Get page number of pdf form field using php - php

Question

I am currently using SetaPDF to get the form fields located in a document and saving those form field names in a DB. However, I'm trying to get the page number of those form fields. I can't find anything in the Seta documentation that will help with this. Is there another PDF library I can use to accomplish this?
$document = SetaPDF_Core_Document::loadByFilename($file);
$formFiller = new SetaPDF_FormFiller($document);
$fields = $formFiller->getFields();
foreach ($fields->getNames() as $fieldName) {
$field = $fields->get($fieldName);
$is_read_only = 0;
if ($field->isReadOnly()) {
$is_read_only = 1;
}
$is_text = 1;
$field_name = DB::Scrub($fieldName);
$base_field_name = $field->getOriginalQualifiedName();
if (strpos($base_field_name,"#") !== false) {
$arr_field = explode("#", $base_field_name);
$base_field_name = $arr_field[0];
}
if (strpos($base_field_name,"*") !== false) {
$is_text = 0;
$base_field_name = str_replace("*","",$base_field_name);
}
$sql = "INSERT INTO [cust].[PDF_Fields] (file_name,field_name,base_field_name,is_read_only,is_text)
VALUES ('$new_file','$field_name','$base_field_name',$is_read_only,$is_text)";
DB::Query($sql);
}

Answer 1

As Ryan already wrote form fields are not directly related to a page but their representations as Widget Annotations are. This is done by adding the reference to the individual Widget Annotations in the /Annots array of the page. Sadly it is optional to have this the other way round (from the annotation to the page).
You can get the page and its number through some low level methods of the SetaPDF-Core component: First you need an instance of the Widget Annotation of a form field. This can be done with the getAnnotation() method of a form field instance.
Then you can use this instance to search the page via the getPageByAnnotation() method of the main pages instance. To get only the page number you can pass this result to the getPageNumberByPageObject() then.
The written above in code could look like:
$pages = $document->getCatalog()->getPages();
$annotation = $field->getAnnotation();
// Method name is a bit vague and accepts an annotation instance starting with revision > 1371 only
$page = $pages->getPageByAnnotation($annotation->getIndirectObject($document));
// $page = $pages->getPageByAnnotation($annotation); // works with revision > 1371
$pageNumber = $pages->getPageNumberByPageObject($page);