::TYPE_PIECHART,       // plotType
      PHPExcel_Chart_DataSeries::GROUPING_CLUSTERED,  // plotGrouping
      array(0),                                       // plotOrder
      null,                                           // plotLabel
      $categories,                                    // plotCategory
      $values                                         // plotValues
      );
  
  $plotarea = new PHPExcel_Chart_PlotArea(null, array($series));
  $title = new PHPExcel_Chart_Title('Pie chart');
  $legend = new PHPExcel_Chart_Legend(PHPExcel_Chart_Legend::POSITION_RIGHT, null, false);
  
  $chart = new PHPExcel_Chart(
      'chart2',                                       // name
      $title,                                         // title
      $legend,                                        // legend
      $plotarea,                                      // plotArea
      true,                                           // plotVisibleOnly
      0,                                              // displayBlanksAs
      null,                                           // xAxisLabel
      null                                            // yAxisLabel
      );
  </code></pre>