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BackgroundImageManager.php in Background Image 2.x

Same filename and directory in other branches
  1. 8 src/BackgroundImageManager.php
  2. 2.0.x src/BackgroundImageManager.php

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src/BackgroundImageManager.php
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<?php

namespace Drupal\background_image;

use Drupal\Component\Utility\Color;
use Drupal\Component\Utility\Crypt;
use Drupal\Component\Utility\Html;
use Drupal\Component\Utility\NestedArray;
use Drupal\Core\Config\ConfigFactoryInterface;
use Drupal\Core\DependencyInjection\DependencySerializationTrait;
use Drupal\Core\Entity\EntityInterface;
use Drupal\Core\Entity\EntityRepositoryInterface;
use Drupal\Core\Entity\EntityTypeBundleInfoInterface;
use Drupal\Core\Entity\EntityTypeInterface;
use Drupal\Core\Entity\EntityTypeManagerInterface;
use Drupal\Core\Extension\ModuleHandlerInterface;
use Drupal\Core\File\Exception\FileException;
use Drupal\Core\File\FileSystemInterface;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Image\ImageFactory;
use Drupal\Core\Image\ImageInterface;
use Drupal\Core\Routing\ResettableStackedRouteMatchInterface;
use Drupal\Core\Routing\UrlGeneratorInterface;
use Drupal\Core\State\StateInterface;
use Drupal\Core\StringTranslation\StringTranslationTrait;
use Drupal\file\FileInterface;
use Drupal\imagemagick\Plugin\ImageToolkit\ImagemagickToolkit;
use Drupal\system\Plugin\ImageToolkit\GDToolkit;
use Drupal\views\ViewEntityInterface;
use Drupal\views\Views;
use Symfony\Component\DependencyInjection\ContainerAwareTrait;
use Symfony\Component\DependencyInjection\ContainerInterface;
class BackgroundImageManager implements BackgroundImageManagerInterface {
  use ContainerAwareTrait;
  use DependencySerializationTrait;
  use StringTranslationTrait;

  /**
   * @var \Drupal\background_image\BackgroundImageInterface[]
   */
  protected $backgroundImages;

  /**
   * @var \Drupal\Core\Config\ImmutableConfig
   */
  protected $config;

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

  /**
   * @var \Drupal\Core\Entity\EntityTypeBundleInfoInterface
   */
  protected $entityTypeBundleInfo;

  /**
   * @var \Drupal\Core\Entity\EntityTypeManagerInterface
   */
  protected $entityTypeManager;

  /**
   * @var \Drupal\Core\File\FileSystemInterface
   */
  protected $fileSystem;

  /**
   * @var \Drupal\Core\Image\ImageFactory
   */
  protected $imageFactory;

  /**
   * @var \Drupal\Core\Extension\ModuleHandlerInterface
   */
  protected $moduleHandler;

  /**
   * @var \Drupal\responsive_image\ResponsiveImageStyleInterface
   */
  protected $responsiveImageStyle;

  /**
   * @var \Drupal\Core\Routing\ResettableStackedRouteMatchInterface
   */
  protected $routeMatch;

  /**
   * @var \Drupal\Core\State\StateInterface
   */
  protected $state;

  /**
   * @var \Drupal\Core\Entity\EntityStorageInterface
   */
  protected $storage;

  /**
   * @var \Drupal\Core\Routing\UrlGeneratorInterface
   */
  protected $urlGenerator;

  /**
   * @var \Drupal\Core\Entity\EntityViewBuilderInterface
   */
  protected $viewBuilder;

