Important: The information in this document is obsolete and should not be used for new development.
GetPixelsState
To save the current information about the memory allocated for an offscreen pixel image, you can use theGetPixelsState
function.
FUNCTION GetPixelsState (pm: PixMapHandle): GWorldFlags;
pm
- A handle to an offscreen pixel map.
DESCRIPTION
TheGetPixelsState
function returns information about the memory allocated for the base address for an offscreen pixel image. This information can be either of the following flags defined by theGWorldFlags
data type:
TYPE GWorldFlags = SET OF ( {flags for GetPixelsState only are listed here} pixelsPurgeable, {the base address for an offscreen pixel } { image is purgeable} pixelsLocked, {the offscreen pixel image is locked and } { not purgeable} );If thepixelsPurgeable
flag is not returned, then the base address for the offscreen pixel image is unpurgeable. If thepixelsLocked
flag is not returned, then the base address for the offscreen pixel image is unlocked.After using
GetPixelsState
to save this state information, your application can later use theSetPixelsState
procedure, described next, to restore this state to the offscreen graphics world.Specify a handle to a pixel map in the
pm
parameter. To get a handle to an offscreen pixel map, use theGetGWorldPixMap
function, described on page 6-31.SPECIAL CONSIDERATIONS
TheGetPixelsState
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 theGetPixelsState
function are
Trap macro Selector _QDExtensions $0004000D SEE ALSO
After usingGetPixelsState
and before usingSetPixelsState
, your application can temporarily use theAllowPurgePixels
procedure (described on page 6-34) to make the base address for an offscreen pixel image purgeable, theNoPurgePixels
procedure (described on page 6-35) to make it unpurgeable, theLockPixels
function (described on page 6-32) to prevent it from being moved, and theUnlockPixels
procedure (described on page 6-33) to allow it to be moved.