Inside Macintosh: QuickTime Reference

New Target Type Atoms for Hierarchical Movies

There are new target atoms added to accommodate the addition of embedded movies in QuickTime 4.1. They allow for paths to be specified in a hierarchical movie tree.

Target movies may be an external movie, the default movie, or any movie embedded within another movie. Targets are specified using a movie path that may include parent and child movie relationships, and may additionally include track and track object target atoms as needed.

By using embedded kActionTarget atoms along with new parent and child movie target atoms, you can build up paths for movie targets. Note that we only look for these embedded kActionTargetAtoms when evaluating a movie target, and any movie target type may contain a sibling kActionTargetAtom.

Paths start from the current movie, which is the movie containing the object that is handling an event. You may go up the tree using a new kTargetParentMovie atom or down the tree using one of five new child movie atoms. You may use a new kTargetRootMovie atom as a shortcut to get to the top of the tree containing an embedded movie and may use the existing movieByName and movieByID atoms to specify a root external movie.

The new target atoms are described below. Note that there are five ways to specify an embedded child movie. Three of them specify MovieTrack properties. Two specify properties of the currently loaded movie in a movie track.

kTargetRootMovie (leaf atom -- no data): The root movie containing the action handler.
kTargetParentMovie (leaf atom -- no data): The parent movie.

kTargetChildMovieTrackName [Pstring movieTrackName]

A child movie track specified by track name.

kTargetChildMovieTrackID [QTAtomID movieTrackID]

A child movie track specified by track ID.

kTargetChildMovieTrackIndex [long movieTrackIndex]

A child movie track specified by track index.

kTargetChildMovieMovieName [Pstring movieName]

A child movie specified by the currently loaded movie's movie name. The child movie must contain movieName user data with the specified name.

kTargetChildMovieMovieID [QTAtomID movieID]

A child movie specified by the currently loaded movie's movie ID. The child movie must contain movieID user data with the specified ID.

Inside Macintosh: QuickTime Reference