A custom Drupal 8 filter plugin to use an image style for image embedss custom Drupal 8 filter plugin to use an image style for image embeds. A custom Drupal 8 filter plugin to use an image style for image embeds.

EditorImageStyle.php

<?php

namespace Drupal\ppdx_editor\Plugin\Filter;

use Drupal\Component\Utility\Html;
use Drupal\Core\Entity\EntityRepositoryInterface;
use Drupal\Core\Image\ImageFactory;
use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
use Drupal\file\FileInterface;
use Drupal\filter\FilterProcessResult;
use Drupal\filter\Plugin\FilterBase;
use Drupal\image\Entity\ImageStyle;
use Symfony\Component\DependencyInjection\ContainerInterface;

/**
 * Use an image style for uploads.
 *
 * Based on \Drupal\editor\Plugin\Filter\EditorFileReference
 *
 * @Filter(
 *   id = "ppdx_image_style",
 *   title = @Translation("Use an image style for uploads"),
 *   description = @Translation("Uses a hard-coded image style for uploads."),
 *   type = Drupal\filter\Plugin\FilterInterface::TYPE_TRANSFORM_REVERSIBLE
 * )
 */
class EditorImageStyle extends FilterBase implements ContainerFactoryPluginInterface {

  /**
   * The entity repository.
   *
   * @var \Drupal\Core\Entity\EntityRepositoryInterface
   */
  protected $entityRepository;

  /**
   * The image factory.
   *
   * @var \Drupal\Core\Image\ImageFactory
   */
  protected $imageFactory;

  /**
   * Constructs an EditorImageStyle object.
   *
   * @param array $configuration
   *   A configuration array containing information about the plugin instance.
   * @param string $plugin_id
   *   The plugin_id for the plugin instance.
   * @param mixed $plugin_definition
   *   The plugin implementation definition.
   * @param \Drupal\Core\Entity\EntityRepositoryInterface $entity_repository
   *   The entity repository.
   * @param \Drupal\Core\Image\ImageFactory $image_factory
   *   The image factory.
   */
  public function __construct(array $configuration, $plugin_id, $plugin_definition, EntityRepositoryInterface $entity_repository, ImageFactory $image_factory) {
    $this->entityRepository = $entity_repository;
    $this->imageFactory = $image_factory;
    parent::__construct($configuration, $plugin_id, $plugin_definition);
  }

  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
    return new static(
      $configuration,
      $plugin_id,
      $plugin_definition,
      $container->get('entity.repository'),
      $container->get('image.factory')
    );
  }

  /**
   * {@inheritdoc}
   */
  public function process($text, $langcode) {
    $result = new FilterProcessResult($text);
    // Replace "review_image" with the name of your image style.
    $style = ImageStyle::load('review_image');
    $used_style = FALSE;

    if (stristr($text, 'data-entity-type="file"') !== FALSE) {
      $dom = Html::load($text);
      $xpath = new \DOMXPath($dom);
      foreach ($xpath->query('//*[@data-entity-type="file" and @data-entity-uuid]') as $node) {
        $uuid = $node->getAttribute('data-entity-uuid');

        if ($node->hasAttribute('src')) {
          $file = $this->entityRepository->loadEntityByUuid('file', $uuid);
          if ($file instanceof FileInterface) {
            $uri = $file->getFileUri();
            $image = $this->imageFactory->get($uri);
            if ($image->isValid() && $style->supportsUri($uri)) {
              $dimensions = [
                'width' => $image->getWidth(),
                'height' => $image->getHeight(),
              ];
              $style->transformDimensions($dimensions, $uri);
              $node->setAttribute('src', $style->buildUrl($uri));
              $node->setAttribute('width', $dimensions['width']);
              $node->setAttribute('height', $dimensions['height']);
              $used_style = TRUE;
            }
          }
        }
      }
      $result->setProcessedText(Html::serialize($dom));
    }

    if ($used_style) {
      $result->addCacheTags($style->getCacheTags());
      $result->addCacheContexts($style->getCacheContexts());
    }

    return $result;
  }

}