XML News from Monday, March 21, 2005

The W3C Compound Document Formats Working Group has published the first public Working Draft of Compound Document by Reference Use Cases and Requirements. "A compound document combines multiple formats, such as XHTML, SVG, XForms, MathML and SMIL. This draft introduces compounding by a reference like img, object, link, src and XLink. Compounding by inclusion is planned for a later phase." I think this goes a little beyond specs like XLink and XInclude, in seeking to specify not just how an XML infoset is created from compound documents, but how DOM and various behaviors extend and interoperate across different namespaces used or referenced in the same document. High-Level Requirements are listed as:

• CDR MUST exploit existing specifications, favoring W3C specifications wherever possible
• CDR SHOULD NOT define new markup unless absolutely required for integration purposes
• CDR MUST provide the ability to define Rich Multimedia Content
• CDR MUST specify a base set of formats, corresponding profiles and versions
• Each CDR profile and version MUST specify, which formats can be referenced
• CDR MUST specify, for each format, the element used to reference other formats, if any.
• CDR MAY specify generic integration techniques
• CDR MUST support temporal synchronisation of dynamic content coming from multiple references, possibly with multiple references to the same source.
• CDR MUST ensure that user agent controls work consistently regardless of the component that has focus
• CDR MUST support event mechanisms that cross namespace boundaries
• CDR MUST support scriptability
• CDR MUST say the allowed nesting level of referencing
• CDR MUST explain how scripting interacts between components and the host document
• CDR MUST explain which events get dispatched to the referenced document
• CDR profiles MUST define how eventing (such as events, focus or links) work across namespaces
• CDR profiles MUST specify how event propagation works across namespace boundaries.
• CDR profiles MUST specify how focus traversal works with referenced documents.
• CDR profiles MUST specify how link activation work with referenced document.
• CDR profiles MUST specify triggering of animations across namespaces.
• CDR MUST support fragment identifiers in cross-namespace interaction
• CDR MUST support a unified rendering model
• CDR profiles SHOULD provide a method for adding event handlers using declarative markup for the formats it uses
• CDR documents MUST cater for accessibility requirements
• CDR documents MUST support dynamic updating
• CDR must define its integration into the Web Architecture. It must include delivery over HTTP and should also strive to be transport independent
• CDR MUST allow compression of the data
• CDR MUST allow packaging of the data
• CDR MUST define the sharing of fonts among all components of a document
• CDR MUST support server-side adaptation
• CDR MUST support limited bandwidth networks and limited capability devices

Requirements for CDR Profile 1 (Rich Multimedia Content) are given as:

• CDR Profile 1 MUST support user interaction model
• CDR Profile 1 MUST explain how User Agent is able to identify a CDR Profile 1 document
• CDR Profile 1 MUST support scalable graphics
• CDR Profile 1 MUST support audio
• CDR Profile 1 MUST support grid, flow, overlapping layouts
• CDR Profile 1 MUST define transparency support for SVG backgrounds
• CDR Profile 1 MAY define transparency support for XHTML backgrounds
• CDR Profile 1 MUST support identification of markup and versions in CDF documents
• CDR Profile 1 MUST support scalable diagrams that can be animated and can cause link traversal
• CDR Profile 1 MUST define how to reference SVGT graphics and resources from an XHTML document
• CDR Profile 1 MUST support advertising the specific supported versions of formats and capabilities in headers
• CDR Profile 1 MUST support XHTML as a root/host language
• The XHTML <object> element MUST be used for referring to other formats from XHTML
• CDR Profile 1 MUST support Non-interactive Background SVG
• CDR Profile 1 MUST define for animated SVG icons to act like HTML images (no need for interactivity, links, zoom and pan)
• CDR Profile 1 MUST define a way for events to trigger SVG animation
• CDR Profile 1 MUST define how an XHTML document can reference an SVG Tiny document
• CDR Profile 1 MUST define the interaction model for an SVG document referenced by an XHTML document
• CDR Profile 1 MUST define the process for real-estate negotiation between an XHTML document and a referenced SVG document
• CDR Profile 1 MUST define handling of leftover SVG area
• CDR Profile 1 MUST define system font support in SVG