exif_orientation.module

<?php


/**
 * @file
 * Module file for EXIF Orientation.
 */
use Drupal\Core\Entity\EntityInterface;
use Drupal\Core\Form\FormStateInterface;
use Drupal\file\FileInterface;

/**
 * Implements hook_file_presave().
 */
function exif_orientation_file_presave(EntityInterface $entity) {
    // Provide EXIF Orientation correction.
    _exif_orientation_rotate($entity);
}

/**
 * Implements hook_field_widget_form_alter().
 *
 * Add a custom validator before file_validate_image_resolution().
 * file_validate_image_resolution resizes the image if it's too large losing the
 * exif data in the process.
 */
function exif_orientation_field_widget_form_alter(&$element, FormStateInterface $form_state, $context) {
    if (isset($element['#upload_validators']['file_validate_image_resolution'])) {
        $element['#upload_validators'] = [
            'exif_orientation_validate_image_rotation' => [],
        ] + $element['#upload_validators'];
    }
}

/**
 * Ensures that image orientation is according to exif data.
 *
 * @param \Drupal\file\FileInterface $file
 *   A file entity. This function may rotate the file.
 *
 * @return array
 *   An empty array.
 *
 * @see hook_file_validate()
 */
function exif_orientation_validate_image_rotation(FileInterface $file) {
    _exif_orientation_rotate($file);
    // This validator did not produce any errors.
    return [];
}

/**
 * Rotates an image to its EXIF Orientation.
 *
 * iPhone 4 and up save all images in landscape, relying on EXIF data to
 * set the orientation properly. This does not always translate well in the
 * browser or other devices.
 * @link: http://www.daveperrett.com/articles/2012/07/28/exif-orientation-handling-is-a-ghetto/
 */
function _exif_orientation_rotate($file) {
    if (function_exists('exif_read_data') && $file->getMimeType() == 'image/jpeg') {
        $file_exif = @exif_read_data(\Drupal::service('file_system')->realpath($file->getFileUri()));
        // Ensure that the Orientation key|value exists, otherwise leave.
        if (!is_array($file_exif) || !isset($file_exif['Orientation'])) {
            return;
        }
        // Orientation numbers and corresponding degrees.
        // @note: Odd numbers are flipped images, would need different process.
        switch ($file_exif['Orientation']) {
            case 3:
                $degrees = 180;
                break;
            case 6:
                $degrees = 90;
                break;
            case 8:
                $degrees = 270;
                break;
            default:
                $degrees = 0;
        }
        if ($degrees > 0) {
            $image = \Drupal::service('image.factory')->get($file->getFileUri());
            if ($image->rotate($degrees)) {
                $image->save();
            }
        }
    }
}