Inside Macintosh: Imaging With QuickDraw /

Chapter 6 - Offscreen Graphics Worlds / Offscreen Graphics Worlds Reference

Routines / Managing an Offscreen Graphics World's Pixel Image

NoPurgePixels

To prevent the Memory Manager from purging the base address for an offscreen pixel image, use the NoPurgePixels procedure.

PROCEDURE NoPurgePixels (pm: PixMapHandle);

pm

A handle to an offscreen pixel map.

DESCRIPTION

The NoPurgePixels procedure marks the base address for an offscreen pixel image as unpurgeable. To get a handle to an offscreen pixel map, use the GetGWorldPixMap function, described on page 6-31. Then supply this handle for the pm parameter of NoPurgePixels.

SPECIAL CONSIDERATIONS

The NoPurgePixels procedure may move or purge memory blocks in the application heap. Your application should not call this procedure at interrupt time.

ASSEMBLY-LANGUAGE INFORMATION

The trap macro and routine selector for the NoPurgePixels procedure are

Trap macro	Selector
_QDExtensions	$0004000C

Main | Top of Section | What's New | Apple Computer, Inc. | Find It | Feedback | Help