[svn:osmf:] 13002: Some fixes for the composite view trait.

Question

Revision: 13002
Revision: 13002
Author:   [email protected]
Date:     2009-12-16 13:04:30 -0800 (Wed, 16 Dec 2009)
Log Message:
Some fixes for the composite view trait.  Integrated some of the unit tests (though some still break and are commented out).
Modified Paths:
    osmf/trunk/framework/MediaFramework/org/osmf/composition/CompositeViewTrait.as
    osmf/trunk/framework/MediaFramework/org/osmf/composition/ParallelViewTrait.as
    osmf/trunk/framework/MediaFramework/org/osmf/composition/SerialViewTrait.as
    osmf/trunk/framework/MediaFramework/org/osmf/layout/LayoutContextSprite.as
    osmf/trunk/framework/MediaFrameworkFlexTest/org/osmf/MediaFrameworkTests.as
    osmf/trunk/framework/MediaFrameworkFlexTest/org/osmf/composition/TestParallelElement.as
    osmf/trunk/framework/MediaFrameworkFlexTest/org/osmf/composition/TestSerialElement.as
    osmf/trunk/framework/MediaFrameworkFlexTest/org/osmf/utils/DynamicMediaElement.as
Added Paths:
    osmf/trunk/framework/MediaFrameworkFlexTest/org/osmf/composition/TestParallelElementWithV iewTrait.as
    osmf/trunk/framework/MediaFrameworkFlexTest/org/osmf/composition/TestSerialElementWithVie wTrait.as

Answer 1

It's important to understand what traits are and what they're not:
Traits are not intended to be generically extensible:  there's a fixed set within the framework (although we may add additional traits in the future, to support new Flash/FMS capabilities).  We experimented with making them fully extensible, but it turned out to be not worth the cost, particularly since there shouldn't be that many traits in a media system.
Traits represent fundamental characteristics or capabilities of the media in its context.  For example, some media is playable (videos), other media is not (images).
A trait cannot apply to all media types.  If it could, then there would be no reason to model it as a trait, instead we would model it as part of the MediaElement.  Metadata is a good example of this, in that any MediaElement might have some metadata associated with it, so it wouldn't make sense to make metadata a trait.  Similarly, any MediaElement has the ability to go into fullscreen mode, so I wouldn't model the ability to go fullscreen as a trait.
On a semi-related note, I'm often asked (inside Adobe and elsewhere) for a technical overview of OSMF.  I've posted the slides that I use for this purpose here:
https://sourceforge.net/adobe/osmf/wiki/_discuss/thread/d6c3d719/1962/attachment/OSMF%20Ar chitectural%20Building%20Blocks.pdf
The slides cover the fundamental building blocks of OSMF, things you are likely to use over and over if you're building complex media experiences.  They might shed some light on which different parts of OSMF should be used in which situations.