Legacy Document

Important: The information in this document is obsolete and should not be used for new development.

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