class ImageResize

class ImageResize extends CKEditor5PluginDefault implements CKEditor5PluginConfigurableInterface {
  use CKEditor5PluginConfigurableTrait;
  
  /**
   * {@inheritdoc}
   */
  public function defaultConfiguration() {
    return [
      'allow_resize' => TRUE,
    ];
  }
  
  /**
   * {@inheritdoc}
   */
  public function buildConfigurationForm(array $form, FormStateInterface $form_state) {
    $form['allow_resize'] = [
      '#type' => 'checkbox',
      '#title' => $this->t('Allow the user to resize images'),
      '#default_value' => $this->configuration['allow_resize'],
    ];
    return $form;
  }
  
  /**
   * {@inheritdoc}
   */
  public function validateConfigurationForm(array &$form, FormStateInterface $form_state) {
    // Match the config schema structure at
    // ckeditor5.plugin.ckeditor5_imageResize.
    $form_value = $form_state->getValue('allow_resize');
    $form_state->setValue('allow_resize', (bool) $form_value);
  }
  
  /**
   * {@inheritdoc}
   */
  public function submitConfigurationForm(array &$form, FormStateInterface $form_state) {
    $this->configuration['allow_resize'] = $form_state->getValue('allow_resize');
  }

}