Programming With QuickTime Sprites

QuickTime Events

When it is associated with a QuickTime movie, the movie controller checks to see if a track in the movie provides actions in response to QuickTime events. If one or more tracks provide actions, the movie controller will then monitor the activity of the mouse and send the appropriate mouse-related events.

These mouse events include: kQTEventMouseClick , kQTEventMouseClickEnd , kQTEventMouseClickEndTriggerButton , kQTEventMouseEnter , and kQTEventMouseExit .

Other types of events do not require user interaction in order to be generated.

The kQTEventIdle event is sent to each sprite in a sprite track if that sprite track's kSpriteTrackPropertyQTIdleEventsFrequency property is set to a value other than the default value kNoQTIdleEvents .

The kQTEventFrameLoaded is generated when a sprite track sample which contains actions for it is loaded.

Important
If you want the sprites in your sprite track to receive kQTEventIdle QuickTime events, you must add an atom of the type kSpriteTrackPropertyQTIdleEventsFrequency . This atom's leaf data is of type UInt32 . The value is the mimimum number of ticks that must pass before the next QTIdle event is sent. Each tick is 1/60th of one second. To specify "Idle as fast as possible," you set the value to 0. The default value is kNoQTIdleEvents which means don't send any idle events. For more information, see "New Sprite Track Property Atoms" .

If you want the movie controller to execute the actions in your sprite track's media, you must add an atom of type SpriteTrackPropertyHasActions with its leaf data set to true The atom's leaf data is of type Boolean . The default value is false , so it is very important to add an atom of this type if you want interactivity to take place.