Quicktime File Format (2012-08-14).pdf

Media Data Atom TypesSprite Button BehaviorsSprite Button BehaviorsNote Sprite media is deprecated in the QuickTime file format. The information that follows is intendedto document existing content containing sprite media and should not be used for new development.In QuickTime 4 and later, sprites in a sprite track can specify simple button behaviors. These behaviors cancontrol the sprite’s image, the system cursor, and the status message displayed in a Web browser. They alsoprovide a shortcut for a common set of actions that may result in more efficient QuickTime movies.Button behaviors can be added to a sprite. These behaviors are intended to make the common task of creatingbuttons in a sprite track easy—you basically just fill in a template.Three types of behaviors are available; you may choose one or more behaviors. Each change a type of propertyassociated with a button and are triggered by the mouse states notOverNotPressed, overNotPressed,overPressed, and notOverPressed. The three properties changed are:●●●The sprite’s imageIndexvalueThe ID of a cursor to be displayedThe ID of a status string variable displayed in the URL status area of a Web browser.Setting a property’s value to –1 means don’t change it.Note The cursor is automatically set back to the default system cursor when leaving a sprite.The sprite track handles letting one sprite act as an active button at a time.The behaviors are added at the beginning of the sprite’s list of actions, so they may be overridden by actionsif desired.To use the behaviors, you fill in the new atoms as follows, using the description key specified in “QT AtomContainer Description Key” (page 221):kSpriteAtomType, 1[QTSpriteButtonBehaviorStruct]2012-08-14 | © 2004, 2012 Apple Inc. All Rights Reserved.220