5 * Autogenerates PDF preview into an image field.
9 * Implements hook_entity_presave().
11 function pdf_to_imagefield_entity_presave(Drupal\Core\Entity\EntityInterface $entity) {
12 if ($entity instanceof \Drupal\Core\Entity\ContentEntityInterface) {
13 foreach ($entity->getFieldDefinitions() as $field_definition) {
14 if ($field_definition->getType() == 'file' && $field_definition->getThirdPartySetting('pdf_to_imagefield', 'enable')) {
15 $image_style = \Drupal::entityTypeManager()->getStorage('image_style')->load($field_definition->getThirdPartySetting('pdf_to_imagefield', 'image_style'));
16 $target_field = $entity->getFieldDefinition($field_definition->getThirdPartySetting('pdf_to_imagefield', 'target_field'));
17 $force_image_toolkit = $field_definition->getThirdPartySetting('pdf_to_imagefield', 'force_image_toolkit_enable') && $field_definition->getThirdPartySetting('pdf_to_imagefield', 'force_image_toolkit') ? $field_definition->getThirdPartySetting('pdf_to_imagefield', 'force_image_toolkit') : FALSE;
19 if ($image_style && $target_field) {
20 $files = array_map(function ($item) {
21 return $item['target_id'];
22 }, $entity->get($field_definition->getName())->getValue());
24 $file_entities = !empty($files) ? \Drupal::entityTypeManager()->getStorage($field_definition->getFieldStorageDefinition()->getSetting('target_type'))->loadMultiple($files) : [];
25 // Now we remap the file entities array from being keyed by fid to
26 // being keyed by delta.
28 foreach ($entity->get($field_definition->getName())->getValue() as $delta => $item) {
29 $files[$delta] = $file_entities[$item['target_id']];
32 $original_entity = isset($entity->original) ? $entity->original : NULL;
33 if (!$entity->isNew() && $entity->isNewRevision()) {
34 // If it is a new revision, the $entity->original will have a
35 // pointer the "current" revision. While we need the just previous
36 // revision in order to see if files and previews have changed. At
37 // least paragraphs module does not promote its new revisions as
38 // "current", so we need this hack in order to recognize truly
39 // "latest" revision when running on paragraph entities.
40 // TODO: is there any better way to find the latest (not current)
41 // revision of an entity than using its entity query?
42 $query = \Drupal::entityTypeManager()->getStorage($entity->getEntityTypeId())->getQuery();
43 $query->allRevisions();
44 $query->condition($entity->getEntityType()->getKey('id'), $entity->id());
45 if ($entity->isTranslatable()) {
46 $query->condition($entity->getEntityType()->getKey('langcode'), $entity->language()->getId());
48 $revision_id = max(array_keys($query->execute()));
50 // The revision might be not available, if that's a translatable
51 // entity whose new translation is being saved right now.
53 $original_entity = \Drupal::entityTypeManager()->getStorage($entity->getEntityTypeId())->loadRevision($revision_id);
57 if ($entity->isTranslatable() && $original_entity && $original_entity->hasTranslation($entity->language()->getId())) {
58 $original_entity = $original_entity->getTranslation($entity->language()->getId());
61 $old_files = isset($original_entity) ? $original_entity->get($field_definition->getName())->getValue() : [];
63 // We only override missing previews, this way there is still a
64 // possibility to specify the preview images through other means (be
65 // it programmatically or via UI).
66 $previews = array_slice($entity->get($target_field->getName())->getValue(), 0, count($files));
67 $old_previews = isset($original_entity) ? $original_entity->get($target_field->getName())->getValue() : [];
69 foreach ($files as $delta => $file) {
70 // We only change preview if it is missing or the underlying file
71 // has changed while its preview has not been updated.
72 $is_file_changed = (isset($files[$delta]) xor isset($old_files[$delta])) || $files[$delta]->id() != $old_files[$delta]['target_id'];
74 $is_preview_changed = (isset($previews[$delta]) xor isset($old_previews[$delta]));
75 if (isset($previews[$delta]['target_id']) && isset($old_previews[$delta]['target_id'])) {
76 $is_preview_changed = $is_preview_changed || $previews[$delta]['target_id'] != $old_previews[$delta]['target_id'];
79 if ((!isset($previews[$delta]) || ($is_file_changed && !$is_preview_changed)) && $file->getMimeType() == 'application/pdf') {
80 $target_uri = $image_style->buildUri($file->getFileUri());
81 if ($force_image_toolkit) {
82 // Unfortunately, ImageStyle::createDerivative does not use
83 // dependency injection correctly. It accesses
84 // \Drupal::service() directly instead of injecting its
85 // dependencies in constructor.
86 // So we just outsmart it by temporarily swapping the active
88 $image_factory = \Drupal::service('image.factory');
89 $real_image_toolkit = $image_factory->getToolkitId();
90 $image_factory->setToolkitId('imagemagick');
92 $image_style->flush($file->getFileUri());
93 $image_style->createDerivative($file->getFileUri(), $target_uri);
95 if ($force_image_toolkit) {
96 // Now revert back the toolkit in the global image factory.
97 $image_factory->setToolkitId($real_image_toolkit);
100 $new_preview = \Drupal::entityTypeManager()->getStorage($target_field->getFieldStorageDefinition()->getSetting('target_type'))->create([
101 'uid' => \Drupal::currentUser()->id(),
102 'uri' => $target_uri,
104 $new_preview->setPermanent();
105 $new_preview->save();
106 $new_preview = $new_preview->id();
108 $previews[$delta] = [
109 'target_id' => $new_preview,
110 'alt' => t('Preview of @file_name', [
111 '@file_name' => $file->getFilename(),
117 $entity->set($target_field->getName(), $previews);
125 * Implements hook_imagemagick_arguments_alter().