  /**
   * BackgroundImageManager constructor.
   *
   * @param \Drupal\Core\Config\ConfigFactoryInterface
   *   The Config Factory service.
   * @param \Drupal\Core\Entity\EntityRepositoryInterface $entity_repository
   *   The entity repository.
   * @param \Drupal\Core\Entity\EntityTypeBundleInfoInterface $entity_type_bundle_info
   *   The Entity Type Bundle Info service.
   * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
   *   The Entity Type manager service.
   * @param \Drupal\Core\File\FileSystemInterface $file_system
   *   The File System service.
   * @param \Drupal\Core\Image\ImageFactory $image_factory
   *   The Image Factory service.
   * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
   *   The Module Handler service.
   * @param \Drupal\Core\Routing\ResettableStackedRouteMatchInterface $route_match
   *   The Route Match service.
   * @param \Drupal\Core\State\StateInterface $state
   *   The State service.
   * @param \Drupal\Core\Routing\UrlGeneratorInterface $url_generator
   *   The UrlGenerator service.
   *
   * @noinspection PhpDocMissingThrowsInspection
   */
  public function __construct(ConfigFactoryInterface $config_factory, EntityRepositoryInterface $entity_repository, EntityTypeBundleInfoInterface $entity_type_bundle_info, EntityTypeManagerInterface $entity_type_manager, FileSystemInterface $file_system, ImageFactory $image_factory, ModuleHandlerInterface $module_handler, ResettableStackedRouteMatchInterface $route_match, StateInterface $state, UrlGeneratorInterface $url_generator) {
    $this->config = $config_factory
      ->get('background_image.settings');
    $this->entityRepository = $entity_repository;
    $this->entityTypeBundleInfo = $entity_type_bundle_info;
    $this->entityTypeManager = $entity_type_manager;
    $this->fileSystem = $file_system;
    $this->imageFactory = $image_factory;
    $this->moduleHandler = $module_handler;
    $this->routeMatch = $route_match;
    $this->state = $state;
    $this->urlGenerator = $url_generator;

    /** @noinspection PhpUnhandledExceptionInspection */
    $this->storage = $this->entityTypeManager
      ->getStorage('background_image');
    $this->viewBuilder = $this->entityTypeManager
      ->getViewBuilder('background_image');
  }

  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container) {
    return new self($container
      ->get('config.factory'), $container
      ->get('entity.repository'), $container
      ->get('entity_type.bundle.info'), $container
      ->get('entity_type.manager'), $container
      ->get('file_system'), $container
      ->get('image.factory'), $container
      ->get('module_handler'), $container
      ->get('current_route_match'), $container
      ->get('state'), $container
      ->get('url_generator.non_bubbling'));
  }

  /**
   * {@inheritdoc}
   */
  public function alterEntityForm(array &$form, FormStateInterface $form_state) {

    // Check if inline_entity_form exists.
    $inline_entity_form = $this->moduleHandler
      ->moduleExists('inline_entity_form');

    // Only alter forms that have a "inline_entity_form_entity" set.
    // @see \Drupal\background_image\BackgroundImageManager::prepareForm

    /** @var \Drupal\Core\Entity\EntityInterface $entity */
    $entity = $form_state
      ->get('inline_entity_form_entity');
    if (!$inline_entity_form || !$entity) {
      return;
    }
    $group = $this
      ->getEntityConfig($entity, 'group');
    $require = $this
      ->getEntityConfig($entity, 'require');
    $background_image = $this
      ->getEntityBackgroundImage($entity);
    $form['background_image'] = [
      '#type' => 'details',
      '#theme_wrappers' => [
        'details__background_image',
      ],
      '#title' => $this
        ->t('Background Image'),
      '#open' => !$require && $group ? FALSE : TRUE,
      '#group' => $group,
      '#weight' => $group ? NULL : 100,
      '#tree' => TRUE,
    ];
    $form['background_image']['inline_entity_form'] = [
      '#theme_wrappers' => NULL,
      '#type' => 'inline_entity_form',
      '#entity_type' => 'background_image',
      '#langcode' => $entity
        ->language()
        ->getId(),
      '#default_value' => $background_image,
    ];
  }

  /**
   * {@inheritdoc}
   */
  public function cacheFlush() {
    $this->fileSystem
      ->scanDirectory('public://background_image/css', '/.*/', [
      'callback' => function ($uri) {
        try {

