View source for GreRestoreRegion

GreRestoreRegion is called during RestoreDC and CloseDC to allow the region handling routines to restore their local data structures. When a DC is closed, GreRestoreRegion is called with a count of 0 to free its local data. The clip region currently selected into the DC is deleted by this function.

This function can be hooked by the presentation driver.

;Simulation support: This function is simulated by a handling routine in the graphics engine.

==Syntax==
 GreRestoreRegion(hdc, cSave, pInstance, lFunction)

==Parameters==
;hdc (HDC) - input:Device context handle.
;cSave (LONG) - input:DC save level.
:Indicates the saved DC state, which the handling routine uses to restore the region. When this is passed as -1, the handling routine resets the region to its initial state (-1 is passed to this routine from [[GreResetDC]] and is the only valid negative value). A value of 0 indicates that the region is restored to its initial state. Other positive values identify which saved level is restored. See RestoreDCState.
;pInstance (PVOID) - input:Pointer to instance data.
;lFunction (ULONG) - input:High-order WORD=flags; low-order WORD=NGreRestoreRegion.

==Return Code==
;fSuccess (BOOL) - returns:Return codes.
:This function returns BOOLEAN (fSuccess).
:*TRUE Successful
:*FALSE Error
:Possible Errors Detected: When an error is detected, the handling routine must call WinSetErrorInfo to post the condition. Error codes for conditions that the handling routine is expected to check include:
:*PMERR_DEV_FUNC_NOT_INSTALLED
:*PMERR_HDC_BUSY
:*PMERR_INSUFFICIENT_MEMORY
:*PMERR_INV_COORDINATE
:*PMERR_INV_HDC
:*PMERR_INV_HRGN
:*PMERR_INV_RECT
:*PMERR_INV_REGION_CONTROL
:Refer to the "Error Explanations" section in the ''Presentation Manager Programming Reference'' for further explanation.

==Remarks==
This function is required to ensure that memory is freed.

==Declaration==
<PRE>
#define INCL_GRE_CLIP
#include <os2.h>

HDC      hdc;        /*  Device context handle. */
LONG     cSave;      /*  DC save level. */
PVOID    pInstance;  /*  Pointer to instance data. */
ULONG    lFunction;  /*  High-order WORD=flags; low-order WORD=NGreRestoreRegion. */
BOOL     fSuccess;   /*  Return codes. */

fSuccess = GreRestoreRegion(hdc, cSave, pInstance, lFunction);
</PRE>

[[Category:Gre]]