consumer_image_styles-8.x-3.0/consumer_image_styles.module

<?php

/**
 * @file
 * Module implementation file.
 */

use Drupal\Core\Entity\EntityTypeInterface;
use Drupal\Core\Field\BaseFieldDefinition;
use Drupal\Core\Field\FieldStorageDefinitionInterface;
use Drupal\Core\StringTranslation\TranslatableMarkup;

/**
 * Implements hook_entity_base_field_info().
 */
function consumer_image_styles_entity_base_field_info(EntityTypeInterface $entity_type) {
  $fields = [];
  if ($entity_type->id() == 'consumer') {
    $fields['image_styles'] = BaseFieldDefinition::create('entity_reference')
      ->setLabel(new TranslatableMarkup('Image Styles'))
      ->setDescription(new TranslatableMarkup('Image styles this consumer will need. All images will provide all the variants selected here.'))
      ->setRevisionable(TRUE)
      ->setSetting('target_type', 'image_style')
      ->setSetting('handler', 'default')
      ->setCardinality(FieldStorageDefinitionInterface::CARDINALITY_UNLIMITED)
      ->setTranslatable(FALSE)
      ->setDisplayOptions('view', [
        'label' => 'inline',
        'type' => 'entity_reference_label',
        'weight' => 5,
      ])
      ->setDisplayOptions('form', [
        'type' => 'options_buttons',
        'weight' => 5,
      ]);
  }
  return $fields;
}

/**
 * Implements hook_consumers_list_alter().
 */
function consumer_image_styles_consumers_list_alter(&$data, $context) {
  if ($context['type'] === 'header') {
    $data['image_styles'] = t('Image Styles');
  }
  elseif ($context['type'] === 'row') {
    $entity = $context['entity'];
    $data['image_styles'] = [
      'data' => ['#theme' => 'item_list', '#items' => []],
    ];

    // Add all image style labels.
    /** @var \Drupal\consumer_image_styles\ImageStylesProvider $image_styles_provider */
    $image_styles_provider = \Drupal::service('consumer_image_styles.image_styles_provider');
    $image_styles = $image_styles_provider->loadStyles($entity);
    foreach ($image_styles as $image_style) {
      $data['image_styles']['data']['#items'][] = $image_style->label();
    }
  }
}