          // Silence any PHP errors, meant to be passive.
          @$this->fileSystem
            ->deleteRecursive($uri);
        } catch (FileException $e) {

          // Intentionally do nothing.
        }
      },
    ]);
  }

  /**
   * {@inheritdoc}
   */
  public function colorIsDark($hex = NULL) {
    if (!isset($hex)) {
      return FALSE;
    }
    $rgb = array_values(Color::hexToRgb($hex));
    return 0.213 * $rgb[0] + 0.715 * $rgb[1] + 0.07199999999999999 * $rgb[2] < 255 / 2;
  }

  /**
   * {@inheritdoc}
   */
  public function colorSampleFile(FileInterface $file = NULL, $default = NULL) {
    return isset($file) ? $this
      ->colorSampleImage($this->imageFactory
      ->get($file
      ->getFileUri()), $default) : $default;
  }

  /**
   * {@inheritdoc}
   */
  public function colorSampleImage(ImageInterface $image, $default = NULL) {

    // Immediately return if the image is not valid.
    if (!$image
      ->isValid()) {
      return $default;
    }

    // Retrieve the toolkit and use it, if valid.
    $toolkit = $image
      ->getToolkit();
    if ($toolkit instanceof GDToolkit) {
      return $this
        ->colorSampleGdImage($toolkit, $default);
    }
    else {
      if ($toolkit instanceof ImagemagickToolkit) {
        return $this
          ->colorSampleImagemagickImage($toolkit, $default);
      }
    }
    return $default;
  }

  /**
   * Determines the average color of an image using the GD toolkit.
   *
   * @param \Drupal\system\Plugin\ImageToolkit\GDToolkit $image
   *   A GD image toolkit object.
   * @param string $default
   *   A default lowercase simple color (HEX) representation to use if
   *   unable to sample the image.
   *
   * @return string
   *   An associative array with red, green, blue and alpha keys that contains
   *   the appropriate values for the specified color index.
   */
  protected function colorSampleGdImage(GDToolkit $image, $default = NULL) {
    if ($image
      ->apply('resize', [
      'width' => 1,
      'height' => 1,
    ]) && ($resource = $image
      ->getResource())) {
      return @Color::rgbToHex(array_slice(@imagecolorsforindex($resource, @imagecolorat($resource, 0, 0)), 0, 3)) ?: $default;
    }
    return $default;
  }

  /**
   * Determines the average color of an image using the Imagemagick toolkit.
   *
   * Due to how Imagemagick's toolkit works in Drupal, this doesn't actually
   * use any of the methods provided by the toolkit. This is because it
   * operates under the assumption that the output will be saved as an image.
   *
   * Since this is using an external binary and requires reading the text
   * output, the arguments must be constructed manually and the
   * ImagemagickExecManager service must be used directly.
   *
   * @see https://stackoverflow.com/a/25488429
   *
   * @param \Drupal\imagemagick\Plugin\ImageToolkit\ImagemagickToolkit $image
   *   An Imagemagick toolkit object.
   * @param string $default
   *   A default lowercase simple color (HEX) representation to use if
   *   unable to sample the image.
   *
   * @return string
   *   An associative array with red, green, blue and alpha keys that contains
   *   the appropriate values for the specified color index.
   *
   * @noinspection PhpDocMissingThrowsInspection
   */
  protected function colorSampleImagemagickImage(ImagemagickToolkit $image, $default = NULL) {

    // Note: this service cannot be injected because not everyone will have
    // this module installed. It can only be accessed here via runtime.

