GPE::AllocSurface (Windows Embedded CE 6.0)
1/6/2010
This method executes when the driver must allocate storage for surface pixels.
Syntax
SCODE GPE::AllocSurface(
GPESurf** ppSurf,
int width,
int height,
EGPEFormat format,
int surfaceFlags
);
Parameters
- ppSurf
[out] Pointer to the memory allocated by the GPE::AllocSurface method.
- width
[in] Width, in pixels, of the surface to allocate.
- height
[in] Height, in pixels, of the surface to allocate.
- format
[in] Format of the surface.
- surfaceFlags
[in] One of the flags GPE_REQUIRE_VIDEO_MEMORY or GPE_PREFER_VIDEO_MEMORY, which specify where to allocate the memory
Return Value
If GPE_REQUIRE_VIDEO_MEMORY is set in the surfaceFlags parameter, the call returns one of two error values: if the available video memory is insufficient, the call returns E_NOT_ENOUGH_MEMORY, whereas if the allocation is inappropriate for video memory, such as an incorrect pixel format, the call returns E_INVALID_PARAMETER.
Remarks
Display drivers allocate surfaces at initialization time for the video frame buffer, and possibly the cursor, when the graphics device interface (GDI) calls the DrvCreateDeviceBitmap function. GPE::AllocSurface, a required method, implements surface allocation within the driver.
For video memory allocation, the driver should implement a class, derived from GPESurf that contains extra information, such as a pointer to the allocator used when freeing the memory. Refer to the Node2D class for information about a supplied memory allocator that you can use for rectangular allocation requirements.
The following code example shows the system memory allocation for this method.
*ppSurf = new GPESurf( width, height, format );
if(* ppSurf )
{
//check that the bitmap bits were allocated
if (NULL == ((*ppSurf)->Buffer()))
{
delete *ppSurf;
}
else
{
return S_OK;
}
}
return E_NOT_ENOUGH_MEMORY;
The surfaceFlags parameter can contain GPE_REQUIRE_VIDEO_MEMORY or GPE_PREFER_VIDEO_MEMORY, although neither is required. For GPE_PREFER_VIDEO_MEMORY, the driver should allocate, if possible, the surface from video memory. Otherwise, the driver should use system memory.
Requirements
| Header | gpe.h |
| Library | Gpe_lib.lib |
| Windows Embedded CE | Windows CE 1.0 and later |