General
QDF is the exciting new format for electronic forms developed by Ringler Informatik AG and is an integral part of the platform independent SnapForm Suite.
The QDF format represents electronic form documents in a device and resolution independent format. Each QDF file encapsulates a complete description of a 2D document that includes the text, fonts, images, 2D vector graphics, styles, data fields and tables, barcodes, and data that compose the document. Importantly, QDF files don't encode information that is specific to the hardware, or operating system used to create or view the document. This feature ensures that a valid QDF will render exactly the same regardless of its origin or destination. QDF is also a free format in the sense that anyone may distribute, read, and fill in QDF files without having to pay royalties to Ringler Informatik AG.
Unlike PDF forms which need a licensed viewer to save data locally, QDF forms can be saved without any restrictions with the licence free SnapForm viewer.
Following subsets of QDF are currently available:
- QDF-S for heavily encrypted QDF files with limited accessibility
- QDF-A for archiving in corporate/ government/library/etc environments
Technology
QDF is primarily the combination of five technologies:
- a cut-down form of SVG for generating the layout and graphics in a highly structured and compact way,
- an business logics layer of vector based components and controls
- a structured data layer representing corresponding data,
- a font-embedding system to allow fonts to travel with the documents,
- a structured storage system to bundle these elements and any associated images into a single file, with data compression where appropriate.
As a document format, QDF has several advantages:
- QDF files are logically pre-formatted and therefore extremely small and fast
- QDF files contain a broad set of very powerful and patent pending input controls which makes it very efficient to fill in forms
- QDF files can calculate form data on-the-fly without having to send data out to an external server
- QDF files can exchange data via XML
- QDF also allows font embedding to ensure that the "proper" fonts are displayed. While this is possible with PostScript, such files cannot normally be distributed freely because of font licensing agreements.
QDF vs. HTML files
Documents described in markup languages such as HTML/XHTML delegate responsibility for many display decisions to the renderer. This means that an XHTML document can render quite differently across various web browser platforms. While the end user experience of an XHTML document can vary significantly depending on browser, platform, and screen resolution, a QDF file can be reasonably expected to look exactly the same to every viewer. The desire for greater control over user experience has led many authors to use the QDF format to publish online content. This is particularly true for order forms, tax forms and other documents which are primarily formatted for printing. The java based, platform independent and license free WYSIWYG authoring tool “SnapForm Viewer” further entice many form authors, especially from the government sector, to publish a wider variety of electronic forms as QDF.
QDF vs. PDF files
PDF forms programmed with java script tend to be significantly bigger than QDF forms presenting the same information, making it difficult or impossible for users with low-bandwidth connections to view them. PDF files can be imported into a QDF document as a background layer, while file size already gets reduced by up to 60%. Once a PDF file is converted to QDF, the complete business intelligence layer comprising all input objects, complex calculations, barcodes, etc., adds no more than a few kilobytes to the QDF file whereas PDF based forms usually grow by hundreds of kilobytes.
Due to Adobe’s licensing strategy, Acrobat Reader is not able to store data within a PDF form filled in by the end-user. Especially governmental institutions and companies, who want to make eforms accessible to a broad community, cannot rely on the fact, that everybody uses a licensed version of Acrobat. Therefore, they have to purchase expensive licenses from Adobe in order to patch PDF forms with additional saving rights or they need to process form data through an internet based service, which is - especially when sensitive data is involved or the user has a low-bandwidth connection - not always the best solution.
QDF with its license free SnapForm viewer, capable of storing data locally, solves these problems in a very elegant and cost efficient way.