    /** @var \Drupal\imagemagick\ImagemagickExecManagerInterface $exec_manager */
    $exec_manager = \Drupal::service('imagemagick.exec_manager');

    /** @var \Drupal\imagemagick\ImagemagickExecArguments $arguments */
    $arguments = (new \ReflectionClass('\\Drupal\\imagemagick\\ImagemagickExecArguments'))
      ->newInstance($exec_manager)
      ->setSourceLocalPath($this->fileSystem
      ->realpath($image
      ->getSource()));
    $arguments
      ->add('-resize 1x1\\!')
      ->add('-format "%[fx:int(255*r+.5)],%[fx:int(255*g+.5)],%[fx:int(255*b+.5)]"')
      ->add('info:-');
    if ($exec_manager
      ->execute('convert', $arguments, $output, $error)) {
      return @Color::rgbToHex(explode(',', $output)) ?: $default;
    }
    return $default;
  }

  /**
   * {@inheritdoc}
   */
  public function getBackgroundImage($langcode = NULL, array $context = []) {
    $hash = Crypt::hashBase64(serialize(func_get_args()));
    if (!isset($this->backgroundImages[$hash])) {
      if ($entity = $this
        ->getEntityFromCurrentRoute()) {
        if ($entity instanceof EntityInterface && ($this->backgroundImages[$hash] = $this
          ->getEntityBackgroundImage($entity, $langcode, $context))) {
          return $this->backgroundImages[$hash];
        }
        else {
          if ($entity instanceof EntityInterface && ($this->backgroundImages[$hash] = $this
            ->getEntityBundleBackgroundImage($entity, $langcode, $context))) {
            return $this->backgroundImages[$hash];
          }
          else {
            if ($entity instanceof ViewEntityInterface && ($this->backgroundImages[$hash] = $this
              ->getViewBackgroundImage($entity, $langcode, $context))) {
              return $this->backgroundImages[$hash];
            }
          }
        }
      }
      $this->backgroundImages[$hash] = $this
        ->getGlobalBackgroundImage($langcode, $context) ?: FALSE;
    }
    return $this->backgroundImages[$hash];
  }

  /**
   * {@inheritdoc}
   */
  public function getBaseClass() {
    return Html::cleanCssIdentifier(preg_replace('/^(\\.|#)/', '', $this->config
      ->get('css.base_class') ?: 'background-image'));
  }

  /**
   * {@inheritdoc}
   */
  public function getCssMinifier() {

    // @todo this should be using $this->container, but it's not always set?
    return \Drupal::getContainer()
      ->get('advagg.css_minifier', ContainerInterface::NULL_ON_INVALID_REFERENCE);
  }

  /**
   * {@inheritdoc}
   */
  public function getDefaultSettings() {

    // Even though this is in the install config, it has the potential of
    // becoming removed. Due to the way BackgroundImageSettings works, the keys
    // must exist for values to be typecast properly.
    return NestedArray::mergeDeep([
      'blur' => [
        'type' => 2,
        'radius' => 50,
        'speed' => 1,
      ],
      'dark' => FALSE,
      'full_viewport' => FALSE,
      'preload' => [
        'background_color' => '#ffffff',
      ],
      'text' => [
        'format' => 'full_html',
        'value' => '',
      ],
    ], $this->config
      ->get('defaults') ?: []);
  }

  /**
   * {@inheritdoc}
   */
  public function getEnabledEntityTypes() {
    $supported = $this
      ->getSupportedEntityTypes();
    $enabled = [];
    foreach ($supported as $entity_type) {
      if (array_filter($this
        ->getEnabledEntityTypeBundles($entity_type))) {
        $enabled[$entity_type
          ->id()] = TRUE;
      }
    }
    return array_intersect_key($supported, $enabled);
  }

  /**
   * {@inheritdoc}
   */
  public function getEnabledEntityTypeBundles(EntityTypeInterface $entity_type) {
    $enabled = $this
      ->getEntityConfigArray($entity_type, NULL, 'enable');
    $bundles = $this
      ->getEntityTypeBundles($entity_type);
    if (empty($enabled[$entity_type
      ->id()]) || !$bundles) {
      return [];
    }
    return array_intersect_key($bundles, $enabled[$entity_type
      ->id()]);
  }

