class FilterImageLazyLoad

Same name and namespace in other branches
  1. 10 core/modules/filter/src/Plugin/Filter/FilterImageLazyLoad.php \Drupal\filter\Plugin\Filter\FilterImageLazyLoad

Provides a filter to lazy load tracked images.

Attributes

#[Filter(id: "filter_image_lazy_load", title: new TranslatableMarkup("Lazy load images"), description: new TranslatableMarkup("Instruct browsers to lazy load images if dimensions are specified. Use in conjunction with and place after the 'Track images uploaded via a Text Editor' filter that adds image dimensions required for lazy loading. Results can be overridden by <code>&lt;img loading=&quot;eager&quot;&gt;</code>."), type: FilterInterface::TYPE_TRANSFORM_REVERSIBLE, weight: 15)]

Hierarchy

Expanded class hierarchy of FilterImageLazyLoad

1 file declares its use of FilterImageLazyLoad
FilterImageLazyLoadTest.php in core/modules/filter/tests/src/Unit/FilterImageLazyLoadTest.php

File

core/modules/filter/src/Plugin/Filter/FilterImageLazyLoad.php, line 17

Namespace

Drupal\filter\Plugin\Filter
View source
final class FilterImageLazyLoad extends FilterBase {
  
  /**
   * {@inheritdoc}
   */
  public function process($text, $langcode) : FilterProcessResult {
    $result = new FilterProcessResult($text);
    // If there are no images, return early.
    if (stripos($text, '<img ') === FALSE && stripos($text, 'data-entity-type="file"') === FALSE) {
      return $result;
    }
    return $result->setProcessedText($this->transformImages($text));
  }
  
  /**
   * Transform markup of images to include loading="lazy".
   *
   * @param string $text
   *   The markup to transform.
   *
   * @return string
   *   The transformed text with loading attribute added.
   */
  private function transformImages(string $text) : string {
    $dom = Html::load($text);
    $xpath = new \DOMXPath($dom);
    // Only set loading="lazy" if no existing loading attribute is specified and
    // dimensions are specified.
    foreach ($xpath->query('//img[not(@loading="eager") and @width and @height]') as $element) {
      assert($element instanceof \DOMElement);
      $element->setAttribute('loading', 'lazy');
    }
    return Html::serialize($dom);
  }

}

Members

Title Sort descending Deprecated Modifiers Object type Summary Overriden Title Overrides
DependencySerializationTrait::$_entityStorages protected property An array of entity type IDs keyed by the property name of their storages.
DependencySerializationTrait::$_serviceIds protected property An array of service IDs keyed by property name used for serialization.
DependencySerializationTrait::__sleep public function 3
DependencySerializationTrait::__wakeup public function 3
FilterBase::$provider public property The name of the provider that owns this filter.
FilterBase::$settings public property An associative array containing the configured settings of this filter.
FilterBase::$status public property A Boolean indicating whether this filter is enabled.
FilterBase::$weight public property The weight of this filter compared to others in a filter collection.
FilterBase::calculateDependencies public function Calculates dependencies for the configured plugin. Overrides DependentPluginInterface::calculateDependencies 1
FilterBase::defaultConfiguration public function Gets default configuration for this plugin. Overrides ConfigurableInterface::defaultConfiguration
FilterBase::getConfiguration public function Gets this plugin&#039;s configuration. Overrides ConfigurableInterface::getConfiguration
FilterBase::getDescription public function Returns the administrative description for this filter plugin. Overrides FilterInterface::getDescription
FilterBase::getHTMLRestrictions public function Returns HTML allowed by this filter&#039;s configuration. Overrides FilterInterface::getHTMLRestrictions 4
FilterBase::getLabel public function Returns the administrative label for this filter plugin. Overrides FilterInterface::getLabel
FilterBase::getType public function Returns the processing type of this filter plugin. Overrides FilterInterface::getType
FilterBase::prepare public function Prepares the text for processing. Overrides FilterInterface::prepare
FilterBase::setConfiguration public function Sets the configuration for this plugin instance. Overrides ConfigurableInterface::setConfiguration 1
FilterBase::settingsForm public function Generates a filter&#039;s settings form. Overrides FilterInterface::settingsForm 3
FilterBase::tips public function Generates a filter&#039;s tip. Overrides FilterInterface::tips 9
FilterBase::__construct public function Constructs a \Drupal\Component\Plugin\PluginBase object. Overrides PluginBase::__construct 4
FilterImageLazyLoad::process public function Performs the filter processing. Overrides FilterInterface::process
FilterImageLazyLoad::transformImages private function Transform markup of images to include loading=&quot;lazy&quot;.
FilterInterface::TYPE_HTML_RESTRICTOR constant HTML tag and attribute restricting filters to prevent XSS attacks.
FilterInterface::TYPE_MARKUP_LANGUAGE constant Non-HTML markup language filters that generate HTML.
FilterInterface::TYPE_TRANSFORM_IRREVERSIBLE constant Irreversible transformation filters.
FilterInterface::TYPE_TRANSFORM_REVERSIBLE constant Reversible transformation filters.
MessengerTrait::$messenger protected property The messenger. 25
MessengerTrait::messenger public function Gets the messenger. 25
MessengerTrait::setMessenger public function Sets the messenger.
PluginBase::$configuration protected property Configuration information passed into the plugin. 1
PluginBase::$pluginDefinition protected property The plugin implementation definition. 1
PluginBase::$pluginId protected property The plugin ID.
PluginBase::DERIVATIVE_SEPARATOR constant A string which is used to separate base plugin IDs from the derivative ID.
PluginBase::getBaseId public function Gets the base_plugin_id of the plugin instance. Overrides DerivativeInspectionInterface::getBaseId
PluginBase::getDerivativeId public function Gets the derivative_id of the plugin instance. Overrides DerivativeInspectionInterface::getDerivativeId
PluginBase::getPluginDefinition public function Gets the definition of the plugin implementation. Overrides PluginInspectionInterface::getPluginDefinition 2
PluginBase::getPluginId public function Gets the plugin ID of the plugin instance. Overrides PluginInspectionInterface::getPluginId
PluginBase::isConfigurable Deprecated public function Determines if the plugin is configurable.
StringTranslationTrait::$stringTranslation protected property The string translation service. 3
StringTranslationTrait::formatPlural protected function Formats a string containing a count of items.
StringTranslationTrait::getNumberOfPlurals protected function Returns the number of plurals supported by a given language.
StringTranslationTrait::getStringTranslation protected function Gets the string translation service.
StringTranslationTrait::setStringTranslation public function Sets the string translation service to use. 2
StringTranslationTrait::t protected function Translates a string to the current language or to a given language. 1

Buggy or inaccurate documentation? Please file an issue. Need support? Need help programming? Connect with the Drupal community.