127 function pdf_to_imagefield_imagemagick_arguments_alter(\Drupal\imagemagick\Plugin\ImageToolkit\ImagemagickToolkit $toolkit, $command) {
130 // TODO: For some reason some versions/setups of ImageMagick do not
131 // correctly recognize PDF mime-type, so we additionally check for
132 // extension. So far no side effects have been reported regarding this
134 if ($toolkit->getSourceFormat() == 'PDF' || preg_match('#\.pdf$#i', $toolkit->getSource())) {
135 // Insert the -flatten argument right after reading the PDF file.
136 // Otherwise the resulting images may have issues with background
138 $toolkit->prependArgument('-flatten');
145 * Implements hook_form_FORM_ID_alter().
147 function pdf_to_imagefield_form_field_config_edit_form_alter(&$form, \Drupal\Core\Form\FormStateInterface $form_state) {
148 $field_config = $form_state->getBuildInfo()['callback_object']->getEntity();
150 if (pdf_to_imagefield_is_eligible($field_config)) {
151 // Since this file field accepts PDFs, we can hook in with our stuff.
152 $form['third_party_settings']['pdf_to_imagefield'] = array(
153 '#type' => 'fieldset',
154 '#title' => t('PDF preview autogeneration'),
157 $form['third_party_settings']['pdf_to_imagefield']['enable'] = array(
158 '#type' => 'checkbox',
159 '#title' => t('Generate 1st page preview'),
160 '#description' => t('Automatically generate 1st page PDF preview and save it into an arbitrary image field on the same entity.'),
161 '#default_value' => $field_config->getThirdPartySetting('pdf_to_imagefield', 'enable'),
164 // The rest of our settings should be visible only if the feature is
168 ':input[name$="[pdf_to_imagefield][enable]"]' => ['checked' => TRUE],
172 $form['third_party_settings']['pdf_to_imagefield']['target_field'] = array(
174 '#title' => t('Store 1st page image preview in'),
175 '#description' => t('Specify an image field where the 1st page preview of the PDF should be saved.'),
176 '#options' => pdf_to_imagefield_allowed_image_fields($field_config->getTargetEntityTypeId(), $field_config->getTargetBundle()),
177 '#states' => $states,
178 '#default_value' => $field_config->getThirdPartySetting('pdf_to_imagefield', 'target_field'),
181 $form['third_party_settings']['pdf_to_imagefield']['image_style'] = array(
183 '#title' => t('Image style'),
184 '#description' => t('Specify image style to use for PDF to image conversion.'),
185 '#options' => pdf_to_imagefield_allowed_image_styles(),
186 '#states' => $states,
187 '#default_value' => $field_config->getThirdPartySetting('pdf_to_imagefield', 'image_style'),
190 $form['third_party_settings']['pdf_to_imagefield']['force_image_toolkit_enable'] = array(
191 '#type' => 'checkbox',
192 '#title' => t('Force a specific image toolkit'),
193 '#description' => t('Force to use a specific image toolkit for PDF to image conversion instead of the default image toolkit.'),
194 '#default_value' => $field_config->getThirdPartySetting('pdf_to_imagefield', 'force_image_toolkit_enable'),
195 '#states' => $states,
198 $image_toolkit_options = [];
199 foreach (\Drupal::service('image.toolkit.manager')->getAvailableToolkits() as $id => $definition) {
200 $image_toolkit_options[$id] = $definition['title'];
203 $form['third_party_settings']['pdf_to_imagefield']['force_image_toolkit'] = array(
205 '#title' => t('Image toolkit to force'),
206 '#options' => $image_toolkit_options,
207 '#default_value' => $field_config->getThirdPartySetting('pdf_to_imagefield', 'force_image_toolkit'),
208 '#states' => array_merge_recursive($states, ['visible' => [
209 ':input[name$="[pdf_to_imagefield][force_image_toolkit_enable]"]' => ['checked' => TRUE],
216 * Determine whether the field config is eligible for PDF to image manipulation.
218 * @param \Drupal\Core\Field\FieldConfigInterface $field_config
219 * Field config entity object whose eligibility to determine
222 * Whether the provided field config entity is eligible for PDF to image
225 function pdf_to_imagefield_is_eligible(\Drupal\Core\Field\FieldConfigInterface $field_config) {
226 return $field_config->getType() == 'file' && preg_match('/(^|\s|,)pdf($|\s|,)/i', $field_config->getSetting('file_extensions'));
230 * Fetch a list of image fields where the preview could be saved.
232 * @param string $entity_type
233 * Entity type where to conduct the search of allowed image fields
234 * @param string $bundle
235 * Bundle where to conduct the search of allowed image fields
238 * Array of possible field names where PDF preview could be saved. Keys are
239 * field names whereas values are their human labels
241 function pdf_to_imagefield_allowed_image_fields($entity_type, $bundle) {
242 $allowed_values = [];
244 foreach (\Drupal::service('entity_field.manager')->getFieldDefinitions($entity_type, $bundle) as $field_definition) {
245 if ($field_definition->getType() == 'image') {
246 $allowed_values[$field_definition->getName()] = $field_definition->getLabel();
250 return $allowed_values;
254 * Fetch a list of eligible image styles that can be used for PDF conversion.
257 * Array of possible image styles that can be used for PDF preview
258 * generation. Keys are image style machine-names whereas values are their
261 function pdf_to_imagefield_allowed_image_styles() {
262 $allowed_values = [];
264 foreach (\Drupal::entityTypeManager()->getStorage('image_style')->loadMultiple() as $image_style) {
265 $allowed_values[$image_style->id()] = $image_style->label();
268 return $allowed_values;