/**
* Generates JSON graph data and returns it.
*
* @param DataTable|DataTable\Map $dataTable
* @return string
*/
public function generate($dataTable)
{
$visualization = new Chart();
if ($dataTable->getRowsCount() > 0) {
// if addTotalRow was called in GenerateGraphHTML, add a row containing totals of
// different metrics
if ($this->properties['add_total_row']) {
$dataTable->queueFilter('AddSummaryRow', Piwik::translate('General_Total'));
}
$dataTable->applyQueuedFilters();
$this->initChartObjectData($dataTable, $visualization);
}
return $visualization->render();
}
/**
* @param DataTable\Map $dataTableMap
* @param string $columnToPlot
*
* @return array
* @throws \Exception
*/
protected function getValuesFromDataTableMap($dataTableMap, $columnToPlot)
{
$dataTableMap->applyQueuedFilters();
$values = array();
foreach ($dataTableMap->getDataTables() as $table) {
if ($table->getRowsCount() > 1) {
throw new Exception("Expecting only one row per DataTable");
}
$value = 0;
$onlyRow = $table->getFirstRow();
if (false !== $onlyRow) {
if (!empty($columnToPlot)) {
$value = $onlyRow->getColumn($columnToPlot);
} else {
$columns = $onlyRow->getColumns();
$value = current($columns);
}
}
$values[] = $value;
}
return $values;
}
