Undo for Movies
The Movie Toolbox provides functions that allow you to capture and restore the edit state of a movie. An edit state contains information that completely defines a movie's content at the time you create the edit state. It is, in essence, a checkpoint in the edit session. You can manage a movie's edit states in order to implement an undo capability for editing movies. For example, you can capture a movie's edit state before performing an editing operation, such as a cut, and later restore the old state. You can have several movie edit states obtained at different times during an editing session, and restore to any one of them at any time. In this manner, you can provide a multilevel undo capability. This section describes the Movie Toolbox functions that work with edit states.Note that a movie's edit state does not save everything about a movie. Most important, the edit state does not contain information about the movie's spatial characteristics. For example, the edit state does not store the current boundary rectangle or clipping region. Consequently, edit states are best suited to supporting undo operations involving movie content, including track creation and removal. You can use other Movie Toolbox functions to support undo operations for movie characteristics. See "Functions That Modify Movie Properties" beginning on page 2-142 to learn more about these functions.
You can use the
NewMovieEditStatefunction to capture a movie's edit state. Use theUseMovieEditStateto restore the movie to its condition according to a previous edit state. Your application must dispose of an edit state by calling theDisposeMovieEditStatefunction. You must dispose of a movie's edit states before you dispose of the movie.
Subtopics
- NewMovieEditState
- UseMovieEditState
- DisposeMovieEditState