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Chapter 5 - Sequence Grabber Components / Sequence Grabber Components Reference

Sequence Grabber Component Functions / Utility Functions for Video Channel Callback Functions

SGDisplayFrame

The SGDisplayFrame function provides the default behavior for your display function.

pascal ComponentResult SGDisplayFrame (SGChannel c, 
                                       short bufferNum,
                                       MatrixRecord *mp, 
                                       RgnHandle clipRgn);

c

Specifies the reference that identifies the channel for this operation. The sequence grabber component provides this value to your display function.

bufferNum

Identifies the buffer. The sequence grabber component provides this value to your display function.

mp

Contains a pointer to a transformation matrix for the display operation. If there is no matrix for the operation, set this parameter to nil.

clipRgn

Contains a handle to the clipping region for the destination image. This region is defined in the destination coordinate system. If there is no clipping region, set this parameter to nil.

SPECIAL CONSIDERATIONS

You should call the SGDisplayFramefunction only from your display function.
If you call it at any other time, results are unpredictable.

RESULT CODE

cantDoThatInCurrentMode

-9402

Request invalid in current mode

SEE ALSO

See "Application-Defined Functions," which begins on page 5-107, for details about display functions.

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