Who's afraid of XFA?

A PDF Association Presentation · © 2015 by PDF Association · www.pdfa.org

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2015-06-08

Bruno Lowagie,Founder/CEO iText Groupitextpdf.com

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PDF Days Europe 2015

Who’s Afraid of XFA?

Bruno LowagieFounder/CEO of the iText Group

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2015-06-08


Do you know XFA?

Question 1:

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Do you really know XFA?

Question 2:

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Are you afraid of XFA?

Question 3:

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Votes against XFA

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Results of a PDF Association survey

ISO 32000 ballot

Documentation and ballot result


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What is XFA?

What is this about?

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AcroForm technology

• Introduced in PDF 1.2 (1996).

• Uses PDF syntax: AcroForm dictionary, Fields array, Field dictionary, Widget annotation,…

• Data consists of key value pairs with limited hierarchy.

• Static: position of every field is fixed, specific rectangle(s) on specific page(s).

• The technology is standardized, but it didn’t evolve; it lacks some essential functionality.

XML Forms Architecture (XFA)

• Introduced in PDF 1.5/1.6 (2003/2004).

• Defined using XML: template, datasets, data description, data,…

• .pdf: PDF as container of XML,

• .xdp: XML as container of PDF.

• Data is pure XML using an XSD of your choice.

• Dynamic: the form adapts itself to the data, repeating subforms for headers, table rows,…

• The spec is huge and not an ISO standard.

Two form technologies

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Note: in the context of this talk, I won’t be discussing hybrid forms

consisting of XFA + AcroForm aka “static XFA” aka XFAF


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AcroForm example

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AcroForms can be used as a template

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XFA example

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This form can grow dynamically

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Warning: XFA has undocumented features

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Con• Not “viewer-friendly”:

• Only “decent” support by Adobe Acrobat/Reader. Support by other viewers is inexistent to incomplete.

• No XFA on mobile devices.

• XML-based:• Slow rendering for large docs

• Too complex:• Many different ways to achieve the

same goal (supporting every possible option is a burden)

• Adobe owns XFA:• Not an ISO standard: continuity?

• Adobe’s position on XFA makes other vendors doubt if they should invest in XFA; see Foxit, Nitro, Nuance’s position towards deprecation.

Pro• Dynamic document:

• The data shapes the document,

• Fields can adapt to their content,

• Variable number of pages,…

• XML-based• You can use your own XSDs,

• There’s a clear separation of data and presentation,

• Easy to extract/exchange data.

• Functionality

• More flexibility,

• More feature-rich.

• Adoption by vendors• Adobe Acrobat/Reader, LiveCycle,

SAP Interactive forms by Adobe.

• Viewers: partial support by Foxit, Nitro, Nuance, Preview,…

• Designer: Avoka SmartForm

• Server tools by iText, IDR (e.g. IDR converts XFA to HTML 5 to render a form on mobile devices).

Some pros and cons of XFA

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Retain XFA in PDF or deprecate it? (Option B)

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Are these arguments valid?• XFA isn’t for archiving!

• XFA isn’t for engineering!

• XFA isn’t for printing!

What is XFA really about?


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What are forms used for? Let’s search Google…

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Is this really

what we do

with PDF

forms???Example: encoding


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No seriously, what are PDF forms used for?

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In many cases, PDF Forms are used as templates to

be filled out and flattened by machines!(The word “form” can be misleading in the context of PDF.)


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Creating a simple XFA template

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Importing your business logic into a dynamic form

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Custom XSD, not XFA specific!

Imported as data source


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Reorganizing the (sub)form(s)

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The result: an empty form

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Inject your XML: a filled out form

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Rendered as PDF

DATA

PRESENTATION


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The document is the data

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Your XML is here

Now flatten it into PDF 2.0, PDF/A level A, PDF/UA,…

AcroForms

would force

you to change

your schema


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Think of ZUGFeRD!

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Current approach:• Using XSLT to convert XML to intermediary format that is then converted to

PDF. For example: ZUGFeRD documentation ships with XSLT 2.0 examples

that require proprietary software (Altova).

• Using HTML? HTML is not a document format! Defining a layout in HTML is

problematic. At iText, we call it “poor man’s XFA”.

• Companies are reinventing the wheel to create PDF along with XML (which is

a lucrative business model, as long as you’re not a technology evangelist).

Possible solution:• The document is the data if you combine a CII with an XFA template.

• A multi-purpose XFA to PDF/A-3 convertor is all you need to create a

ZUGFeRD compliant invoice.

+ =CII

(extended)

Structured CII compatible

XFA template

PDF/A-3A

ZUGFeRD

machine

human


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Why is this important?

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Let’s talk about

enterprise form solutions

and workflows!

A document is never

“only” a document


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Online

registration:

forms and

data sources

Processing

data,

XML-based

workflow.

Persist,

Publish,

Sign,

Archive.

Use case: eGriffie (Belgian Department of Justice)

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Retain XFA in PDF or deprecate it? (Option A)

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and iText!


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Is there a market? Are there alternatives?

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• Is there a market for enterprise form solutions?

• Microsoft has abandoned InfoPath

• Adobe is losing the LiveCycle market (and what about SAP?)

• Customers are asking us (iText) to fill the gap

• There is a market! It is huge! It is unserved!

• Are there alternatives for XFA?

• Create PDF and XML from code: e.g. have your CRM produce

CII invoices as well as PDF/A-3 invoices and combine both

into a ZUGFeRD-compliant PDF.

• Create PDF from XML by first creating an intermediary

document and then convert this other “template” to PDF:

• Create a Word document first

• Proprietary formats (Inventive Designers, JasperSoft,…)

• XSL:FO (Apache FOP, RenderX, Inventive Designers,…)

• XSLT 2.0 (Altova)

• Forget about PDF for our enterprise documents:

• Pure XML (e.g. EDI)

• HTML 5

• Word, Open XML,…


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Is the deprecation of XFA a problem?

• No, because:

• We can keep on creating XFA templates based on ISO-32000-1

• We can convert PDF 1.7 files with XFA content to PDF 2.0, PDF/A, PDF/UA,… document, so it doesn’t matter if XFA can or can’t be used inside a PDF 2.0 document

• XDP and PDF are separate things, let’s use XDP instead of PDF (this is a suboptimal option!)

• Yes, because:

• Deprecation of XFA might be perceived as an indication that the technology will no longer be supported (which isn’t necessarily true)

• We need an XML-friendly template format that is PDF-aware, and there is no alternative for XFA

• Part of the industry might be reluctant to adopt PDF 2.0, because:

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What if we deprecated XFA only partially?

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How would we phrase this in ISO-32000-2?

• Let’s remove all the XFA-related content from ISO-32000-2 (this is already happening), but keep the XFA entry in the AcroForm dictionary (remove the word “deprecated”).

• Add: when the XFA key is present, a conforming PDF writer shall not write a Fields key.

• This deprecates static XFA (XFAF) de facto. That’s perfectly fine, because there is a valid alternative: AcroForm technology.

• This removes one of the most annoying confusions for users: being confronted with a form that contains both technologies.

• Add: when the XFA key is present, the file extension of the document shall be .xfa

• The PDF spec doesn’t define a file extension for PDF files anywhere (why would it? Not all PDF documents are files).

• However, there’s 12.7.8.1: “FDF is based on PDF; it uses the same syntax and has essentially the same file structure. However it differs from PDF (…) FDF files have the extension .fdf.”

• XFDF is another format that is mentioned in ISO-32000-2, but it’s defined completely outside ISO-32000-2.

• This way, we don’t deprecate XFA: we define it as a separate format using PDF syntax with essentially the same file structure, but with some significant differences.

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Implicitly, this means that:

• Conforming writers are allowed to create XFA templates based on the PDF 2.0 specification:

• Just like they are allowed to create FDF files!

• They use PDF 2.0 as a means to create enterprise-grade templates that are to be processed on back-end systems, not as end-user forms for people to fill out manually on the front-end.

• Conforming processors are allowed to ignore XFA, although:

• They can read the document’s objects, because the file structure is essentially a PDF file structure. Just like with some FDFs, they aren’t supposed to be able to render the full document.

• They should show a warning message similar to what happens if you want to view an FDF file without having access to the full form, or show a warning page similar to what happens when an encrypted PDF using an unsupported encryption method is encountered.

• Conforming processors are allowed to process XFA, to

• Inject XML data into a template.

• Render the XML based on the template and the business rules:

• Either to a specialized XFA viewer,

• Or to a genuine PDF file (PDF 2.0, PDF/A, PDF/UA).

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If XFA didn’t exist, we’d have to invent it, because…

• It’s an envelope for data and presentation:

• Keeping the data separated and unaltered,

• Containing rules to shape the data, eventually resulting in a page-based document.

• It’s a template format that is PDF-aware:

• You can embed PDF pages as company stationery,

• You can embed fonts, which is important if you want to convert XML to PDF/A,

• You can add real (binary) PDF objects, e.g. there’s no need to use Base64 encoding for binary content.

• It can build a bridge between XML and PDF:

• XML is the format of choice for transporting data in many different industries.

• XML is highly structured, which is important if you want to convert to Tagged PDF.

• PDF/A and PDF/UA should be the formats of choice to archive and distribute documents. XFA can become a catalyst to create such documents.

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If XFA didn’t exist, we’d have to invent it, but…

• We need to simplify it!

• Clean up the spec,

• Remove redundancy,

• Remove undocumented features.

• Evangelize it!

• Make sure it is used in the right context: templates not forms to be filled out by humans.

• Offer technology that converts XML into “smart” PDFs (PDF/A, PDF/UA) when data needs to be published for human consumption.

• Make it a standard, or at the very least:

• Make a commitment to 3rd party vendors (continuity!),

• Explore which parts we can legally use,

• Avoid having to reinvent the wheel by creating “yet another standard” as a valid alternative to XFA.

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One last question:

Who’s Afraid of XFA?

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PDF Days Europe 2015

Thank you! Any questions?

Get in touch: [email protected] site: http://www.itextpdf.comTwitter: @iText @bruno1970

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Technology

Who's afraid of XFA?