View source for GreSaveXform

GreSaveXform is called during SaveDC and OpenDC to allow simulations to save their local data structures. A Save with a count of one more than the current save level generates intervening levels. When a new DC is created, GreSaveXform is called with a count of 1 to initialize its local data.

This function can be hooked by the presentation driver.

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

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

==Parameters==
;hdc (HDC) - input:Device context handle.
;cSave (LONG) - input:DC save level. This must not be a negative value.
;pInstance (PVOID) - input:Pointer to instance data.
;lFunction (ULONG) - input:High-order WORD=flags; low-order WORD=NGreSaveXform.

==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_HDC_BUSY
:*PMERR_INSUFFICIENT_MEMORY
:*PMERR_INV_HDC.
:Refer to the "Error Explanations" section in the ''Presentation Manager Programming Reference'' for further explanation.

==Remarks==
When initializing a new DC, the default transform must be set.

==Sample Code==
<PRE>
#define INCL_GRE_XFORMS
#include <os2.h>

HDC      hdc;        /*  Device context handle. */
LONG     cSave;      /*  DC save level. This must not be a negative value. */
PVOID    pInstance;  /*  Pointer to instance data. */
ULONG    lFunction;  /*  High-order WORD=flags; low-order WORD=NGreSaveXform. */
BOOL     fSuccess;   /*  Return codes. */

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

[[Category:Gre]]