class ImageUrlFormatter

class ImageUrlFormatter extends ImageFormatterBase {
    
    /**
     * The image style entity storage.
     *
     * @var \Drupal\image\ImageStyleStorageInterface
     */
    protected $imageStyleStorage;
    
    /**
     * The current user.
     *
     * @var \Drupal\Core\Session\AccountInterface
     */
    protected $currentUser;
    
    /**
     * Constructs an ImageFormatter object.
     *
     * @param string $plugin_id
     *   The plugin_id for the formatter.
     * @param mixed $plugin_definition
     *   The plugin implementation definition.
     * @param \Drupal\Core\Field\FieldDefinitionInterface $field_definition
     *   The definition of the field to which the formatter is associated.
     * @param array $settings
     *   The formatter settings.
     * @param string $label
     *   The formatter label display setting.
     * @param string $view_mode
     *   The view mode.
     * @param array $third_party_settings
     *   Any third party settings.
     * @param \Drupal\Core\Entity\EntityStorageInterface $image_style_storage
     *   The image style storage.
     * @param \Drupal\Core\Session\AccountInterface $current_user
     *   The current user.
     */
    public function __construct($plugin_id, $plugin_definition, FieldDefinitionInterface $field_definition, array $settings, $label, $view_mode, array $third_party_settings, EntityStorageInterface $image_style_storage, AccountInterface $current_user) {
        parent::__construct($plugin_id, $plugin_definition, $field_definition, $settings, $label, $view_mode, $third_party_settings);
        $this->imageStyleStorage = $image_style_storage;
        $this->currentUser = $current_user;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
        return new static($plugin_id, $plugin_definition, $configuration['field_definition'], $configuration['settings'], $configuration['label'], $configuration['view_mode'], $configuration['third_party_settings'], $container->get('entity_type.manager')
            ->getStorage('image_style'), $container->get('current_user'));
    }
    
    /**
     * {@inheritdoc}
     */
    public static function defaultSettings() {
        return [
            'image_style' => '',
        ];
    }
    
    /**
     * {@inheritdoc}
     */
    public function settingsForm(array $form, FormStateInterface $form_state) {
        $element = parent::settingsForm($form, $form_state);
        unset($element['image_link'], $element['image_loading']);
        $image_styles = image_style_options(FALSE);
        $description_link = Link::fromTextAndUrl($this->t('Configure Image Styles'), Url::fromRoute('entity.image_style.collection'));
        $element['image_style'] = [
            '#title' => $this->t('Image style'),
            '#type' => 'select',
            '#default_value' => $this->getSetting('image_style'),
            '#empty_option' => $this->t('None (original image)'),
            '#options' => $image_styles,
            '#description' => $description_link->toRenderable() + [
                '#access' => $this->currentUser
                    ->hasPermission('administer image styles'),
            ],
        ];
        return $element;
    }
    
    /**
     * {@inheritdoc}
     */
    public function settingsSummary() {
        $summary = [];
        $image_styles = image_style_options(FALSE);
        // Unset possible 'No defined styles' option.
        unset($image_styles['']);
        // Styles could be lost because of enabled/disabled modules that defines
        // their styles in code.
        $image_style_setting = $this->getSetting('image_style');
        if (isset($image_styles[$image_style_setting])) {
            $summary[] = $this->t('Image style: @style', [
                '@style' => $image_styles[$image_style_setting],
            ]);
        }
        else {
            $summary[] = $this->t('Original image');
        }
        return array_merge($summary, parent::settingsSummary());
    }
    
    /**
     * {@inheritdoc}
     */
    public function viewElements(FieldItemListInterface $items, $langcode) {
        $elements = [];
        
        /** @var \Drupal\Core\Field\EntityReferenceFieldItemListInterface $items */
        if (empty($images = $this->getEntitiesToView($items, $langcode))) {
            // Early opt-out if the field is empty.
            return $elements;
        }
        
        /** @var \Drupal\image\ImageStyleInterface $image_style */
        $image_style = $this->imageStyleStorage
            ->load($this->getSetting('image_style'));
        
        /** @var \Drupal\Core\File\FileUrlGeneratorInterface $file_url_generator */
        $file_url_generator = \Drupal::service('file_url_generator');
        
        /** @var \Drupal\file\FileInterface[] $images */
        foreach ($images as $delta => $image) {
            $image_uri = $image->getFileUri();
            $url = $image_style ? $file_url_generator->transformRelative($image_style->buildUrl($image_uri)) : $file_url_generator->generateString($image_uri);
            // Add cacheability metadata from the image and image style.
            $cacheability = CacheableMetadata::createFromObject($image);
            if ($image_style) {
                $cacheability->addCacheableDependency(CacheableMetadata::createFromObject($image_style));
            }
            $elements[$delta] = [
                '#markup' => $url,
            ];
            $cacheability->applyTo($elements[$delta]);
        }
        return $elements;
    }

}