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