Determines whether a region is empty.

Boolean EmptyRgn (
     rgn
);

rgn

A handle to the region to test for emptiness.

function result

TRUE if the region whose handle you pass in the rgn parameter is an empty region or FALSE if it is not.

DISCUSSION

The EmptyRgn function does not create an empty region. To create an empty region, you can perform any of the following operations:

• Use NewRgn.
• Pass the handle to an empty region to CopyRgn.
• Pass an empty rectangle to either SetRectRgn or RectRgn.
• Call CloseRgn without a previous call to OpenRgn.
• Call CloseRgn without performing any drawing after calling OpenRgn.
• Pass an empty region to OffsetRgn.
• Pass an empty region or too large an inset to InsetRgn
• Pass two nonintersecting regions to SectRgn.
• Pass two empty regions to UnionRgn.
• Pass two identical or nonintersecting regions to DiffRgn or XorRgn.

AVAILABILITY

Supported in Carbon. Available in CarbonLib 1.0 and later when InterfaceLib 7.1 or later is installed. Exported by CarbonLib 1.0 and later and by InterfaceLib 7.1 and later.

© 2000 Apple Computer, Inc. — (Last Updated 4/14/2000)