  /**
   * {@inheritdoc}
   */
  public function getEntityBackgroundImage(EntityInterface $entity, $langcode = NULL, array $context = []) {
    if ($this
      ->validEntity($entity)) {
      $entity_type = $entity
        ->getEntityType();
      $result = $this->storage
        ->loadByProperties([
        'type' => BackgroundImageInterface::TYPE_ENTITY,
        'target' => $entity_type
          ->id() . ':' . $entity
          ->uuid(),
      ]);
      if ($backgroundImage = reset($result)) {
        return $this->entityRepository
          ->getTranslationFromContext($backgroundImage, $langcode, $context);
      }
    }
    return NULL;
  }

  /**
   * {@inheritdoc}
   */
  public function getEntityBundleBackgroundImage(EntityInterface $entity, $langcode = NULL, array $context = []) {
    if ($bundle_entity_type = $entity
      ->getEntityType()
      ->getBundleEntityType()) {
      $result = $this->storage
        ->loadByProperties([
        'type' => BackgroundImageInterface::TYPE_ENTITY_BUNDLE,
        'target' => $entity
          ->getEntityTypeId() . ':' . $entity
          ->bundle(),
      ]);
      if ($backgroundImage = reset($result)) {
        return $this->entityRepository
          ->getTranslationFromContext($backgroundImage, $langcode, $context);
      }
    }
    return NULL;
  }

  /**
   * {@inheritdoc}
   */
  public function getEntityBundleLabel(EntityInterface $entity) {
    $bundles = $info = $this
      ->getEnabledEntityTypeBundles($entity
      ->getEntityType());
    if (isset($bundles[$entity
      ->bundle()]['label'])) {
      return $bundles[$entity
        ->bundle()]['label'];
    }
  }

  /**
   * {@inheritdoc}
   */
  public function getEntityConfig(EntityInterface $entity, $property) {
    $entity_type = $entity
      ->getEntityTypeId();
    $bundle = $entity
      ->bundle();
    $config = $this
      ->getEntityConfigArray($entity_type, $bundle, $property);
    return isset($config[$entity_type][$bundle]) ? $config[$entity_type][$bundle] : NULL;
  }

  /**
   * {@inheritdoc}
   */
  public function getEntityConfigArray($entity_type = NULL, $bundle = NULL, $property = NULL, $filter = TRUE) {
    if ($entity_type instanceof EntityInterface) {
      $entity_type = $entity_type
        ->getEntityTypeId();
    }
    else {
      if ($entity_type instanceof EntityTypeInterface) {
        $entity_type = $entity_type
          ->id();
      }
    }
    $entity_type = (string) $entity_type;

    // Return with the config if no property was specified.
    if (!$property) {
      $keys = [
        'entities',
      ];
      if ($entity_type) {
        $keys[] = $entity_type;
        if ($bundle) {
          $keys[] = (string) $bundle;
        }
      }
      $config = $this->config
        ->get(implode('.', $keys)) ?: [];
      return $filter ? array_filter($config) : $config;
    }

    // Return a nested property if a property was specified.
    $properties = [];
    foreach ($this->config
      ->get('entities') as $t => $bundles) {
      if ($entity_type && $entity_type !== $t) {
        continue;
      }
      foreach ($bundles as $b => $data) {
        if ($bundle && $bundle !== $b) {
          continue;
        }
        foreach ($data as $key => $value) {
          if ($key === $property) {
            $properties[$t][$b] = $value;
          }
        }
        if ($filter) {
          $properties[$t] = array_filter($properties[$t]);
        }
      }
      if ($filter) {
        $properties = array_filter($properties);
      }
    }
    return $properties;
  }

  /**
   * {@inheritdoc}
   */
  public function getEntityFromCurrentRoute($entity_type = NULL, $bundle = NULL) {

