Calculates the intersection of two regions.

void SectRgn (
     srcRgnA, 
     srcRgnB, 
     dstRgn
);

Parameter descriptions

srcRgnA

A handle to the first of two regions whose intersection is to be determined.

srcRgnB

A handle to the second of two regions whose intersection is to be determined.

dstRgn

On return, a handle to the region holding the intersection area.If the regions do not intersect, or one of the regions is empty, SectRgn sets the destination to the empty region defined by the rectangle (0,0,0,0).

The SectRgn function does not create a destination region; you must have already allocated memory for it by using the NewRgn function.

The destination region may be one of the source regions, if desired.

DISCUSSION

The SectRgn procedure calculates the intersection of the two regions whose handles you pass in the srcRgnA and srcRgnB parameters, and it places the intersection in the region whose handle you pass in the dstRgn parameter. If the regions do not intersect, or one of the regions is empty, SectRgn sets the destination to the empty region defined by the rectangle (0,0,0,0).

The SectRgn procedure does not create a destination region; you must have already allocated memory for it by using the NewRgn function.

The destination region may be one of the source regions, if desired.

SPECIAL CONSIDERATIONS

The SectRgn function may temporarily use heap space that’s twice the size of the two input regions.

The SectRgn function may move or purge memory blocks in the application heap; do not call this function at interrupt time.

AVAILABILITY

Supported in Carbon. Available in Carbon 1.0.2 and later when running Mac OS 8.1 or later.

© 2000 Apple Computer, Inc. (Last Updated 6/30/2000)