Inside Macintosh: QuickTime /

Chapter 2 - Movie Toolbox / Movie Toolbox Reference

Functions That Modify Movie Properties / Working With Movie Spatial Characteristics

GetTrackSegmentDisplayBoundsRgn

The GetTrackSegmentDisplayBoundsRgn function allows your application to determine the region a track occupies in a movie's graphics world during a specified segment.

pascal RgnHandle GetTrackSegmentDisplayBoundsRgn (Track theTrack, 
                                             TimeValue time,
                                             TimeValue duration);

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).

time

Specifies the starting time of the track segment to consider. This time value must be expressed in the movie's time coordinate system. The duration parameter specifies the length of the segment.

duration

Specifies the length of the segment to consider. Set this parameter to 0 to consider an instant in time.

DESCRIPTION

This region is in the display coordinate system. When combined with the movie's display clipping region, this region describes which pixels in the movie's graphics world display information from the specified track.

This region is valid for the specified segment.

The GetTrackSegmentDisplayBoundsRgn function allocates the region and returns a handle to the region. Your application must dispose of this region when you are done with it. If the track does not have a spatial representation during the specified segment, the function returns an empty region. If the function could not satisfy your request, it sets the returned handle to nil.

ERROR CODES

invalidTrack	-2009	This track is corrupted or invalid
invalidDuration	-2014	This duration value is invalid
invalidTime	-2015	This time value is invalid

Memory Manager errors

SEE ALSO

If you want to determine the track's boundary region for the current movie time, you can use the GetTrackDisplayBoundsRgn function, which is described in the previous section.