QTMTB 26 - Choosing the Position Where a Movie is Pasted
Technical Q&A's
QTMTB 26 - Choosing the Position Where a Movie is Pasted (1-May-95)
Q When a user pastes a movie into a movie controller movie, the added movie is
inserted in the top left corner of the movie. Is there a way for the user to
choose the position where the movie is pasted? If not, how can I give the movie
controller or Movie Toolbox an offset to use rather than have the editing
operations use the top left corner?
A When you paste a movie into a movie-controller movie, the movie controller
calls PasteMovieSelection to insert the source movie. Since all the
characteristics of the movie are inserted, the pasted movie is inserted in the
top left corner of the movie-controller movie. There's no easy way to specify
an offset directly to the movie controller. If you need to change the offset of
the pasted movie, you have to modify the movie yourself after the paste using
Movie Toolbox commands. Once you're done changing the movie, be sure to call
MCMovieChanged so that the movie controller updates correctly.
The actual modification is simple: call GetTrackMatrix, add your offset to the
matrix, and call SetTrackMatrix. The only difficulty is in determining which
tracks to modify, since the paste may either create a new track or use an
existing one. We recommend doing this by gathering all track IDs before the
paste, and then comparing them with the track IDs after the paste. Since most
movies these days have just a few tracks, this shouldn't require much overhead,
but be warned -- some movies do have a lot of tracks! To get the track
information, call GetMovieTrackCount and GetMovieIndTrack.
Here's one last idea: If you don't mind changing the source movie, offset the
source movie before the paste as an alternative method.
