blazy_blurry_placeholder-8.x-2.1/src/Plugin/Field/FieldFormatter/BlazyBlurryPlaceholderImageFormatter.php

<?php

namespace Drupal\blazy_blurry_placeholder\Plugin\Field\FieldFormatter;

use Drupal\Core\Field\FieldItemListInterface;
use Drupal\file\Entity\File;
use Drupal\image\Plugin\Field\FieldFormatter\ImageFormatter;

/**
 * Plugin implementation of the 'blazy_blurry_placeholder_image' formatter.
 *
 * @FieldFormatter(
 *   id = "blazy_blurry_placeholder_image",
 *   label = @Translation("Blazy Blurry Placeholder Image"),
 *   description = @Translation("Display a blurry placeholder of the image while lazy-loading it with bLazy."),
 *   field_types = {
 *     "image"
 *   }
 * )
 */
class BlazyBlurryPlaceholderImageFormatter extends ImageFormatter {

  public function viewElements(FieldItemListInterface $items, $langcode) {
    $elements = parent::viewElements($items, $langcode);

    foreach ($elements as &$element) {
      /** @var \Drupal\image\Plugin\Field\FieldType\ImageItem $image_item */
      $image_item = $element['#item'];

      $element = [
        '#theme' => 'blazy_blurry_placeholder_image',
        '#image' => File::load($image_item->get('target_id')->getValue()),
        '#image_style' => $element['#image_style'],
        '#title' => $image_item->get('title')->getValue(),
        '#alt' => $image_item->get('title')->getValue(),
        '#url' => $element['#url'],
        '#cache' => $element['#cache'],
      ];
    }

    $elements['#attached']['library'][] = 'blazy_blurry_placeholder/blazy';
    return $elements;
  }
}