People have been using Adobe Acrobat to convert paper forms to electronic ones for many years now, but developments from Adobe have created confusion about the best way to create and use PDF forms. Here we will explain the different methodologies Adobe uses with forms; from the backend database to form design interface; and, how this can be problematic for those who build PDF solutions.
Multiple Standards for Forms
Adobe currently supports two methods for integrating data and PDF forms. The original method dates back to PDF 1.2 from the mid 1990’s and is known as Acrobat Forms or AcroForms. Essentially this technique involves adding the form fields as an overlay on top of the image of a form. Adobe later introduced XFA Forms (sometimes called Designer Forms) with PDF 1.5 and Acrobat 6 in 2003. Both XFA Forms and AcroForms are supported in Acrobat 6 and above, but only AcroForms are currently supported by most third-party viewers and on tablets and other mobile devices.
Acrobat Forms (AcroForms)
AcroForms are PDF files that contain form fields. Data can be entered into these fields (manually or through an automated process) by the end users or the author of the form. Internally AcroForms are annotations or fields applied to a PDF document. AcroForms are easily filled using a Forms Data Format (FDF) file; a formatted ASCII file which contains key:value pairs defining the ﬁeld names and associated values that are used to populate a form. Forms Data Format (FDF) is defined in the international stand for Portable Document Format; ISO-32000. See ISO-32000-1:2008 Section 12.7.7.
Following is an example of a simple FDF file:
1 0 obj
<< /Fields [
<< /T (ﬁeld-name-1) /V (value of ﬁeld-name-1) >>
<< /T (ﬁeld-name-2) /V (value of ﬁeld-name-2) >>
<< /Root 1 0 R >>
The AcroForm itself can be created with Adobe Acrobat 4.x and above or through many other forms design packages such as Amgraf’s OneForm Designer Plus. Users can interact with an AcroForm by using Adobe Acrobat 4.x and above or by using the free “Adobe Reader” application for one of those Adobe Acrobat versions. Adobe also provides a free utility, FDFtoolkit, to help developers build FDF files. In addition, third party developer’s tools like Appligent’s FDFMerge allow a programmer to create a system that populates (fills) high volumes of AcroForms as part of an automated process.
In 2003 Adobe introduced an XML-based version of FDF. XML FDF or XFDF was to be FDF expressed in the popular XML (Extensible Markup Language) format. XFDF support is included in Acrobat 6 (PDF 1.5) and above and represents a natural evolution of FDF technology. Like FDF XFDF is supported by many third-party software vendors.
Adobe XFA Forms (LiveCycle/Designer)
XFA Forms (XML Forms Architecture) represents a significant change in direction for Adobe from the popular FDF and XFDF methodologies. XFA Forms have their roots in a former e-forms company called JetForm later renamed Accelio and acquired by Adobe in 2002. XFA concepts were first introduced in PDF 1.5 (Acrobat 6) and expanded in PDF 1.6, (Acrobat 7). Unlike Adobe’s earlier forms technology XFA Forms utilize XML throughout. While XML is the backbone for all types of structured documents, there are distinct drawbacks to be considered:
- Creating XFA form requires Adobe LiveCycle Forms Designer which ships with Acrobat 7, 8, 9 and X Professional; and, is not included with Acrobat XI Professional.
- Adobe XFA Forms are not compatible with AcroForms, and they cannot be modified in Acrobat.
- On the backend there are no commercial or open-source alternatives to Adobe LiveCycle Enterprise Server for processing XFA Forms.
- Existing Acrobat AcroForms cannot be automatically converted to XFA Forms. Typographic fidelity may need to be sacrificed when manually redrawing the forms with LiveCycle Designer.
- Adobe XFA Form documents are not compatible with versions of Acrobat or Reader prior to 6.0.
- XFA Forms are not part of the PDF/A (Archiving) standard which is based on PDF Version 1.4. Applications for government or other institutions that must comply with digital archive standards may be problematic.
- There are no commercial or open-source alternatives to using Adobe products for XFA Forms as there are with AcroForms. If you run into problems with XFA Forms you will have no one else to call besides Adobe.
XForms vs. XFA Forms
XFA Forms should not be confused with Xforms, the W3C standard for XML-based forms. Adobe’s XFA Forms is a closed standard that competes with the fully open W3C Xforms standard. While both are XML-based the XForms standard only specifies the data and not the appearance of the form, XFA Forms specify both the form’s appearance as well as the data. XForms are not currently supported by Acrobat.
When investing in technology enterprises must do contingency planning, and enterprise PDF is no exception. Look carefully at the big picture before embracing XFA Forms. PDF forms (via AcroForms) continue to offer a viable answer for anyone who must deliver an e-Forms solution and needs to maintain one hundred percent fidelity to the original typographic document. System planners should carefully analyze the audience for their forms-based applications and consider if they can control the users desktop configuration. Simply put, can you be sure all of your potential users have Adobe Acrobat 7 or later installed, and if they don’t can you force them to install or upgrade? If not, AcroForms are the best solution. If so, further ask whether relying on a single source provider for this technology makes sense strategically.
For more information on AcroForms solutions:
TalkingPDF: Choosing Between PDF and Designer/XFA Forms