class GaussianBlurImageEffect in Image Effects 8

Blur image using the Gaussian function.

Plugin annotation

@ImageEffect(
  id = "image_effects_gaussian_blur",
  label = @Translation("Gaussian blur"),
  description = @Translation("Blur the image with a Gaussian operator.")
)

Hierarchy

• class \Drupal\Component\Plugin\PluginBase implements DerivativeInspectionInterface, PluginInspectionInterface
  • class \Drupal\Core\Plugin\PluginBase uses DependencySerializationTrait, MessengerTrait, StringTranslationTrait
    • class \Drupal\image\ImageEffectBase implements ContainerFactoryPluginInterface, ImageEffectInterface
      • class \Drupal\image\ConfigurableImageEffectBase implements ConfigurableImageEffectInterface
        • class \Drupal\image_effects\Plugin\ImageEffect\GaussianBlurImageEffect

File

src/Plugin/ImageEffect/GaussianBlurImageEffect.php, line 18

Namespace

Drupal\image_effects\Plugin\ImageEffect

class GaussianBlurImageEffect extends ConfigurableImageEffectBase {

  /**
   * {@inheritdoc}
   */
  public function defaultConfiguration() {
    return [
      'radius' => 3,
      'sigma' => NULL,
    ] + parent::defaultConfiguration();
  }

  /**
   * {@inheritdoc}
   */
  public function getSummary() {
    return [
      '#theme' => 'image_effects_gaussian_blur_summary',
      '#data' => $this->configuration,
    ] + parent::getSummary();
  }

  /**
   * {@inheritdoc}
   */
  public function buildConfigurationForm(array $form, FormStateInterface $form_state) {
    $form['info'] = [
      '#type' => 'details',
      '#title' => $this
        ->t('Information'),
    ];
    $form['info']['help'] = [
      '#markup' => $this
        ->t("A Gaussian blur is generated by replacing each pixel's color values with the average of the surrounding pixels' colors. This region is a circle whose radius is given by the 'radius' argument. Thus, a larger 'radius' will yield a blurrier image. This average is not a simple mean of the values. Instead, values are weighted using the Gaussian function (roughly a bell curve centered around the destination pixel) giving it much more influence on the result than its neighbours. Thus, a fatter curve will give the center pixel more weight and make the image less  blurry; lower 'sigma' values will yield flatter curves."),
    ];
    $form['radius'] = [
      '#type' => 'number',
      '#title' => $this
        ->t('Radius'),
      '#description' => $this
        ->t('The radius of the blur, in pixels. <strong>The larger the radius, the slower the operation is.</strong> However, too small radius can lead to undesired aliasing effects.'),
      '#default_value' => $this->configuration['radius'],
      '#field_suffix' => $this
        ->t('px'),
      '#required' => TRUE,
      '#size' => 3,
      '#min' => 1,
      '#max' => 15,
    ];
    $form['sigma'] = [
      '#type' => 'number',
      '#title' => $this
        ->t('Sigma'),
      '#description' => $this
        ->t("Represents the 'fatness' of the Gaussian curve. Lower values mean less blurry image. Leave blank to use toolkit's default. As a guideline, 2/3 of the radius is a good starting point."),
      '#default_value' => $this->configuration['sigma'],
      '#required' => FALSE,
      '#size' => 5,
      '#min' => 0.1,
      '#max' => 15,
      '#step' => 0.1,
    ];
    return $form;
  }

  /**
   * {@inheritdoc}
   */
  public function validateConfigurationForm(array &$form, FormStateInterface $form_state) {
    parent::validateConfigurationForm($form, $form_state);
    $radius = (int) $form_state
      ->getValue('radius');
    $sigma = (double) $form_state
      ->getValue('sigma');
    if ($radius < $sigma) {
      $form_state
        ->setError($form, $this
        ->t("The value of <em>sigma</em> must be lower than the <em>radius</em>."));
    }
  }

  /**
   * {@inheritdoc}
   */
  public function submitConfigurationForm(array &$form, FormStateInterface $form_state) {
    parent::submitConfigurationForm($form, $form_state);
    $this->configuration['radius'] = $form_state
      ->getValue('radius');
    $this->configuration['sigma'] = $form_state
      ->getValue('sigma');
  }

