Programming With QuickTime VR

Movie Controller Actions

A movie controller action is a constant that you can pass to a movie controller to request that the movie controller perform some action (such as modify certain movie characteristics or respond to user events). For example, you can pass the mcActionSetCursorSettingEnabled action to enable or disable the automatic cursor tracking and shape changing provided by the QuickTime VR movie controller.

There are two ways in which you might be concerned with these actions: your application can invoke these actions directly by calling the MCDoAction function; or your application can install an action filter function, which can receive any of these actions; your action filter can then either intercept the action or send it back to the movie controller for processing.

A movie controller action is usually accompanied by some parameter data. For instance, the mcActionSetCursorSettingEnabled action must be accompanied by a Boolean value that indicates whether to enable or disable cursor tracking and shape changing. When calling MCDoAction , you get or set data through the params parameter. Similarly, an action filter function exchanges data with a movie controller through its params parameter. The type and meaning of this additional parameter data are described in the individual descriptions of each movie controller action. See "Movie Controller Actions" .

For complete information on handling movie controller actions, see the chapter "Movie Controller Components" in the book Inside Macintosh: QuickTime Components .