/**
  * {@inheritDocs}
  *
  * Validate callback for the focal point field.
  */
 public static function validateFocalPoint($element, FormStateInterface $form_state)
 {
     $field_name = array_pop($element['#parents']);
     $focal_point_value = $form_state->getValue($field_name);
     if (!is_null($focal_point_value) && !FocalPoint::validate($focal_point_value)) {
         \Drupal::formBuilder()->setError($element, $form_state, t('The !title field should be in the form "leftoffset,topoffset" where offsets are in percents. Ex: 25,75.', array('!title' => $element['#title'])));
     }
 }
 /**
  * Tests the validate() method.
  *
  * @dataProvider providerValidateFocalPoint
  */
 public function testFocalPointValidate($focal_point, $expected)
 {
     $this->assertSame($expected, FocalPoint::validate($focal_point));
 }