Inside Macintosh: QuickTime Components /

Chapter 6 - Sequence Grabber Channel Components / Sequence Grabber Channel Components Reference

Functions / Configuration Functions for All Channel Components

SGSetChannelMatrix

The SGSetChannelMatrix function allows the sequence grabber to set your channel's display transformation matrix.

pascal ComponentResult SGSetChannelMatrix (SGChannel c, 
                                          const MatrixRecord *m);

c

Identifies the channel connection for this operation.

m

Contains a pointer to a matrix structure, as defined by the Movie Toolbox (see the chapter "Movie Toolbox" in Inside Macintosh: QuickTime for more information about matrix structures). This parameter is set to nil to select the identity matrix.

DESCRIPTION

The SGSetChannelMatrix function allows the sequence grabber to specify a display transformation matrix for a video channel. Your channel uses this matrix to transform its video image into the destination window. If your channel cannot accommodate the matrix, return an appropriate result code. Note that the sequence grabber may not call this function when you are recording.

Other channel component functions may affect this matrix. The SGSetChannelBounds function sets the matrix values so that the matrix maps the channel's output to the channel's boundary rectangle (described on page 6-60). The SGSetVideoRect function modifies the matrix so that the specified video rectangle appears in the existing destination rectangle (see page 6-62 for more information about the SGSetVideoRect function).

RESULT CODES

matrixErr	-2203	Invalid matrix
deviceCantMeetRequest	-9408	Device cannot support grabber

SEE ALSO

The sequence grabber may retrieve your channel's matrix by calling the SGGetChannelMatrix function, which is discussed next.

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