Legacy Document

Inside Macintosh: Imaging With QuickDraw /

Chapter 6 - Offscreen Graphics Worlds / Offscreen Graphics Worlds Reference

Routines / Saving and Restoring Graphics Ports and Offscreen Graphics Worlds

GetGWorldDevice

Use the GetGWorldDevice function to obtain a handle to the GDevice record associated with an offscreen graphics world.

FUNCTION GetGWorldDevice (offscreenGWorld: GWorldPtr): GDHandle;

offscreenGWorld

A pointer to an offscreen graphics world. The pointer returned to your application by the NewGWorld function.

DESCRIPTION

The GetGWorldDevice function returns a handle to the GDevice record associated with the offscreen graphics world specified by the offscreenGWorld parameter. In this parameter, supply the pointer returned to your application by the NewGWorld function when you created the offscreen graphics world. If you created the offscreen world by specifying the noNewDevice flag, the GDevice record is for one of the screen devices or is the GDevice record that you specified to NewGWorld or UpdateGWorld.

If you point to a GrafPort or CGrafPort record in the offscreenGWorld parameter, GetGWorldDevice returns the current device.

SPECIAL CONSIDERATIONS

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

ASSEMBLY-LANGUAGE INFORMATION

The trap macro and routine selector for the GetGWorldDevice function are

Trap macro	Selector
_QDExtensions	$00040012