  /**
   * {@inheritdoc}
   */
  public function applyEffect(ImageInterface $image) {
    return $image
      ->apply('gaussian_blur', [
      'radius' => $this->configuration['radius'],
      'sigma' => $this->configuration['sigma'],
    ]);
  }

}

Members

Name	Modifiers	Type	Description	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		1
DependencySerializationTrait::__wakeup	public	function		2
GaussianBlurImageEffect::applyEffect	public	function	Applies an image effect to the image object. Overrides ImageEffectInterface::applyEffect
GaussianBlurImageEffect::buildConfigurationForm	public	function	Form constructor. Overrides PluginFormInterface::buildConfigurationForm
GaussianBlurImageEffect::defaultConfiguration	public	function	Gets default configuration for this plugin. Overrides ImageEffectBase::defaultConfiguration
GaussianBlurImageEffect::getSummary	public	function	Returns a render array summarizing the configuration of the image effect. Overrides ImageEffectBase::getSummary
GaussianBlurImageEffect::submitConfigurationForm	public	function	Form submission handler. Overrides ConfigurableImageEffectBase::submitConfigurationForm
GaussianBlurImageEffect::validateConfigurationForm	public	function	Form validation handler. Overrides ConfigurableImageEffectBase::validateConfigurationForm
ImageEffectBase::$logger	protected	property	A logger instance.
ImageEffectBase::$uuid	protected	property	The image effect ID.
ImageEffectBase::$weight	protected	property	The weight of the image effect.
ImageEffectBase::calculateDependencies	public	function	Calculates dependencies for the configured plugin. Overrides DependentPluginInterface::calculateDependencies
ImageEffectBase::create	public static	function	Creates an instance of the plugin. Overrides ContainerFactoryPluginInterface::create
ImageEffectBase::getConfiguration	public	function	Gets this plugin's configuration. Overrides ConfigurableInterface::getConfiguration
ImageEffectBase::getDerivativeExtension	public	function	Returns the extension of the derivative after applying this image effect. Overrides ImageEffectInterface::getDerivativeExtension	1
ImageEffectBase::getUuid	public	function	Returns the unique ID representing the image effect. Overrides ImageEffectInterface::getUuid
ImageEffectBase::getWeight	public	function	Returns the weight of the image effect. Overrides ImageEffectInterface::getWeight
ImageEffectBase::label	public	function	Returns the image effect label. Overrides ImageEffectInterface::label
ImageEffectBase::setConfiguration	public	function	Sets the configuration for this plugin instance. Overrides ConfigurableInterface::setConfiguration
ImageEffectBase::setWeight	public	function	Sets the weight for this image effect. Overrides ImageEffectInterface::setWeight
ImageEffectBase::transformDimensions	public	function	Determines the dimensions of the styled image. Overrides ImageEffectInterface::transformDimensions	4
ImageEffectBase::__construct	public	function	Constructs a \Drupal\Component\Plugin\PluginBase object. Overrides PluginBase::__construct
MessengerTrait::$messenger	protected	property	The messenger.	29
MessengerTrait::messenger	public	function	Gets the messenger.	29
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::$pluginId	protected	property	The plugin_id.
PluginBase::DERIVATIVE_SEPARATOR		constant	A string which is used to separate base plugin IDs from the derivative ID.
PluginBase::getBaseId	public	function	Gets the base_plugin_id of the plugin instance. Overrides DerivativeInspectionInterface::getBaseId
PluginBase::getDerivativeId	public	function	Gets the derivative_id of the plugin instance. Overrides DerivativeInspectionInterface::getDerivativeId
PluginBase::getPluginDefinition	public	function	Gets the definition of the plugin implementation. Overrides PluginInspectionInterface::getPluginDefinition	3
PluginBase::getPluginId	public	function	Gets the plugin_id of the plugin instance. Overrides PluginInspectionInterface::getPluginId
PluginBase::isConfigurable	public	function	Determines if the plugin is configurable.
StringTranslationTrait::$stringTranslation	protected	property	The string translation service.	1
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.