engelsystem/includes/helper/graph_helper.php

<?php

/**
 * Renders a bargraph
 * @param string $key keyname of the x-axis
 * @param array $row_names keynames for the data rows
 * @param unknown $colors colors for the data rows
 * @param unknown $data the data
 */
function bargraph($dom_id, $key, $row_names, $colors, $data)
{
    $labels = [];
    foreach ($data as $dataset) {
        $labels[] = $dataset[$key];
    }
  
    $datasets = [];
    foreach ($row_names as $row_key => $name) {
        $values = [];
        foreach ($data as $dataset) {
            $values[] = $dataset[$row_key];
        }
        $datasets[] = [
        'label' => $name,
        'fillColor' => $colors[$row_key],
        'data' => $values
    ];
    }
  
    return '<canvas id="' . $dom_id . '" style="width: 100%; height: 300px;"></canvas>
      <script type="text/javascript">
      $(function(){
        var ctx = $("#' . $dom_id . '").get(0).getContext("2d");
        var chart = new Chart(ctx).Bar(' . json_encode([
      'labels' => $labels,
      'datasets' => $datasets
  ]) . ');
      });
      </script>';
}