Inside Macintosh: QuickTime /

Chapter 2 - Movie Toolbox / Movie Toolbox Reference

Functions That Modify Movie Properties / Working With Movie Spatial Characteristics

SetTrackMatte

The SetTrackMatte function allows your application to set a track's matte. The matte defines which of the track's pixels are displayed in a movie. You must specify the matte in a pixel map structure.

pascal void SetTrackMatte (Track theTrack, PixMapHandle theMatte);

theTrack

Specifies the track for this operation. Your application obtains this track identifier from such Movie Toolbox functions as NewMovieTrack and GetMovieTrack (described on page 2-136 and page 2-188, respectively).

theMatte

Contains a handle to the matte. The Movie Toolbox makes a copy of the matte, including its color table and pixels. Consequently, your application must dispose of the matte when you are done with it. Set this parameter to nil to remove the track's matte.

DESCRIPTION

The Movie Toolbox displays the weighted average of the track and its destination based on the corresponding pixel in the matte (this feature is fully functional in System 7 and is approximated in System 6).

SPECIAL CONSIDERATIONS

Note that the track matte must have its boundaries defined by the track rectangle.

ERROR CODES

invalidTrack

-2009

This track is corrupted or invalid

Memory Manager errors

SEE ALSO

You can retrieve a track's matte by calling the GetTrackMatte function, which is described in the next section. Listing 2-15 on page 2-62 shows how to use the SetTrackMatte and GetTrackMatte functions to create a track matte.