    /** @var \Drupal\Core\Entity\EntityInterface $entity */
    $entity = NULL;
    $parameters = $this->routeMatch
      ->getParameters();

    // If an entity type was passed, attempt to retrieve that object by name.
    if ($entity_type && $entity_type !== 'view' && ($parameter = $parameters
      ->get($entity_type)) && $this
      ->validEntity($parameter)) {
      $entity = $parameter;
    }
    else {
      if (($view_id = $parameters
        ->get('view_id')) && ($display_id = $parameters
        ->get('display_id')) && ($view = $this->entityTypeManager
        ->getStorage('view')
        ->load($view_id))) {

        /** @var \Drupal\views\ViewEntityInterface $view */
        $executable = $view
          ->getExecutable();
        $executable
          ->setDisplay($display_id);
        $entity = $view;
      }
      else {
        foreach ($parameters
          ->all() as $parameter) {
          if ($parameter instanceof EntityInterface && $this
            ->validEntity($parameter)) {
            $entity = $parameter;
            break;
          }
        }
      }
    }

    // If no bundle was provided, just return the entity.
    if (!isset($bundle)) {
      return $entity;
    }

    // Check if bundle matches.
    return $entity
      ->bundle() === $bundle ? $entity : NULL;
  }

  /**
   * {@inheritdoc}
   */
  public function getEntityTypeBundleEntityType(EntityTypeInterface $entity_type) {
    if ($bundle_entity_type = $entity_type
      ->getBundleEntityType()) {
      return $this->entityTypeManager
        ->getDefinition($bundle_entity_type);
    }
    return NULL;
  }

  /**
   * {@inheritdoc}
   */
  public function getEntityTypeBundles(EntityTypeInterface $entity_type) {
    return $this->entityTypeBundleInfo
      ->getBundleInfo($entity_type
      ->id());
  }

  /**
   * {@inheritdoc}
   */
  public function getFallbackImageStyle() {
    $image_style = $this->config
      ->get('image_style.fallback') ?: 'background_image_lg';
    if ($responsive_image_style = $this
      ->getResponsiveImageStyle()) {
      return $responsive_image_style
        ->getFallbackImageStyle() ?: $image_style;
    }
    return $image_style;
  }

  /**
   * {@inheritdoc}
   */
  public function getGlobalBackgroundImage($langcode = NULL, array $context = []) {
    $result = $this->storage
      ->loadByProperties([
      'type' => BackgroundImageInterface::TYPE_GLOBAL,
    ]);
    if ($backgroundImage = reset($result)) {
      return $this->entityRepository
        ->getTranslationFromContext($backgroundImage, $langcode, $context);
    }
    return NULL;
  }

  /**
   * {@inheritdoc}
   */
  public function getPreloadImageStyle() {
    return $this->config
      ->get('image_style.preload') ?: 'background_image_preload';
  }

  /**
   * {@inheritdoc}
   */
  public function getResponsiveImageStyle() {
    if (!isset($this->responsiveImageStyle)) {
      $this->responsiveImageStyle = $this->moduleHandler
        ->moduleExists('responsive_image') ? $this->entityTypeManager
        ->getStorage('responsive_image_style')
        ->load($this->config
        ->get('image_style.responsive') ?: 'background_image') : NULL;
    }
    return $this->responsiveImageStyle;
  }

  /**
   * {@inheritdoc}
   */
  public function getRetinaRules() {
    return $this->config
      ->get('css.retina_rules') ?: [];
  }

  /**
   * {@inheritdoc}
   */
  public function getSupportedEntityTypes() {
    static $entity_types;
    if (!isset($entity_types)) {
      $allowed_entity_types = [
        'view',
      ];
      foreach ($this->entityTypeManager
        ->getDefinitions() as $entity_type) {

