ExifHiddenWidget.php

<?php

namespace Drupal\exif\Plugin\Field\FieldWidget;

use Drupal\Core\Field\FieldItemListInterface;
use Drupal\Core\Form\FormStateInterface;

/**
 * Plugin implementation of the 'exif_readonly' widget.
 *
 * @FieldWidget(
 *   id = "exif_hidden",
 *   label = @Translation("metadata from image (hidden in forms)"),
 *   description = @Translation("field content is calculated from image field
 *   in the same content type (field are hidden from forms)"), multiple_values
 *   = true, field_types = {
 *     "string",
 *     "string_long",
 *     "text",
 *     "text_with_summary",
 *     "text_long",
 *     "entity_reference",
 *     "date",
 *     "datetime",
 *     "datestamp"
 *   }
 * )
 */
class ExifHiddenWidget extends ExifFieldWidgetBase {
    
    /**
     * Implements callback of formElement.
     *
     * @param array $element
     *   A form element array containing basic properties for the widget.
     * @param \Drupal\Core\Form\FormStateInterface $form_state
     *   The current state of the form.
     * @param array $form
     *   The form structure where widgets are being attached to.
     *
     * @return array
     *   The form elements for a single widget for this field.
     */
    public static function process(array $element, FormStateInterface $form_state, array $form) {
        $element['tid'] = [
            '#type' => 'hidden',
            '#value' => '',
        ];
        $element['value'] = [
            '#type' => 'hidden',
            '#value' => '',
        ];
        $element['timezone'] = [
            '#type' => 'hidden',
            '#value' => '',
        ];
        $element['value2'] = [
            '#type' => 'hidden',
            '#value' => '',
        ];
        $element['display'] = [
            '#type' => 'hidden',
            '#value' => '',
        ];
        return $element;
    }
    
    /**
     * {@inheritdoc}
     */
    public function formElement(FieldItemListInterface $items, $delta, array $element, array &$form, FormStateInterface $form_state) {
        $element += [
            '#type' => '#hidden',
            '#value' => '',
            '#process' => [
                [
                    get_class($this),
                    'process',
                ],
            ],
        ];
        return $element;
    }

}