Microsoft Windows CE 3.0  


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This method, which is called prior to a sequence of clipped blit operations, identifies the appropriate functions needed to perform individual blits.

SCODE GPE::BltPrepare(


Pointer to a GPEBltParmsstructure containing parameters for the blit operation.

Return Values

S_OK indicates success.


The following code example shows the simplest acceptable implementation for GPE::BltPrepare.

pBltParms->pBlt = EmulatedBlt; return

This action causes the emulated blit function provided with GPE to be used for blit operations.

For improved performance, the BltPreparemethod can examine the characteristics of the blit and the associated surfaces defined in GPEBltParmsto determine whether an accelerated form of the blit is used. The following code example shows how to determine the operations that are likely to be implemented in hardware.

if( pBltParms->pDst->InVideoMemory()
&& pBltParms->rop4 == 0x0000 ) // This is a fill of
BLACKNESS in video memory. if(
pBltParms->pDst->InVideoMemory() &&
pBltParms->rop4 == 0xFFFF ) // This is a fill of WHITENESS in
video memory. if( pBltParms->pDst->InVideoMemory() &&
pBltParms->rop4 == 0xF0F0 && pBltParms->solidColor !=
0xFFFFFFFF ) // This is a fill of a solid color in video memory.
if( pBltParms->pDst->InVideoMemory() &&
pBltParms->pSrc->InVideoMemory() &&
pBltParms->rop4 == 0xCCCC && !pBltParms->pLookup
&& !pBltParms->pConvert ) // This is a source copy
(SRCCOPY) between two surfaces, both in // video memory, with no
color translation.

To accelerate these types of blit, BltPrepareplaces the address of the accelerated function in the pBltmember of the GPEBltParmsstructure, instead of the pointer to the EmulatedBltfunction. For operations such as solid color fills, the driver can prepare the hardware. For example, the driver can place a solid color into the appropriate register of the hardware. This eliminates the need to repeat the same action in every call to the accelerated blit handler.


Runs on Versions Defined in Include Link to
Windows CE OS 1.0 and later      
Note   This API is part of the complete Windows CE OS package as provided by Microsoft. The functionality of a particular platform is determined by the original equipment manufacturer (OEM) and some devices may not support this API.

 Last updated on Tuesday, July 13, 2004

© 2004 Microsoft Corporation. All rights reserved.