Canvas.php in Flot 8

Namespace

Drupal\flot_examples\Controller

File

flot_examples/src/Controller/Canvas.php

<?php

namespace Drupal\flot_examples\Controller;

use Drupal\Core\Controller\ControllerBase;

/**
 * Display a chart in canvas mode.
 */
class Canvas extends ControllerBase {

  /**
   * Zooming.
   */
  public function content() {
    $oilprices = $this::getData('OilData.txt');
    $exchangerates = $this::getData('ExchangeData.txt');
    $data[] = [
      'data' => $oilprices,
      'label' => "Oil price (\$)",
    ];
    $data[] = [
      'data' => $exchangerates,
      'label' => "USD/EUR exchange rate",
      'yaxis' => 2,
    ];
    $options = [
      'canvas' => TRUE,
      'xaxes' => [
        [
          'mode' => "time",
        ],
      ],
      'yaxes' => [
        [
          'min' => 0,
        ],
        [
          'position' => "right",
          'alignTicksWithAxis' => 1,
          'tickFormatter' => 'function',
        ],
      ],
      'legend' => [
        'position' => "sw",
      ],
    ];
    $text = [];
    $text[] = $this
      ->t('This example uses the same dataset (raw oil price in US $/barrel of crude oil vs. the exchange rate from US $ to €) as the multiple-axes example, but uses the canvas plugin to render axis tick labels using canvas text.');
    $text[] = [
      [
        '#type' => 'checkbox',
        '#title' => $this
          ->t('Enable canvas text'),
      ],
    ];
    $output[] = [
      '#type' => 'flot',
      '#theme' => 'flot_examples',
      '#data' => $data,
      '#options' => $options,
      '#text' => $text,
      '#attached' => [
        'library' => [
          'flot_examples/canvas',
        ],
      ],
    ];
    return $output;
  }

  /**
   * Fetch the raw data from the data file.
   */
  private function getData($filename) {
    $file_path = DRUPAL_ROOT . '/' . drupal_get_path('module', 'flot_examples') . '/src/Controller/' . $filename;
    $file = fopen($file_path, "r") or die("Unable to open file: {$file_path}");
    $data = [];
    while (!feof($file)) {
      $line = fgets($file);
      $values = explode(', ', $line);
      if (count($values) == 2) {
        $data[] = [
          $values[0],
          $values[1],
        ];
      }
    }
    fclose($file);
    return $data;
  }

}

Classes

Name	Description
Canvas	Display a chart in canvas mode.