        // Attempt to determine if the entity type can actually display a full page.
        $full_page = $entity_type
          ->hasViewBuilderClass() && $entity_type
          ->hasLinkTemplate('canonical') && $entity_type
          ->getLinkTemplate('canonical') !== $entity_type
          ->getLinkTemplate('edit-form');
        if (in_array($entity_type
          ->id(), $allowed_entity_types) || $full_page) {
          $entity_types[$entity_type
            ->id()] = $entity_type;
        }
      }
    }
    return $entity_types;
  }

  /**
   * {@inheritdoc}
   */
  public function getViewBackgroundImage(ViewEntityInterface $view, $langcode = NULL, array $context = []) {
    if ($this
      ->validView($view)) {
      $result = $this->storage
        ->loadByProperties([
        'type' => BackgroundImageInterface::TYPE_VIEW,
        'target' => "{$view->id()}:{$view->getExecutable()->current_display}",
      ]);
      if ($backgroundImage = reset($result)) {
        return $this->entityRepository
          ->getTranslationFromContext($backgroundImage, $langcode, $context);
      }
    }
    return NULL;
  }

  /**
   * {@inheritdoc}
   */
  public function getViewsPages() {
    static $views;
    if (!isset($views)) {
      $views = [];
      if (!$this->moduleHandler
        ->moduleExists('views')) {
        return $views;
      }
      foreach (Views::getEnabledViews() as $view_id => $view) {
        $displays = $view
          ->get('display');
        foreach ($displays as $display_id => $display) {
          if ($display['display_plugin'] === 'page') {
            $id = "{$view_id}:{$display_id}";
            if (isset($display['display_options']['menu']['title'])) {
              $views[$id] = $display['display_options']['menu']['title'] . " ({$id})";
            }
            else {
              $label = $view
                ->label();
              if (isset($display['display_title']) && $display['display_title'] !== 'Page') {
                $label .= ' - ' . $display['display_title'];
              }
              $views[$id] = $label . " ({$id})";
            }
          }
        }
      }
      ksort($views, SORT_NATURAL);
    }
    return $views;
  }

  /**
   * {@inheritdoc}
   */
  public function prepareEntityForm(EntityInterface $entity, $operation, FormStateInterface $form_state) {

    // Only continue if the necessary conditions are met. Views, while valid
    // entities, cannot be embedded. They must be handled in a special way.
    if ($entity
      ->bundle() === 'view' || !$this
      ->validEntity($entity) || !($operation === 'default' || $operation === 'add' || $operation === 'edit')) {
      return;
    }

    // Add the entity as a special key in the form state to indicate that
    // the form should be altered by Background Image.
    $form_state
      ->set('inline_entity_form_entity', $entity);
  }

  /**
   * {@inheritdoc}
   */
  public static function service() {
    return \Drupal::service('background_image.manager');
  }

  /**
   * {@inheritdoc}
   */
  public function useMinifiedCssUri() {
    return \Drupal::config('system.performance')
      ->get('css.preprocess') && $this
      ->getCssMinifier();
  }

  /**
   * {@inheritdoc}
   */
  public function validEntity(EntityInterface $entity) {

    // Check enabled entity bundles.
    if (!in_array($entity
      ->bundle(), array_keys($this
      ->getEnabledEntityTypeBundles($entity
      ->getEntityType())))) {
      return FALSE;
    }

    // Check enabled entity types.
    if (!in_array($entity
      ->getEntityTypeId(), array_keys($this
      ->getEnabledEntityTypes()))) {
      return FALSE;
    }
    return TRUE;
  }

  /**
   * {@inheritdoc}
   */
  public function validView(ViewEntityInterface $view) {

    // Check enabled entity bundles.
    if (!in_array("{$view->id()}:{$view->getExecutable()->current_display}", array_keys($this
      ->getViewsPages()))) {
      return FALSE;
    }
    return TRUE;
  }

  /**
   * {@inheritdoc}
   */
  public function view($background_image, $view_mode = 'full', $langcode = NULL) {
    return $this->viewBuilder
      ->view($background_image, $view_mode, $langcode);
  }

}

Classes