Legacy Document

Inside Macintosh: Imaging With QuickDraw /

Chapter 2 - Basic QuickDraw / Basic QuickDraw Reference

Routines / Managing Bitmaps, Port Rectangles, and Clipping Regions

BitMapToRegion

You can use the BitMapToRegion function to convert a bitmap or pixel map to a region.

FUNCTION BitMapToRegion (region: RgnHandle; bMap: BitMap): OSErr;

region

A handle to a region to hold the converted BitMap or PixMap record.

bMap

A BitMap or PixMap record.

DESCRIPTION

The BitMapToRegion function converts a given BitMap or PixMap record to a region. You would generally use this region later for drawing operations. The region parameter must be a valid region handle created with the NewRgn function (described in the chapter "QuickDraw Drawing"). The old region contents are lost.

The bMap parameter may be either a BitMap or PixMap record. If you pass a PixMap record, its pixel depth must be 1.

RESULT CODES

pixmapTooDeepErr	-148	Pixel map is deeper than 1 bit per pixel
rgnTooBigErr	-500	Bitmap would convert to a region greater than 64 KB