An interactive form (sometimes referred to as an AcroForm) is a collection of fields for gathering information interactively from the user. Under the hood, PDF form fields are a type of PDF annotation called widget annotations.


ComPDFKit PDF SDK fully supports reading, filling, creating, and editing PDF forms and provides utility methods to make working with forms simple and efficient.


Supported Form Fields


ComPDFKit PDF SDK supports all form types specified by the PDF specification (such as text boxes, checkboxes, radio buttons, drop-down lists, pushbuttons, and signatures).


CPDFWidget is the base class for all form fields, and CPDFWidget is subclass for CPDFAnnotation. A CPDFWidget object by itself is not useful, only subclasses (CPDFCheckboxWidget, CPDFRadiobuttonWidget, etc.) are interesting. In parsing a PDF however, any unknown or unsupported form fields will be filtered out.


We have to differentiate between field types and annotation objects:

Type Annotation Object
Check Boxes CPDFCheckboxWidget
Radio Buttons CPDFRadiobuttonWidget
Push Buttons CPDFPushbuttonWidget
List Boxes CPDFListboxWidget
Combo Boxes CPDFComboboxWidget
Text CPDFTextWidget
Signatures CPDFSignatureWidget