Validity and Semantics - Two Essential Parts of a Backbone for an Automated PDF/UA Compliance Check

13th International Conference, ICCHP 2012 - Linz, Austria, July 2012

Markus Erle (Wertewerk) / Samuel Hofer (xyMedia)

1. Starting Point

2. Our Approach and Results

3. The Impact and Future Work

Agenda

1. Starting Point

3 Main Questions

• How important is validity for accessible PDF documents?

• How can the document structure be checked even by users with basic accessibility knowledge?

• How can the PDF accessibility checker (PAC) be improved to a PDF/UA Compliance Check?

2. Our Approach and Results

Is Validity relevant for Accessible PDF Documents?

• PDF/UA emphasizes validity as an essential requirement

• validity can help to check a document automatically (at least some aspects like the tag syntax)

• without validity a PDF document may not be compatible „with current and future user agents, including assistive technologies“ (WCAG 2.0, success criteria 4.1.1)

Is Validity relevant for Accessible PDF Documents?

• PDF/UA emphasizes validity as an essential requirement

• validity can help to check a document automatically (at least some aspects like the tag syntax)

• without validity a PDF document may not be compatible „with current and future user agents, including assistive technologies“ (WCAG 2.0, success criteria 4.1.1)

Yes!

How to check the Validity of the Syntax?

• special tool is necessary

• we developed a new query language called PQL (PDF Query Language)

• PQL enables to select objects from a PDF document by a variety of criteria

• PQL allows to define checks which validate the PDF structures

How to check the Validity of the Syntax?

• special tool is necessary

• we developed a new query language called PQL (PDF Query Language)

• PQL enables to select objects from a PDF document by a variety of criteria

• PQL allows to define checks which validate the PDF structures

With PQL!

How to Support an Easy Check for Semantics?

• Semantics are an essential requirement for accessible PDFs

• the evaluation of the document structure according to correct semantics cannot be performed by automated tools

• a special preview - „screenreader preview“ - can support the evaluator

How to Support an Easy Check for Semantics?

• Semantics are an essential requirement for accessible PDFs

• the evaluation of the document structure according to correct semantics cannot be performed by automated tools

• a special preview - „screenreader preview“ - can support the evaluator

With a Screenreader

Preview!

3. The Impact and Future Work

PDF Accessibility Checker 2

• The foundation „Access for All“ with support of the PDF Association initiated a crowd funding for realizing PAC 2 as a free available and easy-to-use PDF/UA compliance check

• It is based on PQL and contains a validity check and an improved preview function

• A first version will be downloadable during the fourth quarter 2012

Thank you!Feel free to ask questions!

http://www.access-for-all.ch/en/pdf-lab/pdf-accessibility-checker-pac/donation-pac-2.html