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class Signature in SignatureField 1.x

Provides a form element for a signature.

Plugin annotation

@FormElement("signature");

Hierarchy

Expanded class hierarchy of Signature

1 string reference to 'Signature'
SignatureFormatter::viewElements in src/Plugin/Field/FieldFormatter/SignatureFormatter.php
Builds a renderable array for a field value.
1 #type use of Signature
SignaturePadWidget::formElement in src/Plugin/Field/FieldWidget/SignaturePadWidget.php
Returns the form for a single field widget.

File

src/Element/Signature.php, line 14

Namespace

Drupal\signaturefield\Element
View source 
class Signature extends FormElement {

  /**
   * {@inheritdoc}
   */
  public function getInfo() {
    return [
      '#input' => TRUE,
      '#width' => '400',
      '#height' => '200',
      '#pen_color' => 'black',
      '#background_color' => 'rgba(0, 0, 0, 0)',
      '#default_value' => NULL,
      '#element_validate' => [
        [
          static::class,
          'validateElement',
        ],
      ],
      '#process' => [
        [
          static::class,
          'processElement',
        ],
      ],
      '#theme_wrappers' => [
        'form_element',
      ],
    ];
  }

  /**
   * Validate a signature element.
   *
   * @param array $element
   *   The element being validated.
   * @param \Drupal\Core\Form\FormStateInterface $form_state
   *   The current state of the form.
   * @param array $complete_form
   *   The complete form structure.
   */
  public static function validateElement(array &$element, FormStateInterface $form_state, array &$complete_form) {
    if ($element['#value'] === '') {
      return;
    }
    if (strpos($element['#value'], 'data:image/png;base64,') !== 0) {
      $form_state
        ->setError($element, t('No valid signature has been submitted.'));
      return;
    }

    // Create a temporary file for validation.

    /** @var \Drupal\Core\File\FileSystemInterface $file_system */
    $file_system = \Drupal::service('file_system');
    $directory = $file_system
      ->realpath('temporary://');
    if (!($file = tempnam($directory, 'signature'))) {
      $form_state
        ->setError($element, t('The signature image could not be validated.'));
      return;
    }
    try {

      // Save the image.
      file_put_contents($file, base64_decode(mb_substr($element['#value'], 21)));

      // Validate it.

      /** @var \Drupal\Core\Image\ImageFactory $image_factory */
      $image_factory = \Drupal::service('image.factory');
      $image = $image_factory
        ->get($file);
      if (!$image
        ->isValid() || $image
        ->getMimeType() !== 'image/png') {
        $form_state
          ->setError($element, t('No valid signature has been submitted.'));
      }
    } finally {
      unlink($file);
    }
  }

  /**
   * Processes a signature element.
   *
   * @param array $element
   *   The element being processed.
   * @param \Drupal\Core\Form\FormStateInterface $form_state
   *   The current state of the form.
   * @param array $complete_form
   *   The complete form structure.
   *
   * @return array
   *   The altered form element.
   */
  public static function processElement(array $element, FormStateInterface $form_state, array $complete_form) {
    $value_id = Html::getUniqueId('signature-value');
    $canvas_id = Html::getUniqueId('signature-canvas');
    $element['value'] = [
      '#type' => 'hidden',
      '#default_value' => $element['#value'],
      '#parents' => $element['#parents'],
      '#attributes' => [
        'id' => $value_id,
      ],
    ];
    $element['canvas'] = [
      '#theme' => 'signature_canvas',
      '#id' => $canvas_id,
      '#width' => $element['#width'],
      '#height' => $element['#height'],
    ];
    $element['#attached']['library'][] = 'signaturefield/signature';
    $element['#attached']['drupalSettings']['signaturefield'][$canvas_id] = [
      'valueId' => $value_id,
      'penColor' => $element['#pen_color'],
      'backgroundColor' => $element['#background_color'],
    ];
    return $element;
  }

}

Members

Namesort descending Modifiers Type Description Overrides
DependencySerializationTrait::$_entityStorages protected property
DependencySerializationTrait::$_serviceIds protected property
DependencySerializationTrait::__sleep public function 2
DependencySerializationTrait::__wakeup public function 2
FormElement::processAutocomplete public static function Adds autocomplete functionality to elements.
FormElement::processPattern public static function #process callback for #pattern form element property.
FormElement::validatePattern public static function #element_validate callback for #pattern form element property.
FormElement::valueCallback public static function Determines how user input is mapped to an element's #value property. Overrides FormElementInterface::valueCallback 15
MessengerTrait::$messenger protected property The messenger. 27
MessengerTrait::messenger public function Gets the messenger. 27
MessengerTrait::setMessenger public function Sets the messenger.
PluginBase::$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 public function Determines if the plugin is configurable.
PluginBase::__construct public function Constructs a \Drupal\Component\Plugin\PluginBase object. 98
RenderElement::preRenderAjaxForm public static function Adds Ajax information about an element to communicate with JavaScript.
RenderElement::preRenderGroup public static function Adds members of this group as actual elements for rendering.
RenderElement::processAjaxForm public static function Form element processing handler for the #ajax form property. 1
RenderElement::processGroup public static function Arranges elements into groups.
RenderElement::setAttributes public static function Sets a form element's class attribute. Overrides ElementInterface::setAttributes
Signature::getInfo public function Returns the element properties for this element. Overrides ElementInterface::getInfo
Signature::processElement public static function Processes a signature element.
Signature::validateElement public static function Validate a signature element.
StringTranslationTrait::$stringTranslation protected property The string translation